Mansour Mohamadzadeh’s research while affiliated with The University of Texas at San Antonio and other places

Glutamine metabolism is essential for T cell activation and functions. The inhibition of glutaminolysis impairs Th17 cell differentiation and alters Th1 cell functions. There is evidence for an active glutaminolysis in the immune cells of lupus patients. Treatment of lupus-prone mice with glutaminolysis inhibitors ameliorated disease in association with a reduced frequency of Th17 cells. This study was performed to determine the role of glutaminolysis in murine Tfh cells, a critical subset of helper CD4 ⁺ T cells in lupus that provide help to autoreactive B cells to produce autoantibodies. We showed that lupus Tfh present a high level of glutamine metabolism. The pharmacological inhibition of glutaminolysis with DON had little effect on the Tfh cells of healthy mice, but it reduced the expression of the critical costimulatory molecule ICOS on lupus Tfh cells, in association with a reduction of autoantibody production, germinal center B cell dynamics, as well as a reduction of the frequency of atypical age-related B cells and plasma cells. Accordingly, profound transcriptomic and metabolic changes, including an inhibition of glycolysis, were induced in lupus Tfh cells by DON, while healthy Tfh cells showed little changes. The T cell-specific inhibition of glutaminolysis by deletion of the gene encoding for the glutaminase enzyme GLS1 largely phenocopied the effects of DON on Tfh cells and B cells in an autoimmune genetic background with little effect in a congenic control background. These results were confirmed in an induced model of lupus. Finally, we showed that T cell-specific Gls1 deletion impaired T- dependent humoral responses in autoimmune mice as well as their Tfh response to a viral infection. Overall, these results demonstrated a greater intrinsic requirement of lupus Tfh cells for their helper functions, and they suggest that targeting glutaminolysis may be beneficial to treat lupus.

Systemic lupus erythematosus (SLE) is an autoimmune disease in which the production of pathogenic autoantibodies depends on T follicular helper (TFH) cells. This study was designed to investigate the mechanisms by which inhibition of glycolysis with 2-deoxy-d-glucose (2DG) reduces the expansion of TFH cells and the associated autoantibody production in lupus-prone mice. Integrated cellular, transcriptomic, epigenetic and metabolic analyses showed that 2DG reversed the enhanced cell expansion and effector functions, as well as mitochondrial and lysosomal defects in lupus TFH cells, which include an increased chaperone-mediated autophagy induced by TLR7 activation. Importantly, adoptive transfer of 2DG-reprogrammed TFH cells protected lupus-prone mice from disease progression. Orthologs of genes responsive to 2DG in murine lupus TFH cells were overexpressed in the TFH cells of SLE patients, suggesting a therapeutic potential of targeting glycolysis to eliminate aberrant TFH cells and curb the production of autoantibodies inducing tissue damage.

Objectives were to assess differences in uterine microbiome associated with clinical cure and pregnancy outcomes in dairy cows treated for metritis. Cows with metritis (reddish-brownish, watery, and fetid vaginal discharge) were paired with cows without metritis based on parity and days postpartum. Uterine contents were collected through transcervical lavage at diagnosis, five days later following antimicrobial therapy (day 5), and at 40 days postpartum. Uterine microbiome was assessed by sequencing the V4 hypervariable region of the 16S rRNA gene. Although alpha-diversity based on Chao1, Shannon, and inverse Simpson indexes at diagnosis did not differ between cows with and without metritis, disease was associated with differences in beta-diversity. Prevalence of Porphyromonas, Bacteroides, and Veillonella was greater in cows with metritis. Streptococcus, Sphingomonas, and Ureaplasma were more prevalent in cows without metritis. Differences in beta-diversity between cows with and without metritis persisted on day 5. Uterine microbiome was not associated with clinical cure. Richness and alpha-diversity, but not beta-diversity, of uterine microbiome 40 days postpartum were associated with metritis and pregnancy. No relationship between uterine microbiome and pregnancy outcomes was observed. Results indicate that factors other than changes in intrauterine bacterial community underlie fertility loss and clinical cure in cows with metritis.

