Effect of CD14/TLR4 antagonist on GnRH/LH secretion in ewe during central inflammation induced by intracerebroventricular administration of LPS

Obesity-Related Hypogonadism in Women

Obesity-related hypogonadotropic hypogonadism is a well-characterized condition in men (termed male obesity-related secondary hypogonadism; MOSH); however, an equivalent condition has not been as clearly described in women. The prevalence of polycystic ovary syndrome (PCOS) is known to increase with obesity, but PCOS is more typically characterized by increased gonadotropin-releasing hormone (GnRH) (and by proxy luteinizing hormone; LH) pulsatility, rather than by the reduced gonadotropin levels observed in MOSH. Notably, LH levels and LH pulse amplitude are reduced with obesity, both in women with and without PCOS, suggesting that an obesity-related secondary hypogonadism may also exist in women akin to MOSH in men. Herein, we examine the evidence for the existence of a putative non-PCOS "female obesity-related secondary hypogonadism" (FOSH). We précis possible underlying mechanisms for the occurrence of hypogonadism in this context and consider how such mechanisms differ from MOSH in men, and from PCOS in women without obesity. In this review, we consider relevant etiological factors that are altered in obesity and that could impact on GnRH pulsatility to ascertain whether they could contribute to obesity-related secondary hypogonadism including: anti-Müllerian hormone, androgen, insulin, fatty acid, adiponectin, and leptin. More precise phenotyping of hypogonadism in women with obesity could provide further validation for non-PCOS FOSH and preface the ability to define/investigate such a condition.

Rumen-protected l-carnitine supplementation during mating period altered metabolic status and reproductive performance of ewes

Current study hypothesized that dietary l-carnitine (LC) inclusion during the mating period ameliorates both metabolic status and reproductive performance of ewes. Seventy Baluchi ewes (52 ± 4.2 kg of bodyweight and 18 ± 6 months old of age) were enrolled in this study. Animals were randomly allocated into two dietary treatments, control (only basal diet) or basal diet plus supplementation with a rumen-protected LC (Carneon 20 Rumin-pro; 20% LC; Kaesler Nutrition GmbH) at the rate of 10 g/head/day from 21 days before until 35 days after introducing rams to the ewes (MP). Feed intake was monitored by subtracting the ort from feed offered. Blood sample collection was conducted on Days -10, +10 and +20 relative to MP. Pregnancy was confirmed on Day 30 post-MP. Feed intake of the ewes in the LC group was higher than the control (p < 0.05). LC supplementation increased the cholesterol concentration in the ewes (p < 0.05). Blood urea concentration of animals in the LC group was significantly lower than the control (p < 0.05). The mRNA expression of toll-like receptor 4 was evidently lower in animals supplemented with LC than the control (p < 0.05). Both lambing and fecundity rates in the LC group tended to be higher compared with the control. LC supplementation showed potential to alter certain metabolites in the ewes. A tendency for higher lambing rate may partly be driven by dams efficient energy partitioning to support foetal growth and maintaining pregnancy.

Effect of Caffeine on the Inflammatory-Dependent Changes in the GnRH/LH Secretion in a Female Sheep Model

Caffeine is one of the most widely consumed psychoactive drugs in the world. It easily crosses the blood-brain barrier, and caffeine-interacting adenosine and ryanodine receptors are distributed in various areas of the brain, including the hypothalamus and pituitary. Caffeine intake may have an impact on reproductive and immune function. Therefore, in the present study performed on the ewe model, we decided to investigate the effect of peripheral administration of caffeine (30 mg/kg) on the secretory activity of the hypothalamic-pituitary unit which regulates the reproductive function in females during both a physiological state and an immune/inflammatory challenge induced by lipopolysaccharide (LPS; 400 ng/kg) injection. It was found that caffeine stimulated (p < 0.01) the biosynthesis of gonadotropin-releasing hormone (GnRH) in the hypothalamus of ewe under both physiological and inflammatory conditions. Caffeine also increased (p < 0.05) luteinizing hormone (LH) secretion in ewes in a physiological state; however, a single administration of caffeine failed to completely release the LH secretion from the inhibitory influence of inflammation. This could result from the decreased expression of GnRHR in the pituitary and it may also be associated with the changes in the concentration of neurotransmitters in the median eminence (ME) where GnRH neuron terminals are located. Caffeine and LPS increased (p < 0.05) dopamine in the ME which may explain the inhibition of GnRH release. Caffeine treatment also increased (p < 0.01) cortisol release, and this stimulatory effect was particularly evident in sheep under immunological stress. Our studies suggest that caffeine affects the secretory activity of the hypothalamic-pituitary unit, although its effect appears to be partially dependent on the animal's immune status.

