Sex differences in mitochondrial numbers and function are present in large cerebral arteries, but it is unclear whether these differences extend to the microcirculation. We performed an assessment of mitochondria-related proteins in cerebral microvessels (MVs) isolated from young, male and female, Sprague-Dawley rats. MVs composed of arterioles, capillaries, and venules were isolated from the cerebrum and used to perform a 3 versus 3 quantitative, multiplexed proteomics experiment utilizing tandem mass tags (TMT), coupled with liquid chromatography/mass spectrometry (LC/MS). MS data and bioinformatic analyses were performed using Proteome Discoverer version 2.2 and Ingenuity Pathway Analysis. We identified a total of 1969 proteins, of which 1871 were quantified by TMT labels. Sixty-four proteins were expressed significantly ( p < 0.05) higher in female samples compared with male samples. Females expressed more mitochondrial proteins involved in energy production, mitochondrial membrane structure, anti-oxidant enzyme proteins, and those involved in fatty acid oxidation. Conversely, males had higher expression levels of mitochondria-destructive proteins. Our findings reveal, for the first time, the full extent of sexual dimorphism in the mitochondrial metabolic protein profiles of MVs, which may contribute to sex-dependent cerebrovascular and neurological pathologies.

The 2019-2020 SARS-related coronavirus-2 (SARS-CoV-2) pandemic has brought unprecedented challenges to healthcare sectors around the world. As of November 2020, there have been over 64 million confirmed cases and approaching 2 million deaths globally. Despite the large number of positive cases, there are very limited established standards of care and therapeutic options available. To date, there is still no Food and Drug Administration (FDA) approved vaccine for COVID-19, although there are several options in various clinical trial stages. Herein, we have performed a global review evaluating the roles of age and sex on COVID-19 hospitalizations, ICU admissions, deaths in hospitals, and deaths in nursing homes. We have identified a trend in which elderly and male patients are significantly affected by adverse outcomes. There is evidence suggesting that sex hormone levels can influence immune system function against SARS-CoV-2 infection, thus reducing the adverse effects of COVID-19. Since older adults have lower levels of these sex hormones, we therefore speculate, within rational scientific context, that sex steroids, such as estrogen and progesterone, needs further consideration for use as alternative therapeutic option for treating COVID-19 elderly patients. To our knowledge, this is the first comprehensive article evaluating the significance of sex hormones in COVID-19 outcomes in older adults.

Purpose Stress can lead to short- or long-term changes in phenotype. Accumulating evidence also supports the transmission of maladaptive phenotypes, induced by adverse stressors, through the germline to manifest in subsequent generations, providing a novel mechanistic basis for the heritability of disease. In the present study in mice, we tested the hypothesis that repeated presentations of a nonharmful conditioning stress, demonstrated previously to protect against retinal ischemia, will also provide ischemic protection in the retinae of their untreated, first-generation (F1) adult offspring. Methods Swiss–Webster ND4 outbred mice were mated following a 16-week period of brief, every-other-day conditioning exposures to mild systemic hypoxia (repetitive hypoxic conditioning, RHC). Retinae of their 5-month-old F1 progeny were subjected to unilateral ischemia. Scotopic electroretinography quantified postischemic outcomes. The injury-resilient retinal proteome was revealed by quantitative mass spectrometry, and bioinformatic analyses identified the biochemical pathways and networks in which these differentially expressed proteins operate. Results Significant resilience to injury in both sexes was documented in F1 mice derived from RHC-treated parents, relative to matched F1 adult progeny derived from normoxic control parents. Ischemia-induced increases and decreases in the expression of many visual transduction proteins that are integral to photoreceptor function were abrogated by parental RHC, providing a molecular basis for the observed functional protection. Conclusions Our proteomic analyses provided mechanistic insights into the molecular manifestation of the inherited, injury-resilient phenotype. To our knowledge, this is the first study in a mammalian model documenting the reprogramming of heritability to promote disease resilience in the next generation.

