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Chinnappan, M.

Publications and source records attributed to Chinnappan, M..

2 recordsLinked to original sources

Androgens at the skin surface regulate S. aureus pathogenesis through the activation of agr quorum sensing

Staphylococcus aureus, the most frequent cause of skin infections, is more common in men than women and selectively colonizes the skin during inflammation. Yet, the specific cues that drive infection in these settings remain unclear. Here we show that the host androgens testosterone and dihydrotestosterone promote S. aureus pathogenesis and skin infection. Without the secretion of these hormones, skin infection in vivo is limited. Testosterone activates S. aureus virulence in a concentration dependent manner through stimulation of the agr quorum sensing system, with the capacity to circumvent other inhibitory signals in the environment. Taken together, our work defines a previously uncharacterized inter-kingdom signal between the skin and the opportunistic pathogen S. aureus and identifies the mechanism of sex-dependent differences in S. aureus skin infection. One-Sentence SummaryTestosterone promotes S. aureus pathogenesis through activation of the agr quorum sensing system.

microbiology↗

Interaction of dengue NS3 with human RNA silencing machinery through HSPA1A

Viruses encode multiple proteins that interact with different host factors to aid in their establishment inside the host. Viral Suppressor of RNA silencing (VSR) are one such class of proteins that have been shown to interact with components of host machinery involved in post transcriptional gene silencing, a known antiviral defence mechanism. In the present study, we showed that dengue NS3, a known VSR not only interacts with HSPA1A, a cellular chaperone, but also modulates its expression levels. Further, we revealed HSPA1A associated with host RNA silencing machinery through its interaction with Argonaute proteins; Ago1, Ago2 and co-localizes with them in the cytoplasm of the cell. Together, these results provide evidence for involvement of other host partners in mediating VSR function of dengue NS3 and aid in deeper understanding of mechanisms underlying viral suppression of RNA silencing.

molecular biology↗