A small-molecule TLR4 antagonist reduced neuroinflammation in female E4FAD mice

BACKGROUND

APOE genotype is the greatest genetic risk factor for sporadic Alzheimer's disease (AD). APOE4 increases AD risk up to 12-fold compared to APOE3, an effect that is greater in females. Evidence suggests that one-way APOE could modulate AD risk and progression through neuroinflammation. Indeed, APOE4 is associated with higher glial activation and cytokine levels in AD patients and mice. Therefore, identifying pathways that contribute to APOE4-associated neuroinflammation is an important approach for understanding and treating AD. Human and in vivo evidence suggests that TLR4, one of the key receptors involved in the innate immune system, could be involved in APOE-modulated neuroinflammation. Consistent with that idea, we previously demonstrated that the TLR4 antagonist IAXO-101 can reduce LPS- and Aβ-induced cytokine secretion in APOE4 glial cultures. Therefore, the goal of this study was to advance these findings and determine whether IAXO-101 can modulate neuroinflammation, Aβ pathology, and behavior in mice that express APOE4.

METHODS

We used mice that express five familial AD mutations and human APOE3 (E3FAD) or APOE4 (E4FAD). Female and male E4FAD mice and female E3FAD mice were treated with vehicle or IAXO-101 in two treatment paradigms: prevention from 4 to 6 months of age or reversal from 6 to 7 months of age. Learning and memory were assessed by modified Morris water maze. Aβ deposition, fibrillar amyloid deposition, astrogliosis, and microgliosis were assessed by immunohistochemistry. Soluble levels of Aβ and apoE, insoluble levels of apoE and Aβ, and IL-1β were measured by ELISA.

RESULTS

IAXO-101 treatment resulted in lower Iba-1 coverage, lower number of reactive microglia, and improved memory in female E4FAD mice in both prevention and reversal paradigms. IAXO-101-treated male E4FAD mice also had lower Iba-1 coverage and reactivity in the RVS paradigm, but there was no effect on behavior. There was also no effect of IAXO-101 treatment on neuroinflammation and behavior in female E3FAD mice.

CONCLUSION

Our data supports that TLR4 is a potential mechanistic therapeutic target for modulating neuroinflammation and cognition in APOE4 females.

Lipopolysaccharide accelerates tryptophan degradation in the ovary and the derivative kynurenine disturbs hormone biosynthesis and reproductive performance

Lipopolysaccharide (LPS), also known as endotoxin, is a component of the outer membrane of gram-negative bacteria. LPS is released into the surrounding environment during bacterial death and lysis. Due to its chemical and thermal stability, LPS can be detected anywhere and easily exposed to humans and animals. Previous studies have shown that LPS causes hormonal imbalances, ovarian failure, and infertility in mammals. However, the potential mechanisms remain unclear. In this study, we investigated the effects and mechanisms of LPS on tryptophan degradation, both in vivo and in vitro. The effects of kynurenine, a tryptophan derivative, on granulosa cell function and reproductive performance were explored. Results showed that p38, NF-κB, and JNK signaling pathways were involved in LPS-induced Ido1 expressions and kynurenine accumulation. Furthermore, the kynurenine decreased estradiol production, but increased granulosa cell proliferation. In vivo, experiments showed that kynurenine decreased estradiol and FSH production and inhibited ovulation and corpus luteum formation. Additionally, pregnancy and offspring survival rates decreased considerably after kynurenine treatment. Our findings suggest that kynurenine accumulation disrupts hormone secretion, ovulation, corpus luteal formation, and reproductive performance in mammals.

The effects of prolactin on the immune system, its relationship with the severity of COVID-19, and its potential immunomodulatory therapeutic effect

Prolactin (PRL) is an endocrine hormone secreted by the anterior pituitary gland that has a variety of physiological effects, including milk production, immune system regulation, and anti-inflammatory effects. Elevated levels of PRL have been found in several viral infections, including 2019 coronavirus disease (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV2), a viral pathogen that has recently spread worldwide. PRL production is increased in SARS-CoV2 infection. While PRL can trigger the production of proinflammatory cytokines, it also has several anti-inflammatory effects that can reduce hyperinflammation. The exact mechanism of PRL's contribution to the severity of COVID-19 is unknown. The purpose of this review is to discuss the interaction between PRL and SARS-CoV2 infection and its possible association with the severity of COVID-19.

