Biology subjects

Thackray, V. G.

Publications and source records attributed to Thackray, V. G..

5 recordsLinked to original sources

bioRxiv2025

Toll-like Receptor 4 Contributes to PCOS-like Metabolic and Reproductive Pathogenesis

Polycystic ovary syndrome (PCOS) is a reproductive disorder with heterogeneous symptoms and severity. Despite extensive research documenting chronic immune dysfunction as a hallmark of PCOS, the specific molecular mechanisms driving immune activation and its connection to the syndromes diverse symptoms remain poorly understood. Emerging evidence suggests that gut-derived bacterial endotoxins, particularly lipopolysaccharide (LPS), may breach the intestinal barriers in PCOS patients and trigger systemic inflammation through Toll-like receptor 4 (TLR4), a pattern recognition receptor of the innate immune system. This study investigated whether TLR4 serves as a critical mechanistic driver of PCOS pathogenesis by examining the effect of genetic TLR4 knockout (TLR4-/-) in a letrozole (LET)-induced mouse model of PCOS. Our results demonstrate that TLR4 deficiency reduces many PCOS-like symptoms, including elevated luteinizing hormone, anovulation, and metabolic dysfunction. TLR4 knockout also preserved estrous cycling and fertility, improved glucose tolerance, maintained gut barrier integrity, and reduced inflammatory markers in LET-treated females. These findings establish TLR4 as a key mediator orchestrating PCOSs multi-system pathology, positioning TLR4 as a critical convergence point rather than affecting individual symptoms in isolation. This novel work reveals that TLR4-mediated inflammation drives multiple PCOS pathologies, opening avenues for targeted anti-inflammatory treatments in women with this disorder. Significance StatementPolycystic ovary syndrome (PCOS) affects up to 15% of reproductive-age women worldwide. This study reveals that TLR4, an innate immune receptor, is key to the pathophysiology of PCOS-like symptoms in female mice. When TLR4 was genetically deleted, mice treated with letrozole to induce PCOS-like symptoms maintained normal weight, glucose regulation, estrous cycling, and fertility. The improvements coincided with preserved gut barrier breakdown and reduced inflammation. These findings identify TLR4 as a key mediator between gut health, immune activation, and PCOS pathophysiology, suggesting that targeting TLR4 could offer new therapeutic approaches for this common but poorly understood syndrome affecting millions of women.

immunology↗

bioRxiv2025

T cells are necessary for development of PCOS reproductive symptoms in a letrozole-induced mouse model of PCOS

Polycystic ovary syndrome (PMOS) is a complex reproductive disorder with clear genetic susceptibilities that impact the heterogeneous clinical presentation of symptoms and severity through unknown mechanisms. Chronic inflammation is linked to PMOS, but a clear cause-and-effect relationship between immune mediators and PMOS phenotypes has yet to be demonstrated. This study employed a comprehensive systems immunology approach, utilizing a letrozole-induced PMOS mouse model to identify changes in inflammatory factors associated with PMOS symptoms. By analyzing immune cells and secreted cytokines from 22 different mouse strains, we identified T cells and TNF-{beta} as associated with PMOS-like phenotypes, regardless of genetic background. We used a knockout of TCR to show that functional T cells are necessary for development of pathologically elevated luteinizing hormone (LH) in letrozole-treated female mice. In women with PMOS, we observed elevated TNF-{beta} transcripts in immune cells from women with PMOS. Finally, we demonstrate that TNF-{beta} increased Lhb mRNA in a female mouse gonadotrope-derived cell line, suggesting that TNF-{beta} may directly modulate gonadotrope gene expression and may contribute to elevated LH in PMOS-like conditions. These findings support a requirement for functional {beta} T cells in LET-induced LH elevation in a PMOS-like mouse model and identify TNF-{beta} as a candidate immune mediator for further investigation. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=190 SRC="FIGDIR/small/631835v2_ufig1.gif" ALT="Figure 1"> View larger version (90K): org.highwire.dtl.DTLVardef@14dcf2aorg.highwire.dtl.DTLVardef@15bdc67org.highwire.dtl.DTLVardef@1e2f718org.highwire.dtl.DTLVardef@1cc5c16_HPS_FORMAT_FIGEXP M_FIG C_FIG One Sentence SummaryFunctional {beta} T cells are linked to LET-induced LH elevation in a PMOS-like mouse model, uncovering candidate immune mechanisms for further study.

immunology↗

bioRxiv2024

Genetic hypogonadal (Gnrh1 hpg) mouse model uncovers influence of reproductive axis on maturation of the gut microbiome during puberty

