@article {164006, title = {The lipid language of tuberculosis: surface molecules in host interaction and drug resistance.}, journal = {mBio}, year = {2026}, month = {2026 Feb 02}, pages = {e0395925}, abstract = {

(), the causative agent of tuberculosis (TB), is a uniquely successful pathogen due in large part to its complex lipid-rich cell envelope. Comprising nearly 40\% of its dry weight, lipids-such as mycolic acids, phthiocerol dimycocerosates (PDIM), trehalose dimycolate (TDM), and sulfolipids (SLs)-play crucial roles in infection, immune evasion, intracellular persistence, granuloma formation, transmission, and drug resistance. These lipids modulate host-pathogen interactions by altering host membrane biophysics, hijacking phagosome maturation, and interfering with host immune pathways, including autophagy and inflammatory signaling. Upon inhalation, surface lipids inhibit pulmonary surfactant function and mask pathogen-associated molecular patterns, facilitating uptake by permissive macrophage subsets. Intracellularly, lipoglycans like mannose-capped lipoarabinomannan block phagolysosome fusion, while PDIM and TDM promote phagosomal escape and subversion of vesicular trafficking. Lipid-mediated modulation of autophagy pathways further enhances bacterial survival within host cells. In addition to shaping host immune responses, lipids orchestrate granuloma development and promote pathological features such as foam cell formation and caseation, which are central to transmission. Specifically, phenolic glycolipids and SLs stimulate neuronal pathways, triggering cough, thereby facilitating aerosol spread. Finally, the lipid-rich envelope acts as a formidable barrier to antibiotics, with resistance partly driven by the altered lipid composition and architecture in multidrug-resistant strains. Targeting lipid biosynthesis and transport pathways offers promising avenues for novel anti-TB therapies. This review highlights the multifaceted roles of lipids at the host-pathogen interface, recent technical advances enabling these insights, and emerging challenges in translating lipid biology into improved TB control.

}, keywords = {cell wall, Host-Pathogen Interactions, Mtb lipids, multidrug resistance, Mycobacterium tuberculosis, pathogenesis.}, issn = {2150-7511}, doi = {10.1128/mbio.03959-25}, url = {https://pubmed.ncbi.nlm.nih.gov/41627032/}, author = {Radhakrishnan, Sandhya Krishnan and Sundaramurthy, Varadharajan} } @article {158955, title = {Combating Tuberculosis: Obstacles, Innovations, and the Road Ahead.}, journal = {ACS Infect Dis}, volume = {11}, year = {2025}, month = {2025 Jul 11}, pages = {1754-1755}, issn = {2373-8227}, doi = {10.1021/acsinfecdis.5c00495}, author = {Sundaramurthy, Varadharajan and Strauss, Erick} } @article {161139, title = {Fundamental role of spatial positioning of Mycobacterium tuberculosis in mycobacterial survival in macrophages.}, journal = {Nature Communications}, year = {2025}, type = {Journal}, doi = {https://doi.org/10.1038/s41467-025-64404-z}, author = {Sahu, S{\textquoteright} and Baid, N{\textquoteright} and Aggarwal, D{\textquoteright} and Sharma, A{\textquoteright} and Gun, M{\textquoteright} and Molla, S{\textquoteright} and Sinha, A{\textquoteright} and Dwivedi, A.P{\textquoteright} and Tuli, A{\textquoteright} and Sharma, M{\textquoteright} and Khosla, S{\textquoteright} and Sundaramurthy, Varadharajan and Kumar, A{\textquoteright}} } @article {157492, title = {M. tuberculosis surface sulfoglycolipid SL-1 activates the mechanosensitive channel TRPV4 to enhance lysosomal biogenesis and exocytosis in macrophages}, journal = {Mol Biol Cell}, volume = {36}, year = {2025}, month = {2025 Jun 01}, pages = {ar76}, abstract = {

Intracellular pathogens manipulate host cellular pathways to ensure their survival. (Mtb) disrupts phagosomal trafficking to prevent fusion with lysosomes. Beyond this localized effect, Mtb globally remodels the host lysosomal system, predominantly through its virulence-associated surface lipid, sulfolipid-1 (SL-1). SL-1 enhances lysosomal biogenesis via the mTORC1-TFEB axis; however, the upstream mediators remain unknown. Here, we show that SL-1 induces calcium influx into macrophages and identify the mechanosensitive calcium channel transient receptor potential vanilloid subtype 4 (TRPV4) as a crucial upstream mediator of SL-1-induced lysosomal remodeling. TRPV4 influences multiple aspects of lysosomal function, including biogenesis, acidification, enzymatic activity, phagosome maturation, and lysosomal exocytosis. These effects are recapitulated during Mtb infection, underscoring the relevance of SL-1- and TRPV4-dependent lysosomal remodeling in an infection context. TRPV4 expression is upregulated during Mtb infection and partially localizes to both lysosomes and the Mtb-containing vacuole. Remarkably, TRPV4 activation, independent of SL-1, is sufficient to enhance lysosomal biogenesis, identifying TRPV4 as a key regulator of lysosomal homeostasis. Together, these findings uncover a novel mechanism of lysosomal remodeling driven by a pathogen lipid virulence factor and reveal a previously unrecognized role for TRPV4 in modulating lysosomal homeostasis in macrophages.