Exploring the role of Gut Microbiota in Obesity and PCOS: Current updates and Future Prospects

Polycystic ovary syndrome (PCOS) is a common endocrine gynecological disorder, and the specific pathogenesis of PCOS has not been elucidated. Obesity is a current major public health problem, which is also vital to PCOS. It can exacerbate PCOS symptoms via insulin resistance and hyperandrogenemia. The treatment of PCOS patients depends on the prevailing symptoms. Lifestyle interventions and weight loss remain first-line treatments for women with PCOS. The gut microbiota, which is a current research hot spot, has a substantial influence on PCOS and is closely related to obesity. The present study aimed to elucidate the function of the gut microbiota in obesity and PCOS to provide new ideas for the treatment of PCOS.

The effects of alcohol on testosterone synthesis in men: a review

INTRODUCTION

Testosterone concentrations in men decline with advancing age, with low testosterone concentrations being associated with multiple morbidities, an increased risk of early mortality, and a reduced quality of life. The purpose of this study was to examine the effects of alcohol on testosterone synthesis in men by investigating its effects on each level of the hypothalamic-pituitary-gonadal axis.

AREAS COVERED

Acute consumption of a low-to-moderate amount of alcohol increases testosterone concentrations in men, while consumption of a large volume of alcohol is associated with a reduction in serum testosterone concentrations. Elevated testosterone concentrations result from the increased activity of detoxification enzymes in the liver. Conversely, the primary mechanisms of action involved in the reduction of testosterone are increased hypothalamic-pituitary-adrenal axis activity, inflammation, and oxidative stress. When alcohol is consumed in excess, particularly chronically, it negatively affects testosterone production in men.

EXPERT OPINION

Since testosterone is an important component of men's health and wellbeing, current levels of alcohol consumption in many countries of the world require urgent attention. Elucidating the relationship between alcohol consumption and testosterone may be useful in identifying strategies to attenuate the testosterone-reducing effects of excessive or chronic alcohol consumption.

Upregulation of TLR4-Dependent ATP Production Is Critical for Glaesserella parasuis LPS-Mediated Inflammation

Glaesserella parasuis (G. parasuis), an important pathogenic bacterium, cause Glässer's disease, and has resulted in tremendous economic losses to the global swine industry. G. parasuis infection causes typical acute systemic inflammation. However, the molecular details of how the host modulates the acute inflammatory response induced by G. parasuis are largely unknown. In this study, we found that G. parasuis LZ and LPS both enhanced the mortality of PAM cells, and at the same time, the level of ATP was enhanced. LPS treatment significantly increased the expressions of IL-1β, P2X7R, NLRP3, NF-κB, p-NF-κB, and GSDMD, leading to pyroptosis. Furthermore, these proteins' expression was enhanced following extracellular ATP further stimulation. When reduced the production of P2X7R, NF-κB-NLRP3-GSDMS inflammasome signaling pathway was inhibited, and the mortality of cells was reduced. MCC950 treatment repressed the formation of inflammasome and reduced mortality. Further exploration found that the knockdown of TLR4 significantly reduced ATP content and cell mortality, and inhibited the expression of p-NF-κB and NLRP3. These findings suggested upregulation of TLR4-dependent ATP production is critical for G. parasuis LPS-mediated inflammation, provided new insights into the molecular pathways underlying the inflammatory response induced by G. parasuis, and offered a fresh perspective on therapeutic strategies.

Turning the tide on sex and the microbiota in aquatic animals

Sex-based differences in animal microbiota are increasingly recognized as of biological importance. While most animal biomass is found in aquatic ecosystems and many water-dwelling species are of high economic and ecological value, biological sex is rarely included as an explanatory variable in studies of the aquatic animal microbiota. In this opinion piece, we argue for greater consideration of host sex in studying the microbiota of aquatic animals, emphasizing the many advancements that this information could provide in the life sciences, from the evolution of sex to aquaculture.

