Testing the hypothesis that Human Beta Defensin-2 induces dormancy in Mycolicibacterium smegmatis, a model organism for Mycobacterium tuberculosis 3762

Abstract Description The innate immune system, including mucosal epithelial defenses, is vital in combatting microbial invasions. Epithelial cells contribute to this by producing antimicrobial peptides, like Human Beta Defensin-2 (HBD2). We aim to understand how HBD2 affects Mycolicibacterium smegmatis (Ms), a model organism for Mycobacterium tuberculosis (Mtb), the leading cause of tuberculosis (TB). With millions affected by TB yearly and rising drug resistance, novel treatments are needed. Our previous work suggests that HBD2 inhibits Ms’ metabolic activity at low concentrations without killing it. This study explored whether HBD2 induces dormancy in Ms by quantifying the expression of the dormancy-regulated genes Rv2031c, Rv3131, and Rv3133c and the reference gene 16S rRNA using RT-qPCR and SYBR green technology in HBD2 treated bacteria compared to untreated bacteria. Hypoxic conditions known to induce dormancy in Ms served as a positive control for dormancy induction. RNA was extracted, reverse transcribed to cDNA, and analyzed. Interestingly, methylene blue, used to confirm hypoxia, appeared to stabilize the RNA, improving mRNA quality. Preliminary data show upregulation of dormancy-related genes under hypoxia and suggest that HBD2 treatment at 0.3125 µM may induce upregulation of Rv2031c and Rv3131 at about two and four-fold, respectively. This research can lead to novel strategies for TB treatment by inducing bacterial dormancy to control latent infections. Funding Sources Supported by National Science Foundation and CSU-Louis Stokes Alliance for Minority Participation (LSAMP) Grant #HRD-2204753 and Grant #HRD-1826490; Sean Cheng Donation. Topic Categories Microbial, Parasitic, and Fungal Immunology (MPF)