Biology subjects

Mohapatra, S. S.

Publications and source records attributed to Mohapatra, S. S..

5 recordsLinked to original sources

bioRxiv2026

Glomerular-Targeted Delivery of Low-Dose Prednisolone Attenuates Established Lupus Nephritis in MRL/lpr Mice.

BackgroundLupus nephritis remains a major cause of chronic kidney disease and kidney failure in systemic lupus erythematosus. Glucocorticoids are central to treatment but are limited by systemic toxicity. We evaluated whether a previously characterized collagen IV 3-targeted liposomal nanoparticle formulation carrying low-dose prednisolone could attenuate established lupus nephritis in MRL/lpr mice. MethodsFemale MRL/lpr mice with disease present at treatment initiation and C57BL/6J control mice received saline or collagen IV 3-targeted prednisolone-loaded nanoparticles (Col4-3-Pred-NPs). Renal outcomes were assessed by longitudinal proteinuria, glomerular filtration rate (GFR), survival, kidney histopathology, renal IgG and C3d deposition, dUTP/TUNEL-associated injury staining, and renal cytokine/chemokine profiling. Body weight, food and water intake, and blood glucose were monitored as measures of general condition and preliminary tolerability. ResultsCol4-3-Pred-NPs improved survival in MRL/lpr mice, reduced cumulative proteinuria burden, and attenuated terminal GFR decline compared with saline-treated MRL/lpr controls. Treatment reduced glomerular and tubulointerstitial injury, lowered composite EGTI histopathology scores, decreased terminal kidney enlargement, reduced glomerular IgG deposition and renal dUTP-positive injury signals, and reduced renal signals for IL-28A/B, IL-7, PD-ECGF, IL-11, CCL6/C10, and IL-15. C3d deposition was not significantly altered. Nanoparticle treatment was not associated with sustained treatment-related increases in blood glucose or body-weight loss during the measured study period. ConclusionsCollagen IV 3-targeted liposomal delivery of low-dose prednisolone attenuated established lupus nephritis in MRL/lpr mice and improved renal structural, functional, inflammatory, and survival outcomes. These findings support further evaluation of glomerulus-targeted nanotherapy as a potential strategy to improve the precision and therapeutic index of glucocorticoid treatment in lupus nephritis.

physiology↗

bioRxiv2026

Insights into the Klebsiella pneumoniae adaptive response mechanisms to colistin exposure using a label-free quantitative proteomics approach

The rise of MDR Klebsiella pneumoniae and its resistance to the last-resort antibiotic colistin poses a significant threat to global healthcare. While genomic studies have identified several resistance mutations, the transient proteomic shifts that occur during the initial exposure of sensitive strains to lethal antibiotic doses remain poorly characterised. In this study, we employed a label-free quantitative proteomics approach to investigate the protein expression profile of K. pneumoniae strain ATCC 13883 treated with colistin at its MIC. Membrane proteins were extracted at critical growth stages, and differentially abundant proteins (DAPs) were analysed using Gene Ontology and KEGG pathway enrichment analysis. Our proteomic analysis identified 718 DAPs (339 upregulated and 379 downregulated). The cellular response was characterised primarily by outer membrane remodelling and a significant upregulation of the capsule-associated kinase Wzc and the ArnBCADTEF operon, which facilitates lipid A modification with L-Ara4N moiety. Paradoxically, while RND-family efflux pumps (AcrAB) were significantly induced, the global activator RamA and major porins (OmpA, OmpX, LamB) were downregulated, possibly to minimise antibiotic entry. KEGG pathway enrichment analysis further revealed a synchronised metabolic shift, characterised by an intensified TCA cycle flux to fuel high-energy resistance processes despite a general slowdown in carbohydrate metabolism. Our findings demonstrate that K. pneumoniae responds to colistin stress through a rapid, multifaceted proteomic reorganisation involving charge neutralisation, structural reinforcement of the cell envelope, and metabolic re-routing. These results provide a molecular blueprint of the early adaptive response, identifying several proteins as potential therapeutic targets.