}, keywords = {Animals, Basic Helix-Loop-Helix Leucine Zipper Transcription Factors, Calcium, Exocytosis, Glycolipids, Humans, Lysosomes, Macrophages, Mice, Mice, Inbred C57BL, Mycobacterium tuberculosis, Phagosomes, TRPV Cation Channels}, issn = {1939-4586}, doi = {10.1091/mbc.E24-12-0560}, url = {https://www.molbiolcell.org/doi/10.1091/mbc.E24-12-0560?url_ver=Z39.88-2003\&rfr_id=ori:rid:crossref.org\&rfr_dat=cr_pub\%20\%200pubmed}, author = {Umar, Ibrahim and Gulzar, Shah-E-Jahan and Sundaramurthy, Varadharajan} } @article {149406, title = {Honoring a Legacy: "Vigyan Ratna" Prof. G. Padmanaban.}, journal = {ACS Infect Dis}, year = {2024}, month = {2024 Oct 03}, issn = {2373-8227}, doi = {10.1021/acsinfecdis.4c00759}, author = {Sundaramurthy, Varadharajan and Haldar, Jayanta} } @article {140659, title = {Immunogenicity of SARS-CoV-2 vaccines BBV152 (COVAXIN{\textregistered}) and ChAdOx1 nCoV-19 (COVISHIELD{\texttrademark}) in seronegative and seropositive individuals in India: a multicentre, nonrandomised observational study.}, journal = {Lancet Reg Health Southeast Asia}, volume = {22}, year = {2024}, month = {2024 Mar}, pages = {100361}, abstract = {

BACKGROUND: There are limited global data on head-to-head comparisons of vaccine platforms assessing both humoral and cellular immune responses, stratified by pre-vaccination serostatus. The COVID-19 vaccination drive for the Indian population in the age group 18-45 years began in April 2021 when seropositivity rates in the general population were rising due to the delta wave of COVID-19 pandemic during April-May\ 2021.

METHODS: Between June 30, 2021, and Jan 28, 2022, we enrolled 691 participants in the age group 18-45 years across four clinical sites in India. In this non-randomised and laboratory blinded study, participants received either two doses of Covaxin{\textregistered} (4 weeks apart) or two doses of Covishield{\texttrademark} (12 weeks apart) as per the national vaccination policy. The primary outcome was the seroconversion rate and the geometric mean titre (GMT) of antibodies against the SARS-CoV-2 spike and nucleocapsid proteins post two doses. The secondary outcome was the frequency of cellular immune responses pre- and post-vaccination.

FINDINGS: When compared to pre-vaccination baseline, both vaccines elicited statistically significant seroconversion and binding antibody levels in both seronegative and seropositive individuals. In the per-protocol cohort, Covishield{\texttrademark} elicited higher antibody responses than Covaxin{\textregistered} as measured by seroconversion rate (98.3\% vs 74.4\%, p\ \<\ 0.0001 in seronegative individuals; 91.7\% vs 66.9\%, p\ \<\ 0.0001 in seropositive individuals) as well as by anti-spike antibody levels against the ancestral strain (GMT 1272.1 vs 75.4 binding antibody units/ml [BAU/ml], p\ \<\ 0.0001 in seronegative individuals; 2089.07 vs 585.7 BAU/ml, p\ \<\ 0.0001 in seropositive individuals). As participants at all clinical sites were not recruited at the same time, site-specific immunogenicity was impacted by the timing of vaccination relative to the delta and omicron waves. Surrogate neutralising antibody responses against variants-of-concern including delta and omicron was higher in Covishield{\texttrademark} recipients than in Covaxin{\textregistered} recipients; and in seropositive than in seronegative individuals after both vaccination and asymptomatic infection (omicron variant). T cell responses are reported from only one of the four site cohorts where the vaccination schedule preceded the omicron wave. In seronegative individuals, Covishield{\texttrademark} elicited both CD4+ and CD8+ spike-specific cytokine-producing T cells whereas Covaxin{\textregistered} elicited mainly CD4+ spike-specific T cells. Neither vaccine showed significant post-vaccination expansion of spike-specific T cells in seropositive individuals.

