Prior Repeated Stress Attenuates Cold-Induced Immunomodulation Associated with Browning in Mesenteric Fat of Rats

Continuous exposure to cold leads to activation of adaptive thermogenesis in brown adipose tissue but also to induction of brown/beige cell phenotype in white adipose tissue. The aim of this work was to investigate whether prior exposure to immobilization (IMO) stress may affect immune response associated with adipocyte browning in mesenteric adipose tissue (mWAT). In the first experiment, Sprague-Dawley rats were exposed to acute (3 h) or prolonged (7 days) cold exposure (4 +/- 1 degrees C). 7-day cold stimulated gene expression of uncoupling protein 1 and other browning -associated factors. In the second experiment, rats were immobilized for 7 days (2 h daily) followed by exposure to continuous cold for 1 or 7 days. Prior IMO exaggerated cold-induced sympathetic response manifested by elevated tyrosine hydroxylase (TH) protein and norepinephrine in mWAT. Induction of non-sympathetic catecholamine production demonstrated by elevated TH and PNMT (phenylethanolamine N-methyltransferase) mRNAs was observed after 7-day cold; however, prior IMO attenuated this response. 7-day cold-induced gene expression of anti-inflammatory mediators (IL-4, IL-13, IL-10, adiponectin), markers of M2 macrophages (Arg1, Retnlalpha), and eosinophil-associated molecules (eotaxin, IL-5), while inhibited expression of pro-inflammatory cytokines (IFNgamma, IL-1b, IL-6, IL-17) and monocytes (MCP-1, Ly6C). This immune response was accompanied by elevated expression of uncoupling protein-1 and other thermogenic factors. Rats exposed to prior IMO exhibited inhibition of cold-induced immune and browning -related expression pattern. Overall, we demonstrated that 7-day cold-induced browning -associated changes in rat mWAT, while prior history of repeated stress prevented this response

Exposure to a single immobilization or lipopolysaccharide challenge increases expression of genes implicated in the development of Alzheimer’s disease in the mice brain cortex

Objectives. Despite extensive research efforts, mechanisms participating on development of Alzheimer’s disease (AD) are covered only partially. Data from the last decades indicate that various stressors, as etiological factors, may play a role of in the AD. Therefore, we investigated the effect of two acute stressors, immobilization (IMO) and lipopolysaccharide (LPS), on the AD-related neuropathology

Repeated Stress Exaggerates Lipopolysaccharide-Induced Inflammatory Response in the Rat Spleen

Spleen is an immune organ innervated with sympathetic nerves which together with adrenomedullary system control splenic immune functions. However, the mechanism by which prior stress exposure modulates the immune response induced by immunogenic challenge is not sufficiently clarified. Thus, the aim of this study was to investigate the effect of a single (2 h) and repeated (2 h daily for 7 days) immobilization stress (IMO) on the innate immune response in the spleen induced by lipopolysaccharide (LPS, 100 microg/kg). LPS elevated splenic levels of norepinephrine and epinephrine, while prior IMO prevented this response. LPS did not alter de novo production of catecholamines, however, prior IMO attenuated phenylethanolamine N-methyltransferase gene expression. Particularly repeated IMO exacerbated LPS-induced down-regulation of alpha1B- and beta1-adrenergic receptors (ARs), while enhanced alpha2A- and beta2-AR mRNAs. Elevated expression of inflammatory mediators (iNOS2, IL-1beta, IL-6, TNF-alpha, IL-10) was observed following LPS and repeated IMO again potentiated this effect. These changes were associated with enhanced Ly6C gene expression, a monocyte marker, and elevated MCP-1, GM-CSF, and CXCL1 mRNAs suggesting an increased recruitment of monocytes and neutrophils into the spleen. Additionally, we observed increased Bax/Bcl-1 mRNA ratio together with reduced B cell numbers in rats exposed to repeated IMO and treated with LPS but not in acutely stressed rats. Altogether, these data indicate that repeated stress via changes in CA levels and specific alpha- and beta-AR subtypes exaggerates the inflammatory response likely by recruiting peripheral monocytes and neutrophils to the spleen, resulting in the induction of apoptosis within this tissue, particularly in B cells. These changes may alter the splenic immune functions with potentially pathological consequences

Adipocytes as a new source of catecholamine production

AbstractCatecholamines are an important regulator of lipolysis in adipose tissue. Here we show that rat adipocytes, isolated from mesenteric adipose tissue, express genes of catecholamine biosynthetic enzymes and produce catecholamines de novo. Administration of tyrosine hydroxylase inhibitor, alpha-methyl-p-tyrosine, in vitro significantly reduced concentration of catecholamines in isolated adipocytes. We hypothesize that the sympathetic innervation of adipose tissues is not the only source of catecholamines, since adipocytes also have the capacity to produce both norepinephrine and epinephrine

