Sex-specific Changes Research Articles

Exploring the sex dimorphism in the expression of intestinal barrier and immune-related genes and intestinal microbiota in cage-cultured large yellow croaker (Larimichthys crocea) during the overwintering period along the Zhoushan coast

In Zhejiang province, large yellow croakers are primarily cultured in net cages, facing significant challenges during the overwintering period such as susceptibility to cold and starvation stress. Notably, the observable sexual dimorphism in the large yellow croaker hints at the likelihood of gender differences in their responses to these environmental stresses. However, the potential sex-specific adaptive changes during overwintering remain unexplored. To gain deeper insights, we investigated the expression of intestinal barrier-related genes, immune responses, and changes in intestinal microbiota during the overwintering period in males and females separately. The results revealed a more pronounced loss of body weight in females than that in males. In male intestines, there was a significant decrease in the expression of intestinal barrier-related genes (arp2/3, occludin, and zo1), contrasting with a significant increase in females. The expression of TLR1, TLR3, TLR7, TLR9, MyD88, and NF-κB genes in the intestines of female fish decreased significantly in March compared to November, while the opposite trend was observed in male fish. However, in the liver, TLR1, TLR3, TLR7, TLR9, MyD88, and NF-κB genes expression were both decreased significantly in males and females. In the male intestines, there was a significant increase in the expression of inflammatory cytokine genes (IL-1β and IL-6). In the females, IL-1β gene expression significantly decreased, while IL-6 expression increased significantly. The expression of IL-10 genes decreased in both males and females. In the liver, both the males and females exhibited a significant increase in the expression of IL-1β and IL-6 genes. Further analysis revealed greater susceptibility of male intestinal microbiota diversity during the overwintering period. Firmicutes’ relative abundance exhibited opposing changes between the males and females, and Proteobacteria abundance, driven by a significant increase in Vibrio bacteria, significantly increased in the males. In conclusion, the overwintering period may compromise the structural integrity of male fish intestines, reducing their immune function. Additionally, the response strategy of the intestinal microbiota differs between sexes. The findings provide crucial insights for crafting effective strategies and management decisions in cage-cultured large yellow croaker during the overwintering period, as well as offering theoretical references for monosex aquaculture.

Maternal exposure to tributyltin alters the breast milk, hormonal profile, and thyroid morphology of dams and induces sex-specific changes in neonate rat offspring.

Tributyltin (TBT) is the chemical substance commonly used worldwide to prevent biofouling of vessels. Due to its ability to bioaccumulate and biomagnify, even after being banned, significant concentrations of TBT can be detected in sediment, affecting marine and human life. Although studies have shown that direct exposure to TBT alters physiological parameters in mammals, the relationship between exposure to TBT during pregnancy and lactation, considered critical windows for metabolic programming, has not been fully elucidated. Our hypothesis is that offspring whose mothers were exposed to TBT during critical stages of development may exhibit dysfunctions in endocrine-metabolic parameters. We used pregnant Wistar rats that were divided into groups and received the following treatments from gestational day 7 until the end of lactation by intragastric gavage: vehicle (ethanol 0.01%; Control), low TBT dose (100 ng/kg of body weight (bw)/day; TBT100ng) and high TBT dose (1000 ng/kg bw/day; TBT1000ng). Dams and offspring at birth and weaning (21 days old) were studied. Maternal exposure to TBT promoted dose-dependent changes in dams. The findings for adiposity, milk composition and lipid profile were more pronounced in TBT100ng dams; however, thyroid morphology was altered in TBT1000ng dams. Female offspring were differentially affected by the dose of exposure. At birth, females in the TBT100ng group had low body weight, lower naso-anal length (NAL), and higher plasma T4, and at weaning, females in the TBT100ng group had lower insulin and leptin levels. Females in the TBT1000ng group had lower NAL at birth and lower leptinemia and weight of white adipose tissue at weaning. Male offspring from TBT groups showed high T3 at birth, without biometric alterations at birth or weaning. Despite these findings, both sexes exhibited dose-dependent morphological changes in the thyroid gland. Thus, maternal exposure to TBT constitutes an important route of contamination for both dams and offspring.