INTERPRETATION: Covishield{\texttrademark} elicited immune responses of higher magnitude and breadth than Covaxin{\textregistered} in both seronegative individuals and seropositive individuals, across cohorts representing the pre-vaccination immune history of most of the vaccinated Indian population.

FUNDING: Corporate social responsibility (CSR) funding from Hindustan Unilever Limited (HUL) and Unilever India Pvt. Ltd. (UIPL).

}, issn = {2772-3682}, doi = {10.1016/j.lansea.2024.100361}, author = {Asokan, Mangaiarkarasi S and Joan, Roshni Florina and Babji, Sudhir and Dayma, Girish and Nadukkandy, Prajitha and Subrahmanyam, Vinutha and Pandey, Archana and Malagi, Girish and Arya, Pooja and Mahajan, Vibhuti and Bhavikatti, Jayateerth and Pawar, Ketakee and Thorat, Aishwarya and Shah, Priyanki and Goud, Ramakrishna B and Roy, Bishnudeo and Rajukutty, Shon and Immanuel, Sushil and Agarwal, Dhiraj and Saha, Sankhanil and Shivaraj, Akshatha and Panikulam, Patricia and Shome, Rajeshwari and Gulzar, Shah-E-Jahan and Sharma, Anusmrithi U and Naik, Ajinkya and Talashi, Shruti and Belekar, Madhuri and Yadav, Ritu and Khude, Poornima and V, Mamatha and Shivalingaiah, Sudarshan and Deshmukh, Urmila and Bhise, Chinmayee and Joshi, Manjiri and Inbaraj, Leeberk Raja and Chandrasingh, Sindhulina and Ghose, Aurnab and Jamora, Colin and Karumbati, Anandi S and Sundaramurthy, Varadharajan and Johnson, Avita and Ramesh, Naveen and Chetan, Nirutha and Parthiban, Chaitra and Ahmed, Asma and Rakshit, Srabanti and Adiga, Vasista and D{\textquoteright}Souza, George and Rale, Vinay and George, Carolin Elizabeth and John, Jacob and Kawade, Anand and Chaturvedi, Akanksha and Raghunathan, Anu and Dias, Mary and Bhosale, Anand and Raghu, Padinjat and Shashidhara, L S and Vyakarnam, Annapurna and Bal, Vineeta and Kang, Gagandeep and Mayor, Satyajit} } @article {137335, title = {Niacinamide enhances cathelicidin mediated SARS-CoV-2 membrane disruption.}, journal = {Front Immunol}, volume = {14}, year = {2023}, month = {2023}, pages = {1255478}, abstract = {

The continual emergence of SARS-CoV-2 variants threatens to compromise the effectiveness of worldwide vaccination programs, and highlights the need for complementary strategies for a sustainable containment plan. An effective approach is to mobilize the body{\textquoteright}s own antimicrobial peptides (AMPs), to combat SARS-CoV-2 infection and propagation. We have found that human cathelicidin (LL37), an AMP found at epithelial barriers as well as in various bodily fluids, has the capacity to neutralise multiple strains of SARS-CoV-2. Biophysical and computational studies indicate that LL37{\textquoteright}s mechanism of action is through the disruption of the viral membrane. This antiviral activity of LL37 is enhanced by the hydrotropic action of niacinamide, which may increase the bioavailability of the AMP. Interestingly, we observed an inverse correlation between LL37 levels and disease severity of COVID-19 positive patients, suggesting enhancement of AMP response as a potential therapeutic avenue to mitigate disease severity. The combination of niacinamide and LL37 is a potent antiviral formulation that targets viral membranes of various variants and can be an effective strategy to overcome vaccine escape.

}, keywords = {Antimicrobial Cationic Peptides, Antiviral Agents, Cathelicidins, COVID-19, Humans, Niacinamide, SARS-CoV-2}, issn = {1664-3224}, doi = {10.3389/fimmu.2023.1255478}, author = {Bhatt, Tanay and Dam, Binita and Khedkar, Sneha Uday and Lall, Sahil and Pandey, Subhashini and Kataria, Sunny and Ajnabi, Johan and Gulzar, Shah-E-Jahan and Dias, Paul M and Waskar, Morris and Raut, Janhavi and Sundaramurthy, Varadharajan and Vemula, Praveen Kumar and Ghatlia, Naresh and Majumdar, Amitabha and Jamora, Colin} } @article {111547, title = {Active APPL1 sequestration by Plasmodium favors liver-stage development.}, journal = {Cell Rep}, volume = {39}, year = {2022}, month = {2022 May 31}, pages = {110886}, abstract = {