microbiology↗

bioRxiv2024

Fitness trade-off and the discovery of a novel missense mutation in the PmrB sensor kinase of a colistin-resistant Pseudomonas aeruginosa strain developed by adaptive laboratory evolution

Pseudomonas aeruginosa is a prominent bacterial pathogen that causes several nosocomial infections and is notorious for its environmental resilience and rapid development of resistance to frontline antibiotics. A major cause of mortality and morbidity among cystic fibrosis patients, multidrug-resistant P. aeruginosa is often targeted with the antibiotic colistin as a last option. However, increasing reports of colistin resistance among P. aeruginosa is a matter of significant concern. Though the molecular mechanisms responsible for the development of colistin resistance are well known, the evolutionary trajectory to colistin resistance is an important area of investigation. In this work, using the adaptive laboratory evolution (ALE) approach we have evolved a colistin-sensitive P. aeruginosa ancestral strain to a resistant one. During the process of laboratory evolution in 106 generations, colistin MIC was increased 32-fold. The evolved strain had lower fitness than the ancestral strain as evidenced by a lower growth rate and higher doubling time. Moreover, the evolved strain produced more biofilm and less pyocyanin. Interestingly, the evolved strain showed collateral sensitivity to several antibiotics such as co-trimoxazole, rifampicin, kanamycin, tigecycline, penicillin, ampicillin, and teicoplanin. On analysing various TCS modules involved in the development of colistin resistance a novel missense mutation (V136G) was detected in the PmrB sensor kinase. Bioinformatics prediction indicated that the mutation could be deleterious, though the functionality of the PmrB mutant remains to be validated experimentally.

microbiology↗

bioRxiv2022

Targeting an evolutionarily conserved "E-L-L" motif in the spike protein to develop a small molecule fusion inhibitor against SARS-CoV-2

As newer variants of SARS-CoV-2 continue to pose major threats to global human health and economy, identifying novel druggable antiviral targets is the key towards sustenance. Here, we identify an evolutionary conserved "E-L-L" motif present within the HR2 domain of all human and non-human coronavirus spike (S) proteins that play a crucial role in stabilizing the post-fusion six-helix bundle (6-HB) structure and thus, fusion-mediated viral entry. Mutations within this motif reduce the fusogenicity of the S protein without affecting its stability or membrane localization. We found that posaconazole, an FDA-approved drug, binds to this "E-L-L" motif resulting in effective inhibition of SARS-CoV-2 infection in cells. While posaconazole exhibits high efficacy towards blocking S protein-mediated viral entry, mutations within the "E-L-L" motif rendered the protein completely resistant to the drug, establishing its specificity towards this motif. Our data demonstrate that posaconazole restricts early stages of infection through specific inhibition of membrane fusion and viral genome release into the host cell and is equally effective towards all major variants of concerns of SARS-CoV-2 including beta, kappa, delta, and omicron. Together, we show that this conserved essential "E-L-L" motif is an ideal target for the development of prophylactic and therapeutic interventions against SARS-CoV-2.

biochemistry↗

bioRxiv2021

Inhibition of SARS-CoV-2 spike protein palmitoylation reduces virus infectivity

Spike glycoproteins of almost all enveloped viruses are known to undergo post-translational attachment of palmitic acid moieties. The precise role of such palmitoylation of the spike protein in membrane fusion and infection is not completely understood. Here, we report that palmitoylation of the first five cysteine residues of the c-terminal cysteine-rich domain of the SARS-CoV-2 spike are indispensable for infection and palmitoylation deficient spike mutants are defective in trimerization and subsequent membrane fusion. The DHHC9 palmitoyltransferase interacts with and palmitoylates the spike protein in the ER and Golgi, and knockdown of DHHC9 results in reduced fusion and infection of SARS-CoV-2. Two bis-piperazine backbone-based DHHC9 inhibitors inhibit SARS-CoV-2 spike protein palmitoylation and the resulting progeny virion particles released are defective in fusion and infection. This establishes these palmitoyltransferase inhibitors as potential new intervention strategies against SARS-CoV-2.

molecular biology↗