Sexual dimorphism in immunometabolism and autoimmunity: Impact on personalized medicine

A cross-sectional National Health and Nutrition Examination survey-based study of the association between systemic immune-inflammation index and blood urea nitrogen levels in United States adolescents

Blood urea nitrogen (BUN) level is one of the commonly used indicators to assess renal function and systemic immune-inflammatory status. In the adolescent population, changes in BUN levels may be associated with a variety of factors, including physiologic dehydration, lifestyle influences such as nutritional intake, physical activity, and possible endocrine or metabolic disorders. In recent years, more and more studies have shown that BUN levels are not only a reflection of kidney function, but it may also be related to the inflammatory state of the body. The Systemic Immune Inflammatory Index (SII) is a comprehensive index that takes into account platelet counts, neutrophil and lymphocyte counts, and is thought to be effective in reflecting the body's immune status and inflammatory response. However, research on the relationship between the two, SII and BUN, remains understudied in the adolescent population. The purpose of this study was to examine the relationship between SII and BUN levels in a population of American adolescents and to further analyze the factors that influence it. We conducted a cross-sectional study using data from the National Health and Nutrition Examination Survey (NHANES) database. Using descriptive statistics, correlation analysis, and regression analysis, we explored the relationship between SII and BUN levels. We found a significant negative correlation between SII and BUN levels, with BUN levels decreasing when SII levels increased (BUN as the dependent variable and SII as the outcome variable). We performed a multiple regression analysis of this relationship, controlling for possible confounders such as gender, age, race, and BMI, and found that this negative correlation remained significant. Our findings reveal an important relationship between SII and BUN levels and provide new perspectives for understanding adolescent health.

Peripheral Blood Cells From Older Adults Exhibit Sex-Associated Differences in Mitochondrial Function

Blood-based mitochondrial bioenergetic profiling is a feasible, economical, and minimally invasive approach that can be used to examine mitochondrial function and energy metabolism in human subjects. In this study, we use 2 complementary respirometric techniques to evaluate mitochondrial bioenergetics in both intact and permeabilized peripheral blood mononuclear cells (PBMCs) and platelets to examine sex dimorphism in mitochondrial function among older adults. Employing equal numbers of PBMCs and platelets to assess mitochondrial bioenergetics, we observe significantly higher respiration rates in female compared to male participants. Mitochondrial bioenergetic differences remain significant after controlling for independent parameters including demographic parameters (age, years of education), and cognitive parameters (mPACC5, COGDX). Our study illustrates that circulating blood cells, immune cells in particular, have distinctly different mitochondrial bioenergetic profiles between females and males. These differences should be taken into account as blood-based bioenergetic profiling is now commonly used to understand the role of mitochondrial bioenergetics in human health and aging.

Astrocytes at the intersection of ageing, obesity, and neurodegeneration

Once considered passive cells of the central nervous system (CNS), glia are now known to actively maintain the CNS parenchyma; in recent years, the evidence for glial functions in CNS physiology and pathophysiology has only grown. Astrocytes, a heterogeneous group of glial cells, play key roles in regulating the metabolic and inflammatory landscape of the CNS and have emerged as potential therapeutic targets for a variety of disorders. This review will outline astrocyte functions in the CNS in healthy ageing, obesity, and neurodegeneration, with a focus on the inflammatory responses and mitochondrial function, and will address therapeutic outlooks.

Trends in experimental autoimmune prostatitis: insights into pathogenesis, therapeutic strategies, and redefinition

Chronic prostatitis/chronic pelvic pain syndrome (CP/CPSS) is a debilitating condition characterized by prostate inflammation, pain and urinary symptoms. The immune system's response to self-antigens is a contributing factor to CP/CPSS. In this review, we examine the use of experimental autoimmune prostatitis (EAP) in rodents to model salient features of autoimmune mediated CP/CPSS. By exploring etiological factors, immunological mechanisms, and emerging therapeutic strategies, our aim is to enhance our understanding of CP/CPSS pathogenesis and promote the development of strategies to test innovative interventions using the EAP pre-clinical model.