Intracellular pathogens manipulate host cells to survive and thrive. Cellular sensing and signaling pathways are among the key host machineries deregulated to favor infection. In this study, we show that liver-stage Plasmodium parasites compete with the host to sequester a host endosomal-adaptor protein (APPL1) known to regulate signaling in response to endocytosis. The enrichment of APPL1 at the parasitophorous vacuole membrane (PVM) involves an atypical Plasmodium Rab5 isoform (Rab5b). Depletion of host APPL1 alters neither the infection nor parasite development; however, upon overexpression of a GTPase-deficient host Rab5 mutant (hRab5_Q79L), the parasites are smaller and their PVM is stripped of APPL1. Infection with the GTPase-deficient Plasmodium berghei Rab5b mutant (PbRab5b_Q91L) in this case rescues the PVM APPL1 signal and parasite size. In summary, we observe a robust correlation between the level of APPL1 retention at the PVM and parasite size during exoerythrocytic development.

}, issn = {2211-1247}, doi = {10.1016/j.celrep.2022.110886}, author = {Lahree, Aparajita and Baptista, Sara de Jesus Santos and Marques, Sofia and Perschin, Veronika and Zuzarte-Lu{\'\i}s, Vanessa and Goel, Manisha and Choudhary, Hadi Hasan and Mishra, Satish and Stigloher, Christian and Zerial, Marino and Sundaramurthy, Varadharajan and Mota, Maria M} } @article {93663, title = {Advances in host-based screening for compounds with intracellular anti-mycobacterial activity.}, journal = {Cell Microbiol}, year = {2021}, month = {2021 Apr 04}, pages = {e13337}, abstract = {

Intracellular pathogens interact with host systems in intimate ways to sustain a pathogenic lifestyle. Consequently, these interactions can potentially be targets of host-directed interventions against infectious diseases. In case of tuberculosis (TB), caused by the bacterium Mycobacterium tuberculosis (Mtb), while effective anti-tubercular compounds are available, the long treatment duration and emerging drug resistance necessitate identification of new class of molecules with anti-TB activity, as well as new treatment strategies. A significant part of the effort in finding new anti-TB drugs is focused on bacterial targets in bacterial systems. However, the host environment plays a major role in pathogenesis mechanisms and must be considered actively in these efforts. On the one hand, the bacterial origin targets must be relevant and accessible in the host, while on the other hand, new host origin targets required for the bacterial survival can be targeted. Such targets are good candidates for host-directed therapeutics, a strategy gaining traction as an adjunct in TB treatment. In this review, we will summarise the screening platforms used to identify compounds with anti-tubercular activities inside different host environments and outline recent technical advances in these platforms. Finally, while the examples given are specific to mycobacteria, the methods and principles outlined are broadly applicable to most intracellular infections.

}, issn = {1462-5822}, doi = {10.1111/cmi.13337}, author = {Subhash, Neeraja and Sundaramurthy, Varadharajan} } @article {95906, title = {Strategies to target SARS-CoV-2 entry and infection using dual mechanisms of inhibition by acidification inhibitors.}, journal = {PLoS Pathog}, volume = {17}, year = {2021}, month = {2021 Jul 12}, pages = {e1009706}, abstract = {

Many viruses utilize the host endo-lysosomal network for infection. Tracing the endocytic itinerary of SARS-CoV-2 can provide insights into viral trafficking and aid in designing new therapeutic strategies. Here, we demonstrate that the receptor binding domain (RBD) of SARS-CoV-2 spike protein is internalized via the pH-dependent CLIC/GEEC (CG) endocytic pathway in human gastric-adenocarcinoma (AGS) cells expressing undetectable levels of ACE2. Ectopic expression of ACE2 (AGS-ACE2) results in RBD traffic via both CG and clathrin-mediated endocytosis. Endosomal acidification inhibitors like BafilomycinA1 and NH4Cl, which inhibit the CG pathway, reduce the uptake of RBD and impede Spike-pseudoviral infection in both AGS and AGS-ACE2 cells. The inhibition by BafilomycinA1 was found to be distinct from Chloroquine which neither affects RBD uptake nor alters endosomal pH, yet attenuates Spike-pseudovirus entry. By screening a subset of FDA-approved inhibitors for functionality similar to BafilomycinA1, we identified Niclosamide as a SARS-CoV-2 entry inhibitor. Further validation using a clinical isolate of SARS-CoV-2 in AGS-ACE2 and Vero cells confirmed its antiviral effect. We propose that Niclosamide, and other drugs which neutralize endosomal pH as well as inhibit the endocytic uptake, could provide broader applicability in subverting infection of viruses entering host cells via a pH-dependent endocytic pathway.