Lipidome characterisation and sex-specific differences in type 1 and type 2 diabetes mellitus

BackgroundIn this study, we evaluated the lipidome alterations caused by type 1 diabetes (T1D) and type 2 diabetes (T2D), by determining lipids significantly associated with diabetes overall and in both sexes, and lipids associated with the glycaemic state.MethodsAn untargeted lipidomic analysis was performed to measure the lipid profiles of 360 subjects (91 T1D, 91 T2D, 74 with prediabetes and 104 controls (CT)) without cardiovascular and/or chronic kidney disease. Ultra-high performance liquid chromatography-electrospray ionization mass spectrometry (UHPLC-ESI-MS) was conducted in two ion modes (positive and negative). We used multiple linear regression models to (1) assess the association between each lipid feature and each condition, (2) determine sex-specific differences related to diabetes, and (3) identify lipids associated with the glycaemic state by considering the prediabetes stage. The models were adjusted by sex, age, hypertension, dyslipidaemia, body mass index, glucose, smoking, systolic blood pressure, triglycerides, HDL cholesterol, LDL cholesterol, alternate Mediterranean diet score (aMED) and estimated glomerular filtration rate (eGFR); diabetes duration and glycated haemoglobin (HbA1c) were also included in the comparison between T1D and T2D.ResultsA total of 54 unique lipid subspecies from 15 unique lipid classes were annotated. Lysophosphatidylcholines (LPC) and ceramides (Cer) showed opposite effects in subjects with T1D and subjects with T2D, LPCs being mainly up-regulated in T1D and down-regulated in T2D, and Cer being up-regulated in T2D and down-regulated in T1D. Also, Phosphatidylcholines were clearly down-regulated in subjects with T1D. Regarding sex-specific differences, ceramides and phosphatidylcholines exhibited important diabetes-associated differences due to sex. Concerning the glycaemic state, we found a gradual increase of a panel of 1-deoxyceramides from normoglycemia to prediabetes to T2D.ConclusionsOur findings revealed an extensive disruption of lipid metabolism in both T1D and T2D. Additionally, we found sex-specific lipidome changes associated with diabetes, and lipids associated with the glycaemic state that can be linked to previously described molecular mechanisms in diabetes.

Genotype- and sex-specific changes in vital parameters during isoflurane anesthesia in a mouse model of Alzheimer's disease.

The prevalence of neurodegenerative diseases is increasing as is life expectancy with Alzheimer's disease accounting for two-thirds of dementia cases globally. Whether general anesthesia and surgery worsen cognitive decline is still a matter of debate and most likely depending on the interplay of various influencing factors. In order to account for this complexity, Alzheimer's disease animal models have been developed. The Tg2576 model of Alzheimer's disease is a well-established mouse model exhibiting amyloidopathy and age-dependent sex-specific differences in Alzheimer's disease symptomology. Yet, data on anesthesia in this mouse model is scarce and a systematic comparison of vital parameters during anesthesia with wild-type animals is missing. In order to investigate the safety of general anesthesia and changes in vital parameters during general anesthesia in Tg2576 mice, we did a secondary analysis of vital parameters collected during general anesthesia in aged Tg2576 mice. After governmental approval (General Administration of the Free State of Bavaria, file number: 55.2-1-54-2532-149-11) 60 mice at 10-12 months of age were exposed to isoflurane (1.6 Vol%) for 120 min, data of 58 mice was analyzed. During general anesthesia, heart rate, respiratory rate, temperature, isoflurane concentration and fraction of inspired oxygen were monitored and collected. Data were analyzed using univariate and multivariate linear mixed regression models. During general anesthesia, heart rate decreased in a sex-specific manner. Respiratory rate decreased and body temperature increased dependent on genotype. However, the changes were limited and all vital parameters stayed within physiological limits. Isoflurane anesthesia in the Tg2576 mouse model is safe and does not seem to influence experimental results by interacting with vital parameters. The present study provides information on appropriate anesthesia in order to advance research on anesthesia and AD and could contribute to improving laboratory animal welfare.

Brain serotonin and serotonin transporter expression in male and female postnatal rat offspring in response to perturbed early life dietary exposures.

Serotonin (5-HT) is critical for neurodevelopment and the serotonin transporter (SERT) modulates serotonin levels. Perturbed prenatal and postnatal dietary exposures affect the developing offspring predisposing to neurobehavioral disorders in the adult. We hypothesized that the postnatal brain 5-HT-SERT imbalance associated with gut dysbiosis forms the contributing gut-brain axis dependent mechanism responsible for such ultimate phenotypes. Employing maternal diet restricted (IUGR, n=8) and high fat+high fructose (HFhf, n=6) dietary modifications, rodent brain serotonin was assessed temporally by ELISA and SERT by quantitative Western blot analysis. Simultaneously, colonic microbiome studies were performed. At early postnatal (P) day 2 no changes in the IUGR, but a ~24% reduction in serotonin (p = 0.00005) in the HFhf group occurred, particularly in the males (p = 0.000007) revealing a male versus female difference (p = 0.006). No such changes in SERT concentrations emerged. At late P21 the IUGR group reared on HFhf (IUGR/HFhf, (n = 4) diet revealed increased serotonin by ~53% in males (p = 0.0001) and 36% in females (p = 0.023). While only females demonstrated a ~40% decrease in serotonin (p = 0.010), the males only trended lower without a significant change within the HFhf group (p = 0.146). SERT on the other hand was no different in HFhf or IUGR/RC, with only the female IUGR/HFhf revealing a 28% decrease (p = 0.036). In colonic microbiome studies, serotonin-producing Bacteriodes increased with decreased Lactobacillus at P2, while the serotonin-producing Streptococcus species increased in IUGR/HFhf at P21. Sex-specific changes emerged in association with brain serotonin or SERT in the case of Alistipase, Anaeroplasma, Blautia, Doria, Lactococcus, Proteus, and Roseburia genera. We conclude that an imbalanced 5-HT-SERT axis during postnatal brain development is sex-specific and induced by maternal dietary modifications related to postnatal gut dysbiosis. We speculate that these early changes albeit transient may permanently alter critical neural maturational processes affecting circuitry formation, thereby perturbing the neuropsychiatric equipoise.