Sperm protamine-status correlates to the fertility of breeding bulls

During fertilization, spermatozoa make essential contributions to embryo development by providing oocyte activating factors, centrosomal components, and paternal chromosomes. Protamines are essential for proper packaging of sperm DNA; however, in contrast to the studies of oocyte-related female infertility, the influence of sperm chromatin structure on male infertility has not been evaluated extensively. The objective of this study was to determine the sperm chromatin content of bull spermatozoa by evaluating DNA fragmentation, chromatin maturity/protamination, PRM1 protein status, and nuclear shape in spermatozoa from bulls with different fertility. Relationships between protamine 1 (PRM1) and the chromatin integrity were ascertained in spermatozoa from Holstein bulls with varied (high vs. low) but acceptable fertility. Sperm DNA fragmentation and chromatin maturity (protamination) were tested using Halomax assay and toluidine blue staining, respectively. The PRM1 content was assayed using Western blotting and in-gel densitometry, flow cytometry, and immunocytochemistry. Fragmentation of DNA was increased and chromatin maturity significantly reduced in spermatozoa from low-fertility bulls compared to those from high-fertility bulls. Field fertility scores of the bulls were negatively correlated with the percentage of spermatozoa displaying reduced protamination and fragmented DNA using toluidine blue and Halomax, respectively. Bull fertility was also positively correlated with PRM1 content by Western blotting and flow cytometry. However, detection of PRM1 content by Western blotting alone was not predictive of bull fertility. In immunocytochemistry, abnormal spermatozoa showed either a lack of PRM1 or scattered localization in the apical/acrosomal region of the nuclei. The nuclear shape was distorted in spermatozoa from low-fertility bulls. In conclusion, we showed that inadequate amount and localization of PRM1 were associated with defects in sperm chromatin structure, coinciding with reduced fertility in bulls. These findings are highly significant because they reveal molecular and morphological phenotypes of mammalian spermatozoa that influence fertility

Sperm proteins ODF2 and PAWP as markers of fertility in breeding bulls

Low fertility is the single most important factor limiting livestock reproductive performance, adversely affecting the cattle industry and causing millions of dollars of economic loss. In the livestock industry, male fertility is of crucial importance for the reproductive performance of livestock. However, there is a lack of reliable biomarkers to predict bull fertility in artificial insemination service. The objective of this study was to identify sperm proteins as biomarkers for bull fertility. To discover candidate sperm quality biomarkers, sperm proteome profiling was conducted in extreme high- and extreme low-fertile bulls selected from a pool of 1000 AI sires with varied fertility. Thirty-two differentially expressed proteins were identified. Among them, high levels of sperm outer dense fiber of sperm tails 2 (ODF2) and post-acrosomal assembly of sperm head protein (PAWP/WBP2NL) represented the most extreme differences in quantity between high- and low-fertility bulls. Protein immunodetection and flow cytometry used to validate these putative fertility markers in a combined cohort of 154 AI sires. Both ODF2 and PAWP correlated significantly with fertility. In conclusion, ODF2 and PAWP can be used to assess semen quality and predict sire fertility

Repeated Stress Exaggerates Lipopolysaccharide-Induced Inflammatory Response in the Rat Spleen

Spleen is an immune organ innervated with sympathetic nerves which together with adrenomedullary system control splenic immune functions. However, the mechanism by which prior stress exposure modulates the immune response induced by immunogenic challenge is not sufficiently clarified. Thus, the aim of this study was to investigate the effect of a single (2 h) and repeated (2 h daily for 7 days) immobilization stress (IMO) on the innate immune response in the spleen induced by lipopolysaccharide (LPS, 100 microg/kg). LPS elevated splenic levels of norepinephrine and epinephrine, while prior IMO prevented this response. LPS did not alter de novo production of catecholamines, however, prior IMO attenuated phenylethanolamine N-methyltransferase gene expression. Particularly repeated IMO exacerbated LPS-induced down-regulation of alpha1B- and beta1-adrenergic receptors (ARs), while enhanced alpha2A- and beta2-AR mRNAs. Elevated expression of inflammatory mediators (iNOS2, IL-1beta, IL-6, TNF-alpha, IL-10) was observed following LPS and repeated IMO again potentiated this effect. These changes were associated with enhanced Ly6C gene expression, a monocyte marker, and elevated MCP-1, GM-CSF, and CXCL1 mRNAs suggesting an increased recruitment of monocytes and neutrophils into the spleen. Additionally, we observed increased Bax/Bcl-1 mRNA ratio together with reduced B cell numbers in rats exposed to repeated IMO and treated with LPS but not in acutely stressed rats. Altogether, these data indicate that repeated stress via changes in CA levels and specific alpha- and beta-AR subtypes exaggerates the inflammatory response likely by recruiting peripheral monocytes and neutrophils to the spleen, resulting in the induction of apoptosis within this tissue, particularly in B cells. These changes may alter the splenic immune functions with potentially pathological consequences