}, issn = {1553-7374}, doi = {10.1371/journal.ppat.1009706}, author = {Prabhakara, Chaitra and Godbole, Rashmi and Sil, Parijat and Jahnavi, Sowmya and Gulzar, Shah-E-Jahan and van Zanten, Thomas S and Sheth, Dhruv and Subhash, Neeraja and Chandra, Anchal and Shivaraj, Akshatha and Panikulam, Patricia and U, Ibrahim and Nuthakki, Vijay Kumar and Puthiyapurayil, Theja Parassini and Ahmed, Riyaz and Najar, Ashaq Hussain and Lingamallu, Sai Manoz and Das, Snigdhadev and Mahajan, Bhagyashri and Vemula, Praveen and Bharate, Sandip B and Singh, Parvinder Pal and Vishwakarma, Ram and Guha, Arjun and Sundaramurthy, Varadharajan and Mayor, Satyajit} } @article {73034, title = {Association of With the Apical Domain of Hepatocytes Is Necessary for the Parasite{\textquoteright}s Liver Stage Development.}, journal = {Front Cell Infect Microbiol}, volume = {9}, year = {2020}, month = {2019}, pages = {451}, abstract = {

parasites undergo a dramatic transformation during the liver stage of their life cycle, amplifying over 10,000-fold inside infected hepatocytes within a few days. Such a rapid growth requires large-scale interactions with, and manipulations of, host cell functions. Whereas hepatocyte polarity is well-known to be critical for liver function, little is presently known about its involvement during the liver stage of development. Apical domains of hepatocytes are critical components of their polarity machinery and constitute the bile canalicular network, which is central to liver function. Here, we employed high resolution 3-D imaging and advanced image analysis of -infected liver tissues to show that the parasite associates preferentially with the apical domain of hepatocytes and induces alterations in the organization of these regions, resulting in localized changes in the bile canalicular architecture in the liver tissue. Pharmacological perturbation of the bile canalicular network by modulation of AMPK activity reduces the parasite{\textquoteright}s association with bile canaliculi and arrests the parasite development. Our findings using -infected liver tissues reveal a host- interaction at the level of liver tissue organization. We demonstrate for the first time a role for bile canaliculi, a central component of the hepatocyte polarity machinery, during the liver stage of development.

}, issn = {2235-2988}, doi = {10.3389/fcimb.2019.00451}, author = {Balasubramanian, Lakshmi and Zuzarte-Lu{\'\i}s, Vanessa and Syed, Tabish and Mullick, Debakshi and Deb, Saptarathi and Ranga-Prasad, Harish and Meissner, Jana and Almeida, Ana and Furstenhaupt, Tobias and Siddiqi, Kaleem and Prud{\^e}ncio, Miguel and Rodrigues, Cecilia M P and Mota, Maria and Sundaramurthy, Varadharajan} } @article {85902, title = {Disrupting Plasmodium UIS3-host LC3 interaction with a small molecule causes parasite elimination from host cells.}, journal = {Commun Biol}, volume = {3}, year = {2020}, month = {2020 Nov 19}, pages = {688}, abstract = {

The malaria parasite Plasmodium obligatorily infects and replicates inside hepatocytes surrounded by a parasitophorous vacuole membrane (PVM), which is decorated by the host-cell derived autophagy protein LC3. We have previously shown that the parasite-derived, PVM-resident protein UIS3 sequesters LC3 to avoid parasite elimination by autophagy from hepatocytes. Here we show that a small molecule capable of disrupting this interaction triggers parasite elimination in a host cell autophagy-dependent manner. Molecular docking analysis of more than 20 million compounds combined with a phenotypic screen identified one molecule, C4 (4-{[4-(4-{5-[3-(trifluoromethyl) phenyl]-1,2,4-oxadiazol-3-yl}benzyl)piperazino]carbonyl}benzonitrile), capable of impairing infection. Using biophysical assays, we established that this impairment is due to the ability of C4 to disrupt UIS3-LC3 interaction, thus inhibiting the parasite{\textquoteright}s ability to evade the host autophagy response. C4 impacts infection in autophagy-sufficient cells without harming the normal autophagy pathway of the host cell. This study, by revealing the disruption of a critical host-parasite interaction without affecting the host{\textquoteright}s normal function, uncovers an efficient anti-malarial strategy to prevent this deadly disease.