Sex-specific changes in protein expression of membrane transporters in the brain cortex of 5xFAD mouse model of Alzheimer's disease.

Membrane transporters playing an important role in the passage of drugs, metabolites and nutrients across the membranes of the brain cells have been shown to be involved in pathogenesis of Alzheimer's disease (AD). However, little is known about sex-specific changes in transporter protein expression at the brain in AD. Here, we investigated sex-specific alterations in protein expression of three ATP-binding cassette (ABC) and five solute carriers (SLC) transporters in the prefrontal cortex of a commonly used model of familial AD (FAD), 5xFAD mice. Sensitive liquid chromatography tandem mass spectrometry-based quantitative targeted absolute proteomic analysis was applied for absolute quantification of transporter protein expression. We compared the changes in transporter protein expressions in 7-month-old male and female 5xFAD mice versus sex-matched wild-type mice. The study revealed a significant sex-specific increase in protein expression of ABCC1 (p = 0.007) only in male 5xFAD mice as compared to sex-matched wild-type animals. In addition, the increased protein expression of glucose transporter 1 (p = 0.01), 4F2 cell-surface antigen heavy chain (p = 0.01) and long-chain fatty acid transport protein 1 (p = 0.02) were found only in female 5xFAD mice as compared to sex-matched wild-type animals. Finally, protein expression of alanine/serine/cysteine/threonine transporter 1 was upregulated in both male (p = 0.02) and female (p = 0.002) 5xFAD mice. The study provides important information about sex-specific changes in brain cortical transporter expression in 5xFAD mice, which will facilitate drug development of therapeutic strategies for AD targeting these transporters and drug delivery research.

Women health and microbiota: Different aspects of well-being

In this editorial, we comment on the article by Marano et al recently published in the World Journal of Gastroenterology 2023; 29 (45): 5945-5952. We focus on the role of gut microbiota (GM) in women’s health, highlighting the need to thoroughly comprehend the sex differences in microbiota. Together, the host and GM support the host’s health. The microbiota components consist of viruses, bacteria, fungi, and archaea. This complex is an essential part of the host and is involved in neurological development, metabolic control, immune system dynamics, and host dynamic homeostasis. It has been shown that differences in the GM of males and females can contribute to chronic diseases, such as gastrointestinal, metabolic, neurological, cardiovascular, and respiratory illnesses. These differences can also result in some sex-specific changes in immunity. Every day, research on GM reveals new and more expansive frontiers, offering a wealth of innovative opportunities for preventive and precision medicine.

Neonatal nociceptive stimulation results in pain sensitization, reduction of hippocampal 5-HT1A receptor, and p-CREB expression in adult female rats

Painful invasive procedures are often performed on newborns admitted to intensive care units (ICU). The acute and long-term effects caused by these stimuli can be investigated in animal models, such as newborn rats. Previous studies have shown that animals subjected to nociceptive stimuli in the neonatal period show sex-specific behavioral changes such as signs of anxiety or depression. Under the same conditions, neonatal stimuli also provoke an increase in the rate of neurogenesis and cell activation in the hippocampal dentate gyrus. So, this study aims to identify the possible roles of central monoamines, receptor expression (5-HT1A), and signaling factors (p-CREB) underlying the long-term effects of neonatal nociceptive stimulation. For this, noxious stimulation was induced by intra-plantar injection of Complete Freund´s adjuvant (CFA) on the postnatal day 1 (P1) or 8 (P8). Control animals were not stimulated. On P75 the behavioral tests were conducted (hotplate and elevated plus maze), followed by sacrifice and molecular studies. Our results showed that neonatal nociceptive stimulation alters pain sensitization specially in females, while stimulation on P1 increases pain threshold, P8-stimulated animals respond with reduced pain threshold (P < 0.001). Hippocampal expression of 5-HT1A receptor and p-CREB were reduced in P8 F group (P < 0.001) in opposition to the increased utilization rate of dopamine and serotonin in this group (P < 0.05). This study shows sex- and age-specific responses of signaling pathways within the hippocampus accompanied by altered behavioral repertoire, at long-term after neonatal painful stimulation.