The immunometabolic function of VGLL3 and female-biased autoimmunity

Autoimmune diseases exhibit a pronounced yet unexplained prevalence among women. Vestigial-like family member 3 (VGLL3), a female-biased factor that promotes autoimmunity, has recently been discovered to assist cells in sensing and adapting to nutritional stress. This role of VGLL3 may confer a selective advantage during the evolution of placental mammals. However, the excessive activation of the VGLL3-mediated energy-sensing pathway can trigger inflammatory cell death and the exposure of self-antigens, leading to the onset of autoimmunity. These observations have raised the intriguing perspective that nutrient sensing serves as a double-edged sword in immune regulation. Mechanistically, VGLL3 intersects with Hippo signaling and activates multiple downstream, immune-associated genes that play roles in metabolic regulation. Understanding the multifaceted roles of VGLL3 in nutrient sensing and immune modulation provides insight into the fundamental question of sexual dimorphism in immunometabolism and sheds light on potential therapeutic targets for autoimmune diseases.

Evolutionary relationship between antimitochondrial antibody positivity and primary biliary cholangitis in Taiwan: a 16-year hospital cohort study

Background

How antimitochondrial antibody (AMA)-positive patients evolve to have primary biliary cholangitis (PBC) in viral hepatitis-endemic areas is unknown.

Objectives

We aimed to investigate this evolution in Taiwan.

Design/methods

A 16-year medical center-based cohort study of 2,095,628 subjects was conducted in Taiwan, an Asian country endemic to viral hepatitis. AMA-positive subjects were those with positive AMA with alkaline phosphatase (ALP) ⩽1.5 times the upper limit of normal (ULN), and PBC was defined as positive AMA with ALP >1.5 × ULN.

Results

AMA-positive subjects had a lower average age- and sex-adjusted prevalence than PBC patients (4.68/105 versus 11.61/105, p = 0.0002), but their incidence was comparable (0.99/105 versus 1.12/105, p = 0.36). The former group had a borderline significantly lower mean age (56.59 years versus 58.10 years, p = 0.06) and a lower female-to-male ratio (2.85:1 versus 5.44:1, p < 0.0001). Both AMA-positive subjects (prevalence change: 20.0%, p < 0.01; incidence change: -9.2%, p < 0.01) and PBC patients (prevalence change: 14.6%, p < 0.01; incidence change: -4.7%, p < 0.01) prevalence rate increased but the incidence rate decreased. Among the 423 AMA-positive subjects, 77 (18.2%) developed PBC, for a mean duration of 1.757 years. Compared with AMA-positive subjects, PBC patients had similar concurrent chronic hepatitis B (CHB) rates (2.7% versus 4.3%, p = 0.197) but lower chronic hepatitis C (CHC) rates (3.69% versus 15.60%, p < 0.01).

Conclusion

PBC was more prevalent than AMA-positive subjects, and PBC patients had a higher female-to-male ratio than AMA-positive subjects, of whom 18.2% developed PBC (mean lag: 1.757 years). Upward trends in prevalence rates and downward trends in incidence rates were noted for both AMA-positive subjects and PBC. CHB was rare, CHC was more prevalent among PBC patients than the general population, and CHC was less prevalent among PBC than among AMA-positive subjects.

Deciphering the relationship between temperature and immunity

Fever is a hallmark symptom of disease across the animal kingdom. Yet, despite the evidence linking temperature fluctuation and immune response, much remains to be discovered about the molecular mechanisms governing these interactions. In patients with rheumatoid arthritis, for instance, it is clinically accepted that joint temperature can predict disease progression. But it was only recently demonstrated that the mitochondria of stimulated T cells can rise to an extreme 50°C, potentially indicating a cellular source of these localized 'fevers'. A challenge to dissecting these mechanisms is a bidirectional interplay between temperature and immunity. Heat shock response is found in virtually all organisms, activating protective pathways when cells are exposed to elevated temperatures. However, the temperature threshold that activates these pathways can vary within the same organism, with human immune cells, in particular, demonstrating differential sensitivity to heat. Such inter-cellular variation may be clinically relevant given the small but significant temperature differences seen between tissues, ages, and sexes. Greater understanding of how such small temperature perturbations mediate immune responses may provide new explanations for persistent questions in disease such as sex disparity in disease prevalence. Notably, the prevalence and severity of many maladies are rising with climate change, suggesting temperature fluctuations can interact with disease on multiple levels. As global temperatures are rising, and our body temperatures are falling, questions regarding temperature-immune interactions are increasingly critical. Here, we review this aspect of environmental interplay to better understand temperature's role in immune variation and subsequent risk of disease.

