Background: Severe burns activate systemic inflammation and lead to an increase in cytokine levels. Epigenetic elements are key regulators of inflammation; however, their involvement in severe burns has not been studied. In this work, we aimed to unveil the histone H3 posttranslational modifications (PTM) profile and their enrichment in promoters of inflammatory genes in response to severe burns. Methods: The levels of H3 PTMs were analyzed by ELISA assays in circulating cells from burn patients. ChIP assays were conducted to evaluate the enrichment of H3K9me2 and H3S28p at the promoter of CXCL8, IL-17, TNFA, IL-6, FOS, and IL-1B genes. Results: We found that eight H3 PTMs decreased at 5 days post-burn. Burn patients showed a decreased enrichment of H3K9me2 in CXCL8, IL-17, and TNFA promoters, whereas IL-6, FOS, and IL-1B promoters displayed an H3S28p enrichment diminution during the first 10 days post-burn. Interestingly, burn-injured septic patients exhibited an increased enrichment of H3K9me2 in TNFA, IL-1B, CXCL8, and IL-17 promoters, whereas H3S28p was increased in promoters of TNFA and IL-1B at 1 dpb. Conclusion: Severe burns trigger epigenetic changes and differential H3 PTM enrichment at inflammation gene promoters. Epigenetic misregulation of H3 may be involved in sepsis occurrence after severe burn injury.

Background: Morbid obesity is associated with metabolic alterations and the onset of type 2 diabetes. Patients who undergo a malabsorptive bariatric surgery show an important improvement in several clinical variables and a modification in the gut microbiota balance. In this study, we aimed to identify bacteria related to changes in the body mass index of patients who underwent a bariatric surgery and their relationship with nutrients intake. Results: There were differences in bacterial diversity in the gut microbiota of patients that underwent a bariatric surgery. The Shannon and Simpson indexes decrease after the surgery (p < 0.001) and the beta diversity indexes (Bray-Curtis, Weighted and Unweighted UniFrac) showed differences when comparing pre- and post-surgery (p = 0.001). The abundance of a species in the genus Coprococcus correlated positively with the intake of magnesium and thiamin in post-surgery individuals (rho = 0.816, pFDR = 0.029 and rho = 0.812, pFDR = 0.029, respectively) and was related to BMI in both groups (p = 0.043 pre-surgery and p = 0.036 post-surgery). The abundances of several bacteria belonging to the order Clostridiales, as well as an enrichment of vitamin B1 (thiamin) biosynthesis, sugar degradation, acetate production and some amino acids biosynthesis were higher before the surgery. Conclusions: The abundance of a species of the genus Coprococcus that showed inverse relationships with BMI in pre-surgery and post-surgery patients correlates with the intake of magnesium and thiamin in individuals that underwent a malabsorptive bariatric surgery. It indicates that the well-established beneficial effects of bariatric surgery on BMI may be amplified by modulating the intake of micronutrients and its effect on the gut bacterial.

The slow-growing, nontuberculous mycobacterium Mycobacterium kumamotonense possesses two rRNA operons, rrnA and rrnB, located downstream from the murA and tyrS genes, respectively. Here, we report the sequence and organization of the promoter regions of these two rrn operons. In the rrnA operon, transcription can be initiated from the two promoters, named P1 rrnA and PCL1, while in rrnB, transcription can only start from one, called P1 rrnB. Both rrn operons show a similar organization to the one described in Mycobacterium celatum and Mycobacterium smegmatis. Furthermore, by qRT-PCR analyses of the products generated from each promoter, we report that stress conditions such as starvation, hypoxia, and cellular infection affect the contribution of each operon to the synthesis of pre-rRNA. It was found that the products from the PCL1 promoter of rrnA play a pivotal role in rRNA synthesis during all stress conditions. Interestingly, the main participation of the products of transcription from the P1 promoter of rrnB was found during hypoxic conditions at the NRP1 phase. These results provide novel insights into pre-rRNA synthesis in mycobacteria, as well as the potential ability of M. kumamotonense to produce latent infections.