Effects of vasoactive substances on biomechanics of small resistance arteries of male and female Dahl salt-sensitive rats.

Changes in vascular biomechanics leading to increase in arterial stiffness play a pivotal role in circulatory dysfunction. Our objectives were to examine sex-specific pharmacological changes related to the biomechanics and any structural modifications in small resistance arteries of Dahl salt-sensitive male and female rats. The composite Young modulus (CYM) was determined using pressure myograph recordings, and immunohistochemistry was used for the evaluation of any structural changes in the third-order mesenteric arteries (n = 6). Animals on high-salt diet developed hypertension with significant elevation in central and peripheral blood pressures and pulse wave velocity compared to those on regular diet. There were no significant differences observed in the CYM between any of the groups (i.e., males and females) in vehicle-treated time-control studies. The presence of verapamil (0.3 μM) significantly reduced CYM in hypertensive males without changes within females compared to vehicle. This effect was abolished by phenylephrine (0.3 μM). BaCl2 (100 μM), ouabain (100 μM), and L-NAME (0.3 μM) combined significantly increased CYM in vessels from in normotensive males and females but not in hypertensive males compared to vehicle. The increase in CYM was abolished in the presence of phenylephrine. Sodium nitroprusside (0.3 μM), in the presence of phenylephrine, significantly reduced CYM in male normotensive versus hypertensive, with no differences within females. Significant differences were observed in immunohistochemical assessment of biomechanical markers of arterial stiffness between males and females. Our findings suggest sex possibly due to pressure differences to be responsible for adaptive changes in biomechanics, and varied pharmacological responses in hypertensive state.

Longitudinal analysis of the skin microbiome in association with hand eczema, hand hygiene practices and moisturizer use.

The skin microbiota maintains a physical and immunological barrier to the environment. Little is known about how the microbiome changes over time or the effect of hand hygiene practices and moisturizer use. To assess sex-specific changes in skin bacteria over time, and how the microbiome is related to self-reported hand eczema, hand hygiene practices and use of moisturizers. Swab samples from the dorsal hand were collected at baseline and 6.5 years later during the COVID-19 pandemic, in 168 participants from the RHINESSA study in Bergen, Norway. The skin samples were analysed by 16S rRNA amplicon sequencing. The alpha diversity of the hand microbiome increased from baseline to follow-up, and beta diversity differed by sex at both time points. The relative abundance increased for several bacteria from baseline to follow-up, with sex-specific differences. Current hand eczema and aggravating hand eczema during the COVID-19 pandemic were associated with an increase in Staphylococcus. High hand washing frequency at home was associated with lower alpha diversity and with higher abundance of Staphylococcus, Corynebacterium, Finegoldia, and Pseudomonas and lower abundance of Propionibacterium and Pelomonas. The alpha diversity increased with increasing time passing between hand washing and sampling, whereas more frequent moisturizer use was associated with significantly lower alpha diversity, and a change in abundance for some bacteria, such as more Pseudomonas. This longitudinal study revealed an overall increase in skin microbial diversity over a 6-year period, which was unexpected since follow-up was performed during the COVID-19 pandemic when vigorous hand hygienic practices were introduced. Sex-specific differences were identified at both time points. Individuals with hand eczema seem to develop a more dysbiotic skin bacterial community over time. Hand washing and use of moisturizers, with typically gender-specific habitual patterns, may lead to change in bacterial composition.

Microbial composition, functionality, and stress resilience or susceptibility: unraveling sex-specific patterns