Sex differences in antioxidant ability and energy metabolism level resulting in the difference of hypoxia tolerance in red swamp crayfish (Procambarus clarkii)

Sexual dimorphism widely exists in crustaceans. However, sex differences in the hypoxia tolerance of crayfish have rarely been reported. In this study, the differences in hypoxia tolerance between the two sexes of crayfish were assessed according to mortality, pathological features of hepatopancreas, antioxidant enzyme activity and differentially expressed genes (DEGs) analysis using transcriptome. The results showed that male crayfish displayed significantly higher mortality than the female under hypoxia stress (p < 0.05). Furthermore, female crayfish demonstrated higher levels of antioxidant enzyme activity. Hematoxylin-eosin staining analysis revealed that the damage of hepatopancreas was more severe in the male crayfish compared to the female crayfish. Additionally, there was higher expression level of the DEGs in hypoxia-inducible factor (HIF) pathway and higher energy metabolism level in the female compared to the male. Together, these findings suggest that the female crayfish with higher antioxidant ability and energy metabolism level exhibits stronger hypoxia tolerance than the male crayfish, providing the theoretical support for investigating sex differences in hypoxia tolerance among crustaceans.

No evidence of genetic causal association between sex hormone-related traits and systemic lupus erythematosus: A two-sample Mendelian randomization study

OBJECTIVE

Previous studies have demonstrated an association between sex hormone-related traits and systemic lupus erythematosus (SLE). However, because of the difficulties in determining sequential temporality, the causal association remains elusive. In this study, we used two-sample Mendelian randomization (MR) to explore the genetic causal associations between sex hormone-related traits and SLE.

METHODS

We used a two-sample MR to explore the causal association between sex hormone-related traits and SLE. The summarized data for sex hormone-related traits (including testosterone, estradiol (E2), sex hormone-binding globulin (SHBG), and bioavailable testosterone (BT)) originated from large genome-wide association studies (GWASs) of European descent. Aggregated data for SLE were derived from the FinnGen consortium (835 cases and 300,162 controls). Random-effects inverse-variance weighted (IVW), MR-Egger, weighted median, simple mode, weighted mode, and fixed-effects IVW methods were used for the MR analysis. Random-effects IVW was the primary method used to analyze the genetic causal association between sex hormone-related traits and SLE. Heterogeneity of the MR results was detected using the IVW Cochran's Q estimates. The pleiotropy of MR results was detected using MR-Egger regression and the MR pleiotropy residual sum and outlier (MR-PRESSO) test. Finally, leave-one-out analysis was performed to determine whether MR results were affected by a single single-nucleotide polymorphism (SNP).

RESULTS

Random-effects IVW as the primary method showed that testosterone (odds ratio (OR), 0.87; 95% confidence interval (CI), 0.41-1.82; P = 0.705), E2 (OR, 0.95; 95% CI, 0.73-1.23; P = 0.693), SHBG (OR, 1.25; 95% CI, 0.74-2.13; P = 0.400), and BT (OR, 0.99; 95% CI, 0.67-1.47; P = 0.959) had no potential causal association with SLE. The MR-Egger, weighted median, simple mode, weighted mode, and fixed-effects IVW methods all indicated consistent results. The results of the MR-Egger regression showed that there was no pleiotropy in our MR analysis (P > 0.05). The IVW Cochran's Q estimates showed that the MR analysis results of E2, SHBG, and BT on SLE had no heterogeneity (P > 0.05), but testosterone and SLE had heterogeneity (P < 0.05). The leave-one-out analysis confirmed that a single SNP did not affect the MR results.

CONCLUSIONS

Our MR analysis demonstrated that genetically predicted testosterone, E2, SHBG, and BT levels were not associated with SLE risk, but the roles of other non-genetic pathways cannot be ruled out. Key Points • This is the first MR study to explore the causal association of sex hormone-related traits with SLE. • No evidence to support causal associations between sex hormone-related traits and SLE. • Our MR analysis may provide novel insights into the causal association between sex hormone-related traits and SLE risk.

Benzo[a]pyrene Exposure Reduces Cell-Type Diversity and Stimulates Sex-Biased Damage Pathways in End Organs of Lupus-Prone Mice

Studies indicate that genetic factors only account for approximately thirty percent of all autoimmune diseases, while the rest of autoimmune pathogenesis is attributed to environmental factors including toxic chemicals. To understand if and how environmental pollutants trigger autoimmunity, we investigated the effect of benzo[a]pyrene (BaP) exposure on the development of autoimmune phenotypes in the lupus-prone MRL strain. The exposure of MRL mice to BaP over the course of 8 weeks before lupus onset resulted in total body weight loss in males, while marginal changes in anti-dsDNA levels occurred. Multi-organ analyses of BaP-treated and control MRL mice suggested that the kidney is a major organ directly affected by the metabolism of benzene-containing compounds, with increased expression of BaP-target genes including Cyp4b1 and Hao2. Intriguingly, spatial transcriptomic data showed that BaP caused a drastic reduction in cell-type diversity in both the kidneys and spleen of MRL mice. Further analysis of the molecular pathways affected suggested a sex-biased effect of BaP treatment, with the upregulated expression of angiogenesis genes in the lungs and an increased deposition of C3 in the kidneys of male mice. While SLE is more common in women, the disease is more severe in male patients, with an increased risk of disease progression to renal failure and lung cancer. Our results reveal sex-biased molecular pathways stimulated by BaP which may help explain the increased likelihood of end organ damage in males with lupus.

