Biology subjects

Nair, B. G.

Publications and source records attributed to Nair, B. G..

2 recordsLinked to original sources

bioRxiv2026

Natural Compound-Mediated SUMOylation Rewires Host Immunity Against Klebsiella pneumoniae

Klebsiella pneumoniae is a major cause of multidrug-resistant and hypervirulent infections worldwide, highlighting the urgent need for host-directed therapeutic strategies that complement conventional antibiotics. Emerging evidence suggests that K. pneumoniae promotes intracellular persistence by suppressing host SUMOylation, a reversible post-translational modification that regulates protein stability, cellular signaling, and innate immune response. This decrease in SUMOylation perturbs NF-{kappa}B signaling, leading to dysregulation of inflammation that promotes bacterial survival, rather than effective immune clearance. Clove Bud Oil (CBO), a natural product derived from Syzygium aromaticum, has previously been shown to possess anti-virulence as well as immunomodulatory properties. In this regard, we investigated the capability of CBO to restore host SUMOylation and enhance innate immune response during infection with classical as well as hypervirulent K. pneumoniae. In macrophages, classical and hypervirulent K. pneumoniae impaired global host SUMOylation, disrupting IKK{beta}-RelA/NF-{kappa}B signalling and uncoupling inflammatory regulation from effective antimicrobial defense to facilitate intracellular persistence. CBO restored SUMOylation-dependent immune homeostasis by attenuating sustained IKK{beta} phosphorylation and degradation, thereby constraining aberrant RelA nuclear translocation, rebalancing pro-inflammatory cytokine responses, and restricting intracellular bacterial survival. These findings demonstrate that restoration of host SUMOylation acts as a key driver of the immunomodulatory activity of CBO, leading to coordinated innate immune responses and enhanced intracellular bacterial clearance. Collectively, our study identifies host SUMOylation as a critical pathway targeted during K. pneumoniae infection and highlights restoration of SUMOylation-mediated immune homeostasis as a promising host-directed therapeutic strategy against multidrug-resistant and hypervirulent K. pneumoniae.

immunology↗

bioRxiv2021

Can proteomics of snake venoms help drug discovery? A study on the venom of spectacled cobra (Naja naja) from the Western Ghats

Venom proteome profiling of Naja naja from the Western Ghats region in Kerala was achieved through SDS-PAGE and RP-HPLC followed by Q-TOF LC-MS/MS analysis, incorporating PEAKS and Novor assisted de novo sequencing methodologies. A total of 115 proteins distributed across 17 different enzymatic and non-enzymatic venom protein families were identified through conventional and 39 peptides through homology-driven proteomics approaches. Fourteen peptides derived through de novo complements the Mascot data indicating the importance of homology-driven approaches in improving protein sequence information. Among the protein families identified, glutathione peroxidase and endonuclease were reported for the first time in the Indian cobra venom. Immunological cross-reactivity assessed using Indian polyvalent antivenoms suggested that VINS showed better EC50 (2.48 g/mL) value than that of PSAV (6.04 g/mL) and Virchow (6.03 g/mL) antivenoms. Western blotting experiments indicated that all the antivenoms elicited poor binding specificities, especially towards low molecular mass proteins. Second-generation antivenomics studies revealed that VINS antivenom was less efficient to detect many low molecular mass proteins such as three-finger toxins and Kunitz-type serine protease Inhibitors. Taken together, the present study enabled a large-scale characterization of the venom proteome of Naja naja from the Western Ghats and emphasized the need for developing more efficient antivenoms. HighlightsO_LIProteomics of cobra venom resulted in the identification of 115 proteins representing 17 snake venom protein families. C_LIO_LIDe novo approaches exclusively yielded 39 peptides harbouring multiple amino acid mutations. C_LIO_LIGlutathione peroxidase and endonuclease were identified for the first time in Indian cobra venom. C_LIO_LIIndian polyvalent antivenoms showed varying cross-reactivity towards cobra venom. C_LIO_LIVINS antivenom was less efficient to detect many low molecular mass proteins (< 20 kDa). C_LI

pharmacology and toxicology↗