BackgroundFollowing exposure to traumatic stress, women are twice as likely as men to develop mood disorders. Yet, individual responses to such stress vary, with some people developing stress-induced psychopathologies while others exhibit resilience. The factors influencing sex-related disparities in affective disorders as well as variations in resilience remain unclear; however, emerging evidence suggests differences in the gut microbiota play a role. In this study, using the single prolonged stress (SPS) model of post-traumatic stress disorder, we investigated pre- and post-existing differences in microbial composition, functionality, and metabolites that affect stress susceptibility or resilience in each sex.MethodsMale and female Sprague–Dawley rats were randomly assigned to control or SPS groups. Two weeks following SPS, the animals were exposed to a battery of behavioral tests and decapitated a day later. Based on their anxiety index, they were further categorized as SPS-resilient (SPS-R) or SPS-susceptible (SPS-S). On the day of dissection, cecum, and selected brain tissues were isolated. Stool samples were collected before and after SPS, whereas urine samples were taken before and 30 min into the SPS.ResultsBefore SPS exposure, the sympathoadrenal axis exhibited alterations within male subgroups only. Expression of tight junction protein claudin-5 was lower in brain of SPS-S males, but higher in SPS-R females following SPS. Across the study, alpha diversity remained consistently lower in males compared to females. Beta diversity revealed distinct separations between male and female susceptible groups before SPS, with this separation becoming evident in the resilient groups following SPS. At the genus level, Lactobacillus, Lachnospiraceae_Incertae_Sedis, and Barnesiella exhibited sex-specific alterations, displaying opposing abundances in each sex. Additionally, sex-specific changes were observed in microbial predictive functionality and targeted functional modules both before and after SPS. Alterations in the microbial short-chain fatty acids (SCFAs), were also observed, with major and minor SCFAs being lower in SPS-susceptible males whereas branched-chain SCFAs being higher in SPS-susceptible females.ConclusionThis study highlights distinct pre- and post-trauma differences in microbial composition, functionality, and metabolites, associated with stress resilience in male and female rats. The findings underscore the importance of developing sex-specific therapeutic strategies to effectively address stress-related disorders.HighlightsSPS model induces divergent anxiety and social behavioral responses to traumatic stress in both male and female rodents.SPS-resilient females displayed less anxiety-like behavior and initiated more interactions towards a juvenile rat than SPS-resilient males.Sex-specific pre-existing and SPS-induced differences in the gut microbial composition and predictive functionality were observed in susceptible and resilient rats.SPS-resilient males displayed elevated cecal acetate levels, whereas SPS-susceptible females exhibited heightened branched-chain SCFAs.

Sex-specific modulation of early life vocalization and cognition by Fmr1 gene dosage in a mouse model of Fragile X Syndrome

BackgroundPup-dam ultrasonic vocalizations (USVs) are essential to cognitive and socio-emotional development. In autism and Fragile X Syndrome (FXS), disruptions in pup-dam USV communication hint at a possible connection between abnormal early developmental USV communication and the later emergence of communication and social deficits.MethodsHere, we gathered USVs from PND 10 FXS pups during a short period of separation from their mothers, encompassing animals of all possible genotypes and both sexes (i.e., Fmr1-/y vs. Fmr1+/y males and Fmr1+/+, +/-, and -/- females). This allowed comparing the influence of sex and gene dosage on pups’ communication capabilities. Leveraging DeepSqueak and analyzing vocal patterns, intricate vocal behaviors such as call structure, duration, frequency modulation, and temporal patterns were examined. Furthermore, homing behavior was assessed as a sensitive indicator of early cognitive development and social discrimination. This behavior relies on the use of olfactory and thermal cues to navigate and search for the maternal or nest odor in the surrounding space.ResultsThe results show that FMRP-deficient pups of both sexes display an increased inclination to vocalize when separated from their mothers, and this behavior is accompanied by significant sex-specific changes in the main features of their USVs as well as in body weight. Analysis of the vocal repertoire and syntactic usage revealed that Fmr1 gene silencing primarily alters the USVs’ qualitative composition in males. Moreover, sex-specific effects of Fmr1 silencing on locomotor activity and homing behavior were observed. FMRP deficiency in females increased activity, reduced nest-reaching time, and extended nest time. In males, it prolonged nest-reaching time and reduced nest time without affecting locomotion.ConclusionsThese findings highlight the interplay between Fmr1 gene dosage and sex in influencing communicative and cognitive skills during infancy.

Sex-specific Differences in Resting Oscillatory Dynamics in Children with Prenatal Alcohol Exposure

At rest children with prenatal alcohol exposure (PAE) exhibit impaired static and dynamic functional connectivity, along with decreased alpha oscillations. Sex-specific information regarding the impact of PAE on whole-brain resting-state gamma spectral power remains unknown. Eyes-closed and eyes-open MEG resting-state data were examined in 83 children, ages 6–13 years of age. Using a matched design, the sample consisted of 42 typically developing children (TDC) (22 males/20 females) and 41 children with PAE and/or a fetal alcohol spectrum disorders (FASD) diagnosis (21 males/20 females). Whole-brain source resting-state spectral power was examined to determine group and sex specific relationships. Within gamma, we found sex and group specific changes such that female participants with PAE/FASD had increased gamma power when compared to female TDC and male participants with PAE/FASD. These differences were detected in most source regions analyzed during both resting-states, and were observed across the age spectrum examined. Within delta, we found sex and group specific changes such that female participants with PAE/FASD had decreased delta power when compared to female TDC and male participants with PAE/FASD. The reduced delta oscillations in female participants with PAE/FASD were detected in several source regions during eyes-closed rest and were evident at younger ages. These results indicate PAE alters neural oscillations during rest in a sex-specific manner, with females with PAE/FASD showing the largest perturbations. These results further demonstrate PAE has global effects on resting-state spectral power and connectivity, creating long-term consequences by potentially disrupting the excitation/inhibition balance in the brain, interrupting normative neurodevelopment.