Recent evidence from our laboratory documents functional resilience to retinal ischemic injury in untreated mice derived from parents exposed to repetitive hypoxic conditioning (RHC) before breeding. To begin to understand the epigenetic basis of this intergenerational protection, we used methylated DNA immunoprecipitation and sequencing to identify genes with differentially methylated promoters (DMGPs) in the prefrontal cortex of mice treated directly with the same RHC stimulus (F0-RHC) and in the prefrontal cortex of their untreated F1-generation offspring (F1-*RHC). Subsequent bioinformatic analyses provided key mechanistic insights into how changes in gene expression secondary to promoter hypo- and hypermethylation might afford such protection within and across generations. We found extensive changes in DNA methylation in both generations consistent with the expression of many survival-promoting genes, with twice the number of DMGPs in the cortex of F1*RHC mice relative to their F0 parents that were directly exposed to RHC. In contrast to our hypothesis that similar epigenetic modifications would be realized in the cortices of both F0-RHC and F1-*RHC mice, we instead found relatively few DMGPs common to both generations; in fact, each generation manifested expected injury resilience via distinctly unique gene expression profiles. Whereas in the cortex of F0-RHC mice, predicted protein-protein interactions reflected activation of an anti-ischemic phenotype, networks activated in F1-*RHC cortex comprised networks indicative of a much broader cytoprotective phenotype. Altogether, our results suggest that the intergenerational transfer of an acquired phenotype to offspring does not necessarily require the faithful recapitulation of the conditioning-modified DNA methylome of the parent.

Environmental stimuli can promote short-or long-lasting changes in phenotype through epigenetics. Under certain circumstances, induced phenotypes can be passed through the germline to subsequent generations, providing a novel mechanistic basis for disease heritability. In the present study, we tested the hypothesis that repetitively exposing parents to a nonharmful epigenetic stimulus can promote disease resilience in offspring. Male and female mice were mated following brief exposures to mild systemic hypoxia every other day for 16 weeks. Electroretinographic determinations of postischemic function in response to transient unilateral retinal ischemia in their 5month-old F1 progeny revealed significant resilience to injury relative to animals derived from normoxic control parents. Mass spectrometry identified hundreds of differentially expressed proteins between protected and injured retinae; bioinformatic analyses of the pathways and networks these proteins comprise provided specific mechanistic insights into the molecular manifestation of this injury-resilient phenotype. Thus, epigenetics can modify heritability to promote disease resilience.

Metabolic remodeling plays an important role in the pathophysiology of heart failure (HF). We sought to characterize metabolic remodeling and implicated signaling pathways in two rat models of early systolic dysfunction (MOD), and overt systolic HF (SHF). Tandem mass tag-labeled shotgun proteomics, phospho-(p)-proteomics, and non-targeted metabolomics analyses were performed in left ventricular myocardium tissue from Sham, MOD, and SHF using liquid chromatography–mass spectrometry, n = 3 biological samples per group. Mitochondrial proteins were predominantly down-regulated in MOD (125) and SHF (328) vs. Sham. Of these, 82% (103/125) and 66% (218/328) were involved in metabolism and respiration. Oxidative phosphorylation, mitochondrial fatty acid β-oxidation, Krebs cycle, branched-chain amino acids, and amino acid (glutamine and tryptophan) degradation were highly enriched metabolic pathways that decreased in SHF > MOD. Glycogen and glucose degradation increased predominantly in MOD, whereas glycolysis and pyruvate metabolism decreased predominantly in SHF. PKA signaling at the endoplasmic reticulum–mt interface was attenuated in MOD, whereas overall PKA and AMPK cellular signaling were attenuated in SHF vs. Sham. In conclusion, metabolic remodeling plays an important role in myocardial remodeling. PKA and AMPK signaling crosstalk governs metabolic remodeling in progression to SHF.