The gut microbiome plays a key role in human health and gut dysbiosis is linked to many sex-specific diseases including autoimmune, metabolic, and neurological disorders. Activation of the hypothalamic-pituitary-gonadal (HPG) axis during puberty leads to sexual maturation and development of sex differences through the action of gonadal sex steroids. While the gut microbiome also undergoes sex differentiation, the mechanisms involved remain poorly understood. Using a genetic hypogonadal (hpg) mouse model, we sampled the fecal microbiome of male and female wild-type and hpg mutant mice before and after puberty to determine how microbial taxonomy and function are influenced by age, sex, and the HPG axis. We showed that HPG axis activation during puberty is required for sexual maturation of the gut microbiota composition, community structure, and metabolic functions. We also demonstrated that some sex differences in taxonomic composition and amine metabolism developed independently of the HPG axis, indicating that sex chromosomes are sufficient for certain sex differences in the gut microbiome. In addition, we showed that age, independent of HPG axis activation, led to some aspects of pubertal maturation of the gut microbiota community composition and putative functions. These results have implications for microbiome-based treatments, indicating that sex, hormonal status, and age should be considered when designing microbiome-based therapeutics.

microbiology↗

bioRxiv2023

Hypogonadal (Gnrh1hpg) mice reveal niche-specific influence of reproductive axis and sex on intestinal microbial communities

The gut microbiome has been linked to many diseases with sex bias including autoimmune, metabolic, neurological, and reproductive disorders. Numerous studies report sex differences in fecal microbial communities, but how this differentiation occurs remains unclear. Using a genetic hypogonadal mouse model that does not produce sex steroids or go through puberty, we investigated how sex and the reproductive axis impact bacterial diversity within the small and large intestine. Both sex and reproductive axis inactivation altered bacterial composition in an intestinal section and niche-specific manner. Our results also implicated factors independent of the reproductive axis (i.e., sex chromosomes) in shaping intestinal communities. Additionally, our detailed profile of intestinal communities showed that fecal samples do not reflect bacterial diversity in the small intestine. Our results have ramifications for studying the impact of sex differences on the gut microbiome, particularly in sex-biased diseases and factoring in sex and steroid levels in microbial-based therapies.

microbiology↗

bioRxiv2020

Gut metabolites are more predictive of disease- and cohoused- states than gut bacterial features in a mouse model of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) impacts [~]10% of reproductive-aged women worldwide. In addition to infertility, women with PCOS suffer from metabolic dysregulation which increases their risk of developing type 2 diabetes, cardiovascular disease and non-alcoholic fatty liver disease. Studies have shown differences in the gut microbiome of women with PCOS compared to controls, a pattern replicated in mouse models. Recently, using a letrozole-induced mouse model of PCOS, we demonstrated that cohousing was protective against development of metabolic and reproductive phenotypes and showed via 16S amplicon sequencing that this protection correlated with time-dependent shifts in gut bacteria. Here, we applied untargeted metabolomics and shotgun metagenomics approaches to further analyze the longitudinal samples from the cohousing experiment. Analysis of beta diversity found that untargeted metabolites had the strongest correlation to both disease and cohoused states and that shifts in metabolite diversity were detected prior to shifts in bacterial diversity. In addition, log2-fold analyses found numerous metabolite features, particularly bile acids (BA), to be highly differentiated between placebo (P) and letrozole (LET), as well as cohoused LET versus LET. Our results indicate that changes in gut metabolites, particularly BAs, are associated with a PCOS-like phenotype in the LET mouse model as well as the protective effect of cohousing. Our results also suggest that transfer of metabolites via coprophagy occurs rapidly and may precipitate changes in bacterial diversity. This study joins a growing body of research highlighting changes in primary and secondary bile acids that may provide a link between host metabolism and gut microbes relevant to the pathology of PCOS. IMPORTANCEUsing a combination of untargeted metabolomics and metagenomics, we performed a comparative longitudinal analysis of the feces collected in a cohousing study with a PCOS mouse model. Our results showed that gut metabolite composition experienced earlier and more pronounced differentiation in both the disease model and cohoused mice compared with the microbial composition. Notably, statistical and machine learning approaches identified shifts in the relative abundance of primary and secondary BA, which have been implicated as modifiers of gut microbial growth and diversity. Network correlation analysis showed strong associations between particular BA and bacterial species, particularly members of Lactobacillus, and that these correlations were time and treatment dependent. Our results provide novel insights into host/microbe relationships related to hyperandrogenism in females and indicate that focused research into small molecule control of gut microbial diversity and host physiology may provide new therapeutic options for the treatment of PCOS.

microbiology↗