Sodium oligomannate alters gut microbiota, reduces cerebral amyloidosis and reactive microglia in a sex-specific manner

It has recently become well-established that there is a connection between Alzheimer’s disease pathology and gut microbiome dysbiosis. We have previously demonstrated that antibiotic-mediated gut microbiota perturbations lead to attenuation of Aβ deposition, phosphorylated tau accumulation, and disease-associated glial cell phenotypes in a sex-dependent manner. In this regard, we were intrigued by the finding that a marine-derived oligosaccharide, GV-971, was reported to alter gut microbiota and reduce Aβ amyloidosis in the 5XFAD mouse model that were treated at a point when Aβ burden was near plateau levels. Utilizing comparable methodologies, but with distinct technical and temporal features, we now report on the impact of GV-971 on gut microbiota, Aβ amyloidosis and microglial phenotypes in the APPPS1-21 model, studies performed at the University of Chicago, and independently in the 5X FAD model, studies performed at Washington University, St. Louis.Methods To comprehensively characterize the effects of GV-971 on the microbiota-microglia-amyloid axis, we conducted two separate investigations at independent institutions. There was no coordination of the experimental design or execution between the two laboratories. Indeed, the two laboratories were not aware of each other’s experiments until the studies were completed. Male and female APPPS1-21 mice were treated daily with 40, 80, or 160 mg/kg of GV-971 from 8, when Aβ burden was detectable upto 12 weeks of age when Aβ burden was near maximal levels. In parallel, and to corroborate existing published studies and further investigate sex-related differences, male and female 5XFAD mice were treated daily with 100 mg/kg of GV-971 from 7 to 9 months of age when Aβ burden was near peak levels. Subsequently, the two laboratories independently assessed amyloid-β deposition, metagenomic, and neuroinflammatory profiles. Finally, studies were initiated at the University of Chicago to evaluate the metabolites in cecal tissue from vehicle and GV-971-treated 5XFAD mice.Results These studies showed that independent of the procedural differences (dosage, timing and duration of treatment) between the two laboratories, cerebral amyloidosis was reduced primarily in male mice, independent of strain. We also observed sex-specific microbiota differences following GV-971 treatment. Interestingly, GV-971 significantly altered multiple overlapping bacterial species at both institutions. Moreover, we discovered that GV-971 significantly impacted microbiome metabolism, particularly by elevating amino acid production and influencing the tryptophan pathway. The metagenomics and metabolomics changes correspond with notable reductions in peripheral pro-inflammatory cytokine and chemokine profiles. Furthermore, GV-971 treatment dampened astrocyte and microglia activation, significantly decreasing plaque-associated reactive microglia while concurrently increasing homeostatic microglia only in male mice. Bulk RNAseq analysis unveiled sex-specific changes in cerebral cortex transcriptome profiles, but most importantly, the transcriptome changes in the GV-971-treated male group revealed the involvement of microglia and inflammatory responses.Conclusions In conclusion, these studies demonstrate the connection between the gut microbiome, neuroinflammation, and Alzheimer’s disease pathology while highlighting the potential therapeutic effect of GV-971. GV-971 targets the microbiota-microglia-amyloid axis, leading to the lowering of plaque pathology and neuroinflammatory signatures in a sex-dependent manner when given at the onset of Aβ deposition or when given after Aβ deposition is already at higher levels.

Sex differences in colonic gene expression and fecal microbiota composition in a mouse model of obesity-associated colorectal cancer

This study investigated the sex-specific correlation between obesity and colorectal cancer emphasizing a more pronounced association in males. Estrogen, chromosomal genes, and gut bacteria were assessed in C57BL6/J male, female and ovariectomized (OVX) female mice, subjected to either a low-fat diet (LFD) or high-fat diet (HFD) for 14 weeks. Induction of colon tumor involved azoxymethane (10 mg/kg) administration, followed by three cycles of dextran sulfate sodium. Male mice on HFD exhibited higher final body weight and increased colon tumors compared to females. Colonic mucin 2 expression was significantly higher in females. HFD-modulated differentially expressed genes numbered 290 for males, 64 for females, and 137 for OVX females. Only one up-regulated gene (Gfra3) overlapped between females and OVX females, while two down-regulated genes (Thrsp and Gbp11) overlapped between males and OVX females. Genes up-regulated by HFD in males were linked to cytokine-cytokine interaction, HIF-1 signaling pathway, central carbon metabolism in cancer. Sex-specific changes in gut microbial composition in response to HFD were observed. These findings suggest a male-specific vulnerability to HFD-induced colon tumor formation, implicating key genes and colonic bacteria in colon tumorigenesis.