Sex hormones influence the intestinal microbiota composition in mice

Sex hormone secretion difference is one of the main reasons for sexually dimorphic traits in animals, which affects the dimorphism of the intestinal microbiota; however, their interaction is still unknown. Intestinal mucosa-associated microbiota (MAM) and intestinal luminal content microbiota (LM) belong to two different habitats according to the difference in interactions between bacteria and host intestinal epithelium/nutrients. To clarify the sexually dimorphic characteristics of MAM and LM and their correlation with sex hormones, 12 specific pathogen-free (SPF) Kunming mice from the same nest were fed separately according to sex. After 8 weeks, samples from the male intestinal mucosa group (MM group), the female intestinal mucosa group (FM group), the male intestinal content group (MC group), and the female intestinal content group (FC group) were collected and then, the next-generation sequencing of 16S ribosomal ribonucleic acid (rRNA) gene was performed. Our results showed that the sexual dimorphism of MAM was more obvious than that of LM and the relative abundance of Muribaculaceae, Turicibacter, and Parasutterella was significantly higher in the FM group than in the MM group (p < 0.001, p < 0.05, p < 0.05). Next, we measured the level of serum sex hormones in mice and calculated the correlation coefficient between major bacteria and sex hormones. The results showed that the correlation between MAM and sex hormones was more prominent, and finally, three bacterial genera (Muribaculaceae, Turicibacter, and Parasutterella) were obtained, which could better represent the relationship between sexual dimorphism and sex hormones. The abundance of Parasutterella is positively and negatively correlated with estradiol and testosterone (T), respectively, which may be related to the differences in the metabolism of bile acid and glucose. A decrease in the abundance of Turicibacter is closely related to autism. Our results show that the abundance of Turicibacter is negatively and positively correlated with T and estradiol, respectively, which can provide a hint for the prevalence of male autism. In conclusion, it is proposed in our study that intestinal microbiota is probably the biological basis of physiological and pathological differences due to sex, and intestinal MAM can better represent the sexual dimorphism of mice.

Innate metabolic responses against viral infections

Metabolic adaptation to viral infections critically determines the course and manifestations of disease. At the systemic level, a significant feature of viral infection and inflammation that ensues is the metabolic shift from anabolic towards catabolic metabolism. Systemic metabolic sequelae such as insulin resistance and dyslipidaemia represent long-term health consequences of many infections such as human immunodeficiency virus, hepatitis C virus and severe acute respiratory syndrome coronavirus 2. The long-held presumption that peripheral and tissue-specific 'immune responses' are the chief line of defence and thus regulate viral control is incomplete. This Review focuses on the emerging paradigm shift proposing that metabolic engagements and metabolic reconfiguration of immune and non-immune cells following virus recognition modulate the natural course of viral infections. Early metabolic footprints are likely to influence longer-term disease manifestations of infection. A greater appreciation and understanding of how local biochemical adjustments in the periphery and tissues influence immunity will ultimately lead to interventions that curtail disease progression and identify new and improved prognostic biomarkers.