}, issn = {2399-3642}, doi = {10.1038/s42003-020-01422-1}, author = {Setua, Sonali and Enguita, Francisco J and Chora, {\^A}ngelo Ferreira and Ranga-Prasad, Harish and Lahree, Aparajita and Marques, Sofia and Sundaramurthy, Varadharajan and Mota, Maria M} } @article {79735, title = {Heterogeneity in the endocytic capacity of individual macrophage in a population determines its subsequent phagocytosis, infectivity and subcellular trafficking.}, journal = {Traffic}, volume = {21}, year = {2020}, month = {2020 Aug}, pages = {522-533}, abstract = {

Phagocytosis is a complex cellular uptake process involving multiple distinct steps of cargo recognition, uptake, phagosome maturation and eventual phagolysosome resolution. Emerging literature shows that heterogeneity of phagocytosis at multiple steps at a single cell level influences the population outcome. However, the determinants of phagocytic heterogeneity are not clear. Here we show that the variance in the endocytic capacity of individual cells in a macrophage population determines subsequent phagocytic uptake and trafficking. Our results document the extensive heterogeneity in the endocytic uptake of individual macrophages, and show that cells with higher endocytic capacity preferentially phagocytose diverse cargo, including pathogenic Mycobacterium tuberculosis. Interestingly, M. tuberculosis infected cells sustain the higher endocytic capacity following infection. Modulating endocytic capacity by inhibiting endocytosis reduces phagocytic uptake. Differential uptake of M. tuberculosis into cells with different endocytic capacities correlates with the efficiency of phagocytic delivery to lysosomes, thus contributing further to phagocytic as well as mycobacterial heterogeneity. Thus, variance in endocytic capacity is a determinant of generating heterogeneity in phagocytosis at multiple steps.

}, issn = {1600-0854}, doi = {10.1111/tra.12752}, author = {Sachdeva, Kuldeep and Goel, Manisha and Sundaramurthy, Varadharajan} } @article {85901, title = {Measurement of Alcohol-Dependent Physiological Changes in Red Blood Cells Using Resistive Pulse Sensing.}, journal = {ACS Sens}, year = {2020}, month = {2020 Nov 18}, abstract = {

Alcohol exposure has been postulated to adversely affect the physiology and function of the red blood cells (RBCs). The global pervasiveness of alcohol abuse, causing health issues and social problems, makes it imperative to resolve the physiological effects of alcohol on RBC physiology. Alcohol consumed recreationally or otherwise almost immediately alters cell physiology in ways that is subtle and still unresolved. In this paper, we introduce a high-resolution device for quantitative electrofluidic measurement of changes in RBC volume upon alcohol exposure. We present an exhaustive calibration of our device using model cells to measure and resolve volume changes down to 0.6 fL. We find an RBC shrinkage of 5.3\% at 0.125\% ethanol (the legal limit in the United States) and a shrinkage of 18.5\% at 0.5\% ethanol (the lethal limit) exposure. Further, we also measure the time dependence of cell volume shrinkage (upon alcohol exposure) and then recovery (upon alcohol removal) to quantify shrinkage and recovery of RBC volumes. This work presents the first direct quantification of temporal and concentration-dependent changes in red blood cell volume upon ethanol exposure. Our device presents a universally applicable high-resolution and high-throughput platform to measure changes in cell physiology under native and diseased conditions.

}, issn = {2379-3694}, doi = {10.1021/acssensors.0c01302}, author = {Kaushik, Saurabh and Mahadeva, Manohara and Sundaramurthy, Varadharajan and Soni, Gautam Vivek} } @article {79734, title = {Mycobacterium tuberculosis ( Mtb) lipid mediated lysosomal rewiring in infected macrophages modulates intracellular Mtb trafficking and survival}, journal = {J Biol Chem}, volume = {295}, year = {2020}, month = {2020 Jul 03}, pages = {9192-9210}, abstract = {

Intracellular pathogens commonly manipulate the host lysosomal system for their survival. However, whether this pathogen-induced alteration affects the organization and functioning of the lysosomal system itself is not known. Here, using and infections and quantitative image analysis, we show that the lysosomal content and activity are globally elevated in ()-infected macrophages. We observed that this enhanced lysosomal state is sustained over time and defines an adaptive homeostasis in the infected macrophage. Lysosomal alterations are caused by mycobacterial surface components, notably the cell wall-associated lipid sulfolipid-1 (SL-1), which functions through the mTOR complex 1 (mTORC1)-transcription factor EB (TFEB) axis in the host cells. An mutant lacking SL-1, Δ shows attenuated lysosomal rewiring compared with the WT in both and infections. Exposing macrophages to purified SL-1 enhanced the trafficking of phagocytic cargo to lysosomes. Correspondingly, Δ exhibited a further reduction in lysosomal delivery compared with the WT. Reduced trafficking of this mutant strain to lysosomes correlated with enhanced intracellular bacterial survival. Our results reveal that global alteration of the host lysosomal system is a defining feature of -infected macrophages and suggest that this altered lysosomal state protects host cell integrity and contributes to the containment of the pathogen.