The maintenance of regulatory T (T reg ) cells critically prevents autoimmunity. Pre–B cell leukemia transcription factor 1 ( Pbx1 ) variants are associated with lupus susceptibility, particularly through the expression of a dominant negative isoform Pbx1-d in CD4 ⁺ T cells. Pbx1-d overexpression impaired T reg cell homeostasis and promoted inflammatory CD4 ⁺ T cells. Here, we showed a high expression of Pbx1 in human and murine T reg cells, which is decreased in lupus patients and mice. Pbx1 deficiency or Pbx1-d overexpression reduced the number, stability, and suppressive activity of T reg cells, which increased murine responses to immunization and autoimmune induction. Mechanistically, Pbx1 deficiency altered the expression of genes implicated in cell cycle and apoptosis in T reg cells. Intriguingly, Rtkn2 , a Rho-GTPase previously associated with T reg homeostasis, was directly transactivated by Pbx1. Our results suggest that the maintenance of T reg cell homeostasis and stability by Pbx1 through cell cycle progression prevent the expansion of inflammatory T cells that otherwise exacerbates lupus progression in the hosts.

Ischemic stroke is the second leading cause of death and disability worldwide, and efforts to prevent stroke, mitigate secondary neurological damage, and promote neurological recovery remain paramount. Recent findings highlight the critical importance of microbiome-related metabolites, including vitamin B12 (VB12), in alleviating toxic stroke-associated neuroinflammation. Here, we showed that VB12 tonically programmed genes supporting microglial cell division and activation and critically controlled cellular fatty acid metabolism in homeostasis. Intriguingly, VB12 promoted mitochondrial transcriptional and metabolic activities and significantly restricted stroke-associated gene alterations in microglia. Furthermore, VB12 differentially altered the functions of microglial subsets during the acute phase of ischemic stroke, resulting in reduced brain damage and improved neurological function. Pharmacological depletion of microglia before ischemic stroke abolished VB12-mediated neurological improvement. Thus, our preclinical studies highlight the relevance of VB12 in the functional programming of microglia to alleviate neuroinflammation, minimize ischemic injury, and improve host neurological recovery after ischemic stroke.

Tryptophan modulates disease activity and the composition of microbiota in the B6.Sle1.Sle2.Sle3 (TC) mouse model of lupus. To directly test the effect of tryptophan on the gut microbiome, we transplanted fecal samples from TC and B6 control mice into germ-free or antibiotic-treated non-autoimmune B6 mice that were fed with a high or low tryptophan diet. The recipient mice with TC microbiota and high tryptophan diet had higher levels of immune activation, autoantibody production and intestinal inflammation. A bloom of Ruminococcus gnavus (Rg), a bacterium associated with disease flares in lupus patients, only emerged in the recipients of TC microbiota fed with high tryptophan. Rg depletion in TC mice decreased autoantibody production and increased the frequency of regulatory T cells. Conversely, TC mice colonized with Rg showed higher autoimmune activation. Overall, these results suggest that the interplay of genetic and tryptophan can influence the pathogenesis of lupus through the gut microbiota.

Aim To evaluate the effect of different oral irrigators on the sub‐gingival microbiome composition in patients with naturally occurring plaque‐induced gingivitis. Materials and Methods Sub‐gingival plaque was collected from adults participating in a clinical trial assessing the efficacy of oral hygiene with two different oral irrigators (Waterpik Water Flosser [Group 1] and Oral‐B Water Flosser [Group 2]) versus dental flossing (Group 3) for microbiome analysis. Plaque samples were reflective of naturally occurring plaque‐induced gingivitis at baseline and of gingival health at the endpoint (4 weeks). Clinical measures of gingival inflammation were collected, and the sub‐gingival microbiome was analysed by 16S rRNA sequencing to identify amplicon sequence variants. Results Oral hygiene instruction with self‐performed manual toothbrushing and water‐jet irrigation led to significant reductions in inflammation for all groups; both oral irrigators outperformed flossing in bleeding‐on‐probing reduction ( p < .001). Microbiome diversity of sub‐gingival plaque remained relatively stable over time, but significant changes were noted in certain taxa, consistent with increases in the relative abundance of commensals and reductions in late colonizers and periodontal pathogens in the water‐jet groups. Conclusions Reduction in gingival inflammation at 4 weeks within the water‐jet groups is accompanied by slight but critical changes in microbiome composition. Although biodiversity does not substantially change within 4 weeks during the resolution of naturally induced gingivitis, significant relative increases in commensal early colonizers such as Streptococcus , Veillonella and Fusobacterium were accompanied by a shift towards a less anaerobic microbiota associated with return to health. These changes were contingent upon the type of interdental hygiene, with Group 1 exhibiting more significant alterations in microbiome composition towards a periodontal‐health‐compatible community.