Background Mitochondrial responses to experimental strokes differ in large cerebral arteries of male and female rats. However, it is unclear whether sex‐dependent differences extend to the cerebral microcirculation. Therefore, it is important to study the cerebral microcirculation since recent evidence suggests this vascular segment is a major participant in the development of neurological diseases such as cognitive impairment, vascular dementia, and Alzheimer’s disease. We performed an unbiased quantitative discovery‐based proteomic experiment to help elucidate the sex‐dependent differential expression of mitochondria‐related proteins in cerebral microvessels (MVs) for the first time. Methods MVs were isolated from young, age‐matched, male and female, Sprague‐Dawley rats. The population and the quality of the isolated MVs (< 70 μm diameter) were confirmed by light microscopy. MVs were then used for a 3 vs. 3 quantitative multiplexed experiment utilizing tandem mass tags coupled with liquid chromatography‐mass spectrometry (LC‐MS). MS data and bioinformatic analyses were performed using Proteome Discoverer version 2.2. and Ingenuity Pathway Analysis (IPA), respectfully. Results The LC‐MS proteomic analysis identified 42 mitochondria‐related proteins with significant (p < 0.05) male and female differences. Twenty‐four proteins were more abundant in MVs of females and 18 were more prevalent in male MVs. In general, males displayed more mitochondria destructive proteins, e.g., microtubule‐associated proteins 1A/1B light chain 3B and mitochondria‐eating protein. Overexpression of neuronal pentraxin‐1 in male MVs may influence the translocation of proapoptotic proteins to mitochondria. Increased expression of monocarboxylate transporter 1 and its chaperone protein, basigin (CD147), in male MVs reflects inhibited glycolysis, impaired oxidative phosphorylation, and reduced mitochondrial anaplerotic reactions. On the other hand, females showed more inner and outer membrane proteins (several ATP synthase subunits), anti‐ROS (peroxiredoxin‐2), and proteins involved in use of alternative fuels via fatty acid beta‐oxidation (indicated by the induction of 2,4‐dienoyl‐CoA reductase, and Δ3.5‐Δ2,4‐dienoyl‐CoA isomerase). Bioinformatic analysis showed the top 5 canonical pathways that exhibit sex‐based differences are mitochondrial dysfunction, oxidative phosphorylation, sirtuin signaling, TCA cycle, and eIF2 signaling. Conclusion Female rat MVs have more anti‐inflammatory/pro‐healing proteins associated with mitochondrial activity than the male MVs. Female MV mitochondria are also more stable and versatile than male MV mitochondria. Finally, our findings reveal significant sexual dimorphism in MV mitochondrial metabolic protein profiles, all of which may contribute to the phenotypic basis for many sex‐dependent cerebrovascular pathologies Support or Funding Information HL‐093554, AHA17SDG33410366, NS094834, U54GM 104940.

Sex differences in mitochondrial numbers and function are present in large cerebral arteries, but it is unclear whether these differences extend to the microcirculation. We performed an assessment of mitochondria-related proteins in cerebral microvessels (MVs) isolated from young, male and female, Sprague-Dawley rats. MVs composed of arterioles, capillaries, and venules were isolated from the cerebrum and used to perform a 3 vs. 3 quantitative, multiplexed proteomics experiment utilizing tandem mass tags (TMT), coupled with liquid chromatography/mass spectrometry (LC/MS). MS data and bioinformatic analyses were performed using Proteome Discoverer version 2.2 and Ingenuity Pathway Analysis. We identified a total of 1,969 proteins, of which 1,871 were quantified by TMT labels. Sixty-four proteins were expressed significantly (p < 0.05) higher in female samples compared with male samples. Females expressed more mitochondrial proteins involved in energy production, mitochondrial membrane structure, anti-oxidant enzyme proteins, and those involved in fatty acid oxidation. Conversely, males had higher expression levels of mitochondria-destructive proteins. We validated our key Proteomics results with western blotting. Our findings reveal, for the first time, the full extent of sexual dimorphism in the mitochondrial metabolic protein profiles of MVs, which may contribute to sex-dependent cerebrovascular and neurological pathologies. SynopsisEnergy-producing proteins in the cerebral microvessels (MVs) of male and female rats were examined by quantitative discovery-based proteomics to gain insight into the sex-dependent etiology of cardiovascular and neurological diseases. Females expressed more mitochondrial proteins involved in energy production, membrane structure, anti-oxidant activity, and fatty acid oxidation. In contrast, males exhibited more mitochondria-destructive proteins such as mitochondrial eating protein. Our findings reveal for the first time the sexual dimorphism of mitochondria-related proteins in cerebral MVs, which may explain functional sex-related differences in MVs during health and in the etiology of neurological pathologies of cerebrovascular origin. ACKNOWLEDGMENTSWe thank Nancy Busija, MA, for editing the manuscript. We thank Dana Liu for technical help.