}, issn = {1083-351X}, doi = {10.1074/jbc.RA120.012809}, author = {Sachdeva, Kuldeep and Goel, Manisha and Sudhakar, Malvika and Mehta, Mansi and Raju, Rajmani and Raman, Karthik and Singh, Amit and Sundaramurthy, Varadharajan} } @article {78165, title = {Plasmodium vivax liver stage assay platforms using Indian clinical isolates.}, journal = {Malar J}, volume = {19}, year = {2020}, month = {2020 Jun 22}, pages = {214}, abstract = {

BACKGROUND: Vivax malaria is associated with significant morbidity and economic loss, and constitutes the bulk of malaria cases in large parts of Asia and South America as well as recent case reports in Africa. The widespread prevalence of vivax is a challenge to global malaria elimination programmes. Vivax malaria control is particularly challenged by existence of dormant liver stage forms that are difficult to treat and are responsible for multiple relapses, growing drug resistance to the asexual blood stages and host-genetic factors that preclude use of specific drugs like primaquine capable of targeting Plasmodium vivax liver stages. Despite an obligatory liver-stage in the Plasmodium life cycle, both the difficulty in obtaining P. vivax sporozoites and the limited availability of robust host cell models permissive to P. vivax infection are responsible for the limited knowledge of hypnozoite formation biology and relapse mechanisms, as well as the limited capability to do drug screening. Although India accounts for about half of vivax malaria cases world-wide, very little is known about the vivax liver stage forms in the context of Indian clinical isolates.

METHODS: To address this, methods were established to obtain infective P. vivax sporozoites from an endemic region in India and multiple assay platforms set up to detect and characterize vivax liver stage forms. Different hepatoma cell lines, including the widely used HCO4 cells, primary human hepatocytes as well as hepatocytes obtained from iPSC{\textquoteright}s generated from vivax patients and healthy donors were tested for infectivity with P. vivax sporozoites.

RESULTS: Both large and small forms of vivax liver stage are detected in these assays, although the infectivity obtained in these platforms are low.

CONCLUSIONS: This study provides a proof of concept for detecting liver stage P. vivax and provide the first characterization of P. vivax liver stage forms from an endemic region in India.

}, issn = {1475-2875}, doi = {10.1186/s12936-020-03284-8}, author = {Subramani, Pradeep A and Vartak-Sharma, Neha and Sreekumar, Seetha and Mathur, Pallavi and Nayer, Bhavana and Dakhore, Sushrut and Basavanna, Sowmya K and Kalappa, Devaiah M and Krishnamurthy, Ramya V and Mukhi, Benudhar and Mishra, Priyasha and Yoshida, Noriko and Ghosh, Susanta Kumar and Shandil, Radhakrishan and Narayanan, Shridhar and Campo, Brice and Hasegawa, Kouichi and Anvikar, Anupkumar R and Valecha, Neena and Sundaramurthy, Varadharajan} } @article {45300, title = {Influence of midgut microbiota in Anopheles stephensi on Plasmodium berghei infections.}, journal = {Malar J}, volume = {17}, year = {2018}, month = {2018 Oct 25}, pages = {385}, abstract = {

BACKGROUND: The native gut microbiota of Anopheles mosquitoes is known to play a key role in the physiological function of its host. Interestingly, this microbiota can also influence the development of Plasmodium in its host mosquitoes. In recent years, much interest has been shown in the employment of gut symbionts derived from vectors in the control of vector-borne disease transmission. In this study, the midgut microbial diversity has been characterized among laboratory-reared adult Anopheles stephensi mosquitoes, from the colony created by rearing progeny of wild-caught mosquitoes (obtained from three different locations in southern India) for multiple generations, using 16S ribosomal RNA (rRNA) gene sequencing approach. Further, the influence of native midgut microbiota of mosquitoes on the development of rodent malaria parasite Plasmodium berghei in its host has been studied.

METHODS: The microbial diversity associated with the midgut of An. stephensi mosquitoes was studied by sequencing V3 region of 16S ribosomal RNA (rRNA) gene. The influence of native midgut microbiota of An. stephensi mosquitoes on the susceptibility of the mosquitoes to rodent malaria parasite P. berghei was studied by comparing the intensity and prevalence of P. berghei infection among the antibiotic treated and untreated cohorts of mosquitoes.

RESULTS: The analysis of bacterial diversity from the midguts of An. stephensi showed Proteobacteria as the most dominant population among the three laboratory-reared strains of An. stephensi studied. Major genera identified among these mosquito strains were Acinetobacter, Pseudomonas, Prevotella, Corynebacterium, Veillonella, and Bacillus. The mosquito infectivity studies carried out to determine the implication of total midgut microbiota on P. berghei infection showed that mosquitoes whose native microbiota cleared with antibiotics had increased susceptibility to P. berghei infection compared to the antibiotic untreated mosquitoes with its natural native microbiota.