Abstract TMP118: Aged Maternal Gut Microbiome Impairs Offspring Behavior and Exacerbates Stroke Outcome

The microbiome plays a significant role in influencing general health. A disruption of the gut biome homeostasis, dysbiosis, can be both the effect of disease or a precondition. The maternal biome has been shown to play a vital role in offspring brain and immune development by shaping the metabolic environment for the embryo. Therefore, an aged dysbiotic maternal biome may increase stroke risk factors among offspring and additionally, worsen stroke outcome. Young female C57B6 mice 3-month (M) of age had their host gut bacteria cleared via antibiotic treatment prior to recolonization via fecal microbiome transplants from 3M control, and 14M middle aged female mice. After breeding, the subsequent offspring was aged to 14 months, followed by behavioral tests, glucose tolerance, prior to a transient 60-minute middle cerebral artery occlusion (MCAO or sham surgery). The maternal biome had a significant effect on offspring biome at 2M, 6M and 9M of age, shifting the beta-diversity of females significantly (p=&lt;0.01), and males to a lesser extent (p=0.241), extending into adulthood. Additional sex specific changes were observed in adult mouse behavior with decreased motor function and increased anxiety being prevalent in male offspring at 2 months of age (p=0.0338 and 0.0261 respectively) but not in females. At 6 months of age female offspring from dysbiotic mothers exhibited significantly impaired object recognition abilities compared to control (p=&gt;0.01). Once the offspring had been subjected to a 60 min MCAO, a spontaneous recovery was observed in NDS scores in all females and in the control males, but not in males from dysbiotic mothers, suggesting that male stroke outcome is negatively affected by dysbiotic mothers. The maternal microbiome has a significant impact on offspring biome composition and health. Mice from mothers with aged microbiome exhibited sex specific early life motor function and cognitive impairment. Additionally, male offspring from dysbiotic mothers have a worsened stroke outcome.

Abstract TMP115: White Matter Loss and Neurological Deficits Due to Chronic Global Hypoperfusion Are Worsened in a Mouse Model of Cerebral Amyloid Angiopathy

Cerebral amyloid angiopathy (CAA) is a disease of small and medium-sized vessels, characterized by amyloid deposition in the brain vasculature. The incidence of CAA increases with age and pathophysiological features (i.e., amyloid) overlap with that of Alzheimer’s Disease (AD). Cerebral hypoperfusion (CH) impairs the integrity of the blood brain barrier and contributes to cerebral atrophy and white matter loss. However, the link between hypoperfusion and vascular amyloid deposition remains understudied. We induced global CH with bilateral carotid artery stenosis (BCAS) in CAA mice of both sexes. We hypothesized that chronic CH accelerates cognitive decline in CAA, increases white matter damage, and induces gliotic changes in the brain. Using a mouse model of CAA (Tg-SwDI), male and female mice (12wks-old) were randomized to either BCAS (n=15) or sham (n=11) surgery. Cognitive (Y-maze (YM), NORT, Water Maze (WM)) and motor function (Open Field (OF)) testing was performed by a blinded investigator prior to surgery (baseline) and at regular intervals until tissue harvest 6 months post-BCAS. Brains were harvested for immunohistochemical (IHC) analysis (Kluver-Barrera (KB), Iba-1, GFAP, Myelin Basic Protein (MBP)) and flow cytometry. Sex-specific changes in spatial memory (YM) and learning (NORT/WM) were present in CAA BCAS mice, with females having an earlier onset of deficits than males. Female BCAS mice displayed deficits in cognition (NORT) at 3 (p=.003), 4 (YM, p=.0007), and 5-months (p=.01) after BCAS. Male BCAS mice demonstrated cognitive deficits 5 months post-BCAS (NORT, p=.001). Both female and male BCAS mice had poorer cognition (WM, p=.001) 6 months post-BCAS. IHC demonstrated increased demyelination (MBP, p=.004) and atrophy (KB) in the anterior corpus collosum (p=.04) and significant cortical gliosis (p=.02). The hippocampus contained higher numbers of NOX2-expressing (p= .051) and lipid-rich microglia in BCAS (p=.042) versus sham mice. Neuronal loss and increases in endothelial-cell amyloid levels were also found in BCAS CAA mice, using flow cytometry. Global CH accelerates cognitive deficits in a CAA model, an effect that is accelerated in female mice and led to gliosis, white matter damage, and lipid-accumulating microglia.