Molecular Mechanisms of Lipopolysaccharide (LPS) Induced Inflammation in an Immortalized Ovine Luteal Endothelial Cell Line (OLENDO)

Escherichia coli (E. coli) is the most common Gram-negative bacterium causing infection of the uterus or mammary gland and is one of the major causes of infertility in livestock. In those animals affected by E. coli driven LPS-mediated infections, fertility problems occur in part due to disrupted follicular and luteal functionality. However, the molecular mechanisms by which LPS induces inflammation, and specifically, the role of LPS in the disruption of capillary morphogenesis and endothelial barrier function remain unclear. Here, we hypothesized that LPS may lead to alterations in luteal angiogenesis and vascular function by inducing inflammatory reactions in endothelial cells. Accordingly, OLENDO cells were treated with LPS followed by evaluation of the expression of selected representative proinflammatory cytokines: NF-kB, IL6, IL8, TNFα, and ICAM 1. While TNFα was not affected by treatment with LPS, transcripts of NF-kB, IL6, and IL8 were affected in a dosage-dependent manner. Additionally, the activity of TLR2 and TLR4 was blocked, resulting in suppression of the LPS-induced expression of ICAM 1, NF-kB, IL6, and IL8. Inhibition of the PKA or MAPK/ERK pathways suppressed the LPS-stimulated expression of NF-kB, IL6, and IL8, whereas blocking the PKC pathway had the opposite effect. Furthermore, LPS-induced phosphorylation of Erk1 and Erk2 was inhibited when the TLR4 or MAPK/ERK pathways were blocked. Finally, LPS seems to induce inflammatory processes in OLENDO cells via TLR2 and TLR4, utilizing different signaling pathways.

The crucial role of prolactin-lactogenic hormone in Covid-19

Prolactin (PRL) is a peptide hormone secreted from anterior pituitary involved in milk production in the females and regulation of sex drive in both sexes. PRL has pro-inflammatory and anti-inflammatory functions. High PRL serum level or hyperprolactinemia is associated with different viral infections. In coronavirus disease 2019 (Covid-19), which caused by positive-sense single-strand RNA virus known as severe acute respiratory distress syndrome coronavirus type 2 (SARS-CoV-2), PRL serum level is increased. PRL in Covid-19 may exacerbate the underlying inflammatory status by induction release of pro-inflammatory cytokines. However, PRL through its anti-inflammatory effects may reduce the hyperinflammatory status in Covid-19. The underlying mechanism of increasing PRL in Covid-19 is poorly understood. Therefore, in this review we try to find the potential anti-inflammatory or pro-inflammatory role of PRL in Covid-19. As well, this review was aimed to discuss the underlying causes and mechanisms for Covid-19-induced hyperprolactinemia.

Major Nutritional Metabolic Alterations Influencing the Reproductive System of Postpartum Dairy Cows

Early successful conception of postpartum dairy cows is crucial in determining the optimum reproductive efficiency and profitability in modern dairy farming. Due to the inherent high production potential of modern dairy cows, the extra stress burden of peri-parturient events, and associated endocrine and metabolic changes causes negative energy balance (NEBAL) in postpartum cows. The occurrence of NEBAL is associated with excessive fat mobilization in the form of non-esterified fatty acids (NEFAs). The phenomenon of NEFA mobilization furthers with occurrence of ketosis and fatty liver in postpartum dairy cows. High NEFAs and ketones are negatively associated with health and reproductive processes. An additional burden of hypocalcemia, ruminal acidosis, and high protein metabolism in postpartum cows presents further consequences for health and reproductive performance of postpartum dairy cows. This review intends to comprehend these major nutritional metabolic alterations, their mechanisms of influence on the reproduction process, and relevant mitigation strategies.

MicroRNA: Could It Play a Role in Bovine Endometritis?

Endometritis in dairy cows is a major economic problem worldwide; without advances in lifestyle management and drug treatment, it causes high morbidity and death. Micro ribonucleic acid (miRNAs) these days is seen as an important part of gene control networks. It is a class of small nucleotides 20-25, single-stranded RNA molecules. In endometritis, the inflammatory response caused by the gram-negative bacteria Escherichia coli (E. coli) alters the expression of miRNA which can regulate the innate immune system. This manuscript reviews (1) the interaction of miRNAs with the signaling of NF-κB and dysregulation of miRNAs and NF-κB activity in endometritis and (2) the activity of miR-let-7c, miR-148a, and miR-488 in NF-κB activation and their effect on endometritis. Cows with reduced immunity are more vulnerable to transition diseases, such as endometritis. During post-partum, cows undergo stress, metabolic disorders, hormonal imbalance, negative energy balance, and changes in diet. One of the many categories of regulatory molecules, which explain its natural function and pathological impact on NF-κB dysregulation, is important to inform the complexity of the immune system and to develop treatments for endometritis. It shows that miRNAs could have multiple applications in veterinary medicine. Nevertheless, a comprehensive study of is essential which should be aimed at exploring the role of microRNA at physiological level and its effect due to dysfunction and dysregulation.