CONCLUSIONS: The use of microbial symbiont to reduce the competence of vectors involved in disease transmission has gained much importance in recent years as an emerging alternative approach towards disease control. In this context, the present study was aimed to identify the midgut microbiota composition of An. stephensi, and its effect on the development of P. berghei. Interestingly, the analysis of midgut microbiota from An. stephensi revealed the presence of genus Veillonella in Anopheles species for the first time. Importantly, the study also revealed the negative influence of total midgut microbiota on the development of P. berghei in three laboratory strains of An. stephensi, emphasizing the importance of understanding the gut microbiota in malaria vectors, and its relationship with parasite development in designing strategies to control malaria transmission.

}, issn = {1475-2875}, doi = {10.1186/s12936-018-2535-7}, author = {Kalappa, Devaiah Monnanda and Subramani, Pradeep Annamalai and Basavanna, Sowmya Kanchanahalli and Ghosh, Susanta Kumar and Sundaramurthy, Varadharajan and Uragayala, Sreehari and Tiwari, Satyanarayan and Anvikar, Anupkumar R and Valecha, Neena} } @article {45310, title = {The Interplay of Host Autophagy and Eukaryotic Pathogens.}, journal = {Front Cell Dev Biol}, volume = {6}, year = {2018}, month = {2018}, pages = {118}, abstract = {

For intracellular pathogens, host cells provide a replicative niche, but are also armed with innate defense mechanisms to combat the intruder. Co-evolution of host and pathogens has produced a complex interplay of host-pathogen interactions during infection, with autophagy emerging as a key player in the recent years. Host autophagy as a degradative process is a significant hindrance to intracellular growth of the pathogens, but also can be subverted by the pathogens to provide support such as nutrients. While the role of host cell autophagy in the pathogenesis mechanisms of several bacterial and viral pathogens have been extensively studied, less is known for eukaryotic pathogens. In this review, we focus on the interplay of host autophagy with the eukaryotic pathogens and the fungal pathogens and . The differences between these eukaryotic pathogens in terms of the host cell types they infect, infective strategies and the host responses required to defend against them provide an interesting insight into how they respond to and interact with host cell autophagy. Due to the ability to infect multiple host species and cell types during the course of their usually complex lifestyles, autophagy plays divergent roles even for the same pathogen. The scenario is further compounded since many of the eukaryotic pathogens have their own sets of either complete or partial autophagy machinery. Eukaryotic pathogen-autophagy interplay is thus a complex relationship with many novel insights for the basic understanding of autophagy, and potential for clinical relevance.

}, issn = {2296-634X}, doi = {10.3389/fcell.2018.00118}, author = {Evans, Robert J and Sundaramurthy, Varadharajan and Frickel, Eva-Maria} } @article {28253, title = {Survival of Mycobacterium tuberculosis and Mycobacterium bovis BCG in lysosomes in~vivo.}, journal = {Microbes Infect}, volume = {19}, year = {2017}, month = {2017 Nov}, pages = {515-526}, abstract = {

Mycobacterium tuberculosis is one of the most successful pathogens known, having infected more than a third of the global population. An important strategy for intracellular survival of pathogenic mycobacteria relies on their capacity to resist delivery to lysosomes, instead surviving within macrophage phagosomes. Several factors of both mycobacterial and host origin have been implicated in this process. However, whether or not this strategy is employed in\ vivo is not clear. Here we show that in\ vivo, following intravenous infection, M. tuberculosis and Mycobacterium bovis BCG initially survived by resisting lysosomal transfer. However, after prolonged infection the bacteria were transferred to lysosomes yet continued to proliferate. A M. bovis BCG mutant lacking protein kinase G (PknG), that cannot avoid lysosomal transfer and is readily cleared in\ vitro, was found to survive and proliferate in\ vivo. The ability to survive and proliferate in lysosomal organelles in\ vivo was found to be due to an altered host environment rather than changes in the inherent ability of the bacteria to arrest phagosome maturation. Thus, within an infected host, both M. tuberculosis and M. bovis BCG adapts to infection-specific host responses. These results are important to understand the pathology of tuberculosis and may have implications for the development of effective strategies to combat tuberculosis.

}, issn = {1769-714X}, doi = {10.1016/j.micinf.2017.06.008}, author = {Sundaramurthy, Varadharajan and Korf, Hannelie and Singla, Ashima and Scherr, Nicole and Nguyen, Liem and Ferrari, Giorgio and Landmann, Regine and Huygen, Kris and Pieters, Jean} }