X-linked genes exhibit miR6891-5p-regulated skewing in Sjögren's syndrome

Many autoimmune diseases exhibit a strikingly increased prevalence in females, with primary Sjögren's syndrome (pSS) being the most female-predominant example. However, the molecular basis underlying the female-bias in pSS remains elusive. To address this knowledge gap, we performed genome-wide, allele-specific profiling of minor salivary gland-derived mesenchymal stromal cells (MSCs) from pSS patients and control subjects, and detected major differences in the regulation of X-linked genes. In control female MSCs, X-linked genes were expressed from both paternal and maternal X chromosomes with a median paternal ratio of ~ 0.5. However, in pSS female MSCs, X-linked genes exhibited preferential expression from one of the two X chromosomes. Concomitantly, pSS MSCs showed decrease in XIST levels and reorganization of H3K27me3+ foci in the nucleus. Moreover, the HLA-locus-expressed miRNA miR6891-5p was decreased in pSS MSCs. miR6891-5p inhibition in control MSCs caused XIST dysregulation, ectopic silencing, and allelic skewing. Allelic skewing was accompanied by the mislocation of protein products encoded by the skewed genes, which was recapitulated by XIST and miR6891-5p disruption in control MSCs. Our data reveal X skewing as a molecular hallmark of pSS and highlight the importance of restoring X-chromosomal allelic balance for pSS treatment. KEY MESSAGES: X-linked genes exhibit skewing in primary Sjögren's syndrome (pSS). X skewing in pSS associates with alterations in H3K27me3 deposition. pSS MSCs show decreased levels of miR6891-5p, a HLA-expressed miRNA. miR6891-5p inhibition causes H3K27me3 dysregulation and allelic skewing.

Sexual dimorphism in COVID-19: potential clinical and public health implications

Current evidence suggests that severity and mortality of COVID-19 is higher in men than in women, whereas women might be at increased risk of COVID-19 reinfection and development of long COVID. Differences between sexes have been observed in other infectious diseases and in the response to vaccines. Sex-specific expression patterns of proteins mediating virus binding and entry, and divergent reactions of the immune and endocrine system, in particular the hypothalamic-pituitary-adrenal axis, in response to acute stress might explain the higher severity of COVID-19 in men. In this Personal View, we discuss how sex hormones, comorbidities, and the sex chromosome complement influence these mechanisms in the context of COVID-19. Due to its role in the severity and progression of SARS-CoV-2 infections, we argue that sexual dimorphism has potential implications for disease treatment, public health measures, and follow-up of patients predisposed to the development of long COVID. We suggest that sex differences could be considered in future pandemic surveillance and treatment of patients with COVID-19 to help to achieve better disease stratification and improved outcomes.

Clinical significance of anti-SSA/Ro antibody in Neuromyelitis optica spectrum disorders

BACKGROUND

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune inflammatory disease of the central nervous system (CNS), also described as CNS autoimmune astrocytopathy, due to the production of pathogenic antibodies against aquaporin-4 (AQP4) expressed on the foot of astrocytes. NMOSD coexists with autoimmune diseases and related autoantibodies [anti-Sjogren's syndrome A (anti-SSA)/Ro antibody, anti-Sjogren's syndrome B (anti-SSB)/La antibody, anti-nuclear (anti-ANA) antibodies, anti-double-stranded DNA (anti-dsDNA) antibody, anti-thyroglobulin antibody, and anti-thyroid peroxidase antibody].

OBJECTIVES

No precise conclusion has been drawn on the role of the anti-SSA/Ro antibody in NMOSD. Therefore, the aim of this work was to evaluate whether the anti-SSA/Ro antibody has an impact on the clinical manifestation or prognosis of NMOSD.

METHODS

Data were retrospectively collected from 102 patients with NMOSD diagnosed by experienced neurologists. The study population was divided into two groups based on the serum anti-SSA/Ro antibody status: NMOSD with or without anti-SSA/Ro antibody. The clinical, neuroimaging and laboratory parameters were compared between the two groups, including the neurological symptoms, MRI results, frequency of systemic autoantibodies, Expanded Disability Status Scale (EDSS), and NMOSD relapse rate. The EDSS and relapse were applied as measures of the NMOSD patient prognostic value. Cox regression analysis was used to evaluate the prognostic impact of anti-SSA/Ro antibody on NMOSD.

RESULTS

Among the 102 NMOSD patients, striking differences were observed in the positive rate of AQP4-IgG (89.2% vs. 72.3%, p = 0.046) between those patients with and without the anti-SSA/Ro antibody. In addition, NMOSD patients with anti-SSA/Ro antibody showed the presence of more frequent anti-ANA antibodies (p = 0.002), anti-SSB/La antibody (p < 0.001), anti-dsDNA antibody (p < 0.002), Sjogren's syndrome (SS, p < 0.001) and systemic lupus erythematosus (SLE, p = 0.045). Univariate and multivariate Cox regression analysis were performed to confirm that the anti-SSA/Ro antibody affected the EDSS score and the relapse of NMOSD patients. The analysis of the survival curve revealed that the EDSS score in the NMOSD patients positive for the anti-SSA/Ro antibody reached 4.0 (p = 0.035) and relapsed (p = 0.039) earlier than in the negative group.

CONCLUSION

The anti-SSA/Ro antibody could be associated with disease activity and severe disability in NMOSD.