Proteomic Analysis and Sex-Specific Changes in Chronically Ischemic Swine Myocardium Treated with Sodium-Glucose Cotransporter-2 Inhibitor Canagliflozin.

Although sodium-glucose cotransporter-2 (SGLT-2) inhibitors have been shown to improve cardiovascular outcomes in general, little is presently known about any sex-specific changes that may result from this therapy. We sought to investigate and quantify potential sex-specific changes seen with the SGLT-2 inhibitor canagliflozin (CAN) in a swine model of chronic myocardial ischemia. Eighteen Yorkshire swine underwent left thoracotomy with placement of an ameroid constrictor. Two weeks post-op, swine were assigned to receive either control (F=5, M=5), or CAN 300 mg daily (F=4, M=4). Following five weeks of therapy, swine underwent myocardial functional measurements and myocardial tissue was sent for proteomic analysis. Functional measurements showed increased cardiac output, stroke volume, ejection fraction, and ischemic myocardial flow at rest in CAN males compared to control males (all p<0.05). The CAN females had no change in cardiac function when compared to control. Proteomic analysis demonstrated six total up-regulated and 97 down-regulated proteins in the CAN female group compared to the female control. Pathway analysis showed decreases in proteins in the tricarboxylic acidic cycle. The CAN male group had 639 up-regulated and 172 down-regulated proteins compared to male control. Pathway analysis showed increases in pathways related to cellular metabolism and decreases in pathways relevant to the development of cardiomyopathy and to oxidative phosphorylation. Males treated with CAN had significant improvements in cardiac function that were not observed in females. Moreover, CAN treatment in males was associated with significantly more changes in protein expression than in females. The increased proteomic changes seen in the male CAN group likely contributed to the more robust changes in cardiac function seen in males treated with CAN.

Sex-specific pleiotropic changes in emotional behavior and alcohol consumption in human α-synuclein A53T transgenic mice during early adulthood.

Point mutations in the α-synuclein coding gene may lead to the development of Parkinson's disease (PD). PD is often accompanied by other psychiatric conditions, such as anxiety, depression, and drug use disorders, which typically emerge in adulthood. Some of these point mutations, such as SNCA and A30T, have been linked to behavioral effects that are not commonly associated with PD, especially regarding alcohol consumption patterns. In this study, we investigated whether the familial PD point mutation A53T is associated with changes in alcohol consumption behavior and emotional states at ages not yet characterized by α-synuclein accumulation. The affective and alcohol-drinking phenotypes remained unaltered in female PDGF-hA53T-synuclein-transgenic (A53T) mice during both early and late adulthood. Brain region-specific activation of ceramide-producing enzymes, acid sphingomyelinase (ASM), and neutral sphingomyelinase (NSM), known for their neuroprotective properties, was observed during early adulthood but not in late adulthood. In males, the A53T mutation was linked to a reduction in alcohol consumption in both early and late adulthood. However, male A53T mice displayed increased anxiety- and depression-like behaviors during both early and late adulthood. Enhanced ASM activity in the dorsal mesencephalon and ventral hippocampus may potentially contribute to these adverse behavioral effects of the mutation in males during late adulthood. In summary, the A53T gene mutation was associated with diverse changes in emotional states and alcohol consumption behavior long before the onset of PD, and these effects varied by sex. These alterations in behavior may be linked to changes in brain ceramide metabolism.

CYP46A1-mediated cholesterol turnover induces sex-specific changes in cognition and counteracts memory loss in ovariectomized mice.

The brain-specific enzyme CYP46A1 controls cholesterol turnover by converting cholesterol into 24S-hydroxycholesterol (24OH). Dysregulation of brain cholesterol turnover and reduced CYP46A1 levels are observed in Alzheimer's disease (AD). In this study, we report that CYP46A1 overexpression in aged female mice leads to enhanced estrogen signaling in the hippocampus and improved cognitive functions. In contrast, age-matched CYP46A1 overexpressing males show anxiety-like behavior, worsened memory, and elevated levels of 5α-dihydrotestosterone in the hippocampus. We report that, in neurons, 24OH contributes to these divergent effects by activating sex hormone signaling, including estrogen receptors. CYP46A1 overexpression in female mice protects from memory impairments induced by ovariectomy while having no effects in gonadectomized males. Last, we measured cerebrospinal fluid levels of 24OH in a clinical cohort of patients with AD and found that 24OH negatively correlates with neurodegeneration markers only in women. We suggest that CYP46A1 activation is a valuable pharmacological target for enhancing estrogen signaling in women at risk of developing neurodegenerative diseases.