Residual endotoxin induces primary graft dysfunction through ischemia/reperfusion-primed alveolar macrophages

Despite the widespread use of antibiotics, bacterial pneumonias in donors strongly predispose to the fatal syndrome of primary graft dysfunction (PGD) following lung transplantation. We report that bacterial endotoxin persists in human donor lungs after pathogen is cleared with antibiotics and is associated with neutrophil infiltration and PGD. In mouse models, depletion of tissue-resident alveolar macrophages (TRAMs) attenuated neutrophil recruitment in response to endotoxin as shown by compartmental staining and intravital imaging. Bone marrow chimeric mice revealed that neutrophils were recruited by TRAM through activation of TLR4 in a MyD88-dependent manner. Intriguingly, low levels of endotoxin, insufficient to cause donor lung injury, promoted TRAM-dependent production of CXCL2, increased neutrophil recruitment, and led to PGD, which was independent of donor NCMs. Reactive oxygen species (ROS) increased in human donor lungs starting from the warm-ischemia phase and were associated with increased transcription and translocation to the plasma membrane of TLR4 in donor TRAMs. Consistently, scavenging ROS or inhibiting their production to prevent TLR4 transcription/translocation or blockade of TLR4 or coreceptor CD14 on donor TRAMs prevented neutrophil recruitment in response to endotoxin and ameliorated PGD. Our studies demonstrate that residual endotoxin after successful treatment of donor bacterial pneumonia promotes PGD through ischemia/reperfusion-primed donor TRAMs.

Review: Pro-inflammatory cytokines and hypothalamic inflammation: implications for insufficient feed intake of transition dairy cows

Improvements in feed intake of dairy cows entering the early lactation period potentially decrease the risk of metabolic disorders, but before developing approaches targeting the intake level, mechanisms controlling and dysregulating energy balance and feed intake need to be understood. This review focuses on different inflammatory pathways interfering with the neuroendocrine system regulating feed intake of periparturient dairy cows. Subacute inflammation in various peripheral organs often occurs shortly before or after calving and is associated with increased pro-inflammatory cytokine levels. These cytokines are released into the circulation and sensed by neurons located in the hypothalamus, the key brain region regulating energy balance, to signal reduction in feed intake. Besides these peripheral humoral signals, glia cells in the brain may produce pro-inflammatory cytokines independent of peripheral inflammation. Preliminary results show intensive microglia activation in early lactation, suggesting their involvement in hypothalamic inflammation and the control of feed intake of dairy cows. On the other hand, pro-inflammatory cytokine-induced activation of the vagus nerve transmits signalling to the brain, but this pathway seems not exclusively necessary to signal feed intake reduction. Yet, less studied in dairy cows so far, the endocannabinoid system links inflammation and the hypothalamic control of feed intake. Distinct endocannabinoids exert anti-inflammatory action but also stimulate the posttranslational cleavage of neuronal proopiomelanocortin towards β-endorphin, an orexigen promoting feed intake. Plasma endocannabinoid concentrations and hypothalamic β-endorphin levels increase from late pregnancy to early lactation, but less is known about the regulation of the hypothalamic endocannabinoid system during the periparturient period of dairy cows. Dietary fatty acids may modulate the formation of endocannabinoids, which opens new avenues to improve metabolic health and immune status of dairy cows.

Effect of Inflammation on Female Gonadotropin-Releasing Hormone (GnRH) Neurons: Mechanisms and Consequences

: Inflammation has a well-known suppressive effect on fertility. The function of gonadotropin-releasing hormone (GnRH) neurons, the central regulator of fertility is substantially altered during inflammation in females. In our review we discuss the latest results on how the function of GnRH neurons is modified by inflammation in females. We first address the various effects of inflammation on GnRH neurons and their functional consequences. Second, we survey the possible mechanisms underlying the inflammation-induced actions on GnRH neurons. The role of several factors will be discerned in transmitting inflammatory signals to the GnRH neurons: cytokines, kisspeptin, RFamide-related peptides, estradiol and the anti-inflammatory cholinergic pathway. Since aging and obesity are both characterized by reproductive decline our review also focuses on the mechanisms and pathophysiological consequences of the impact of inflammation on GnRH neurons in aging and obesity.

Effect of Central Injection of Neostigmine on the Bacterial Endotoxin Induced Suppression of GnRH/LH Secretion in Ewes during the Follicular Phase of the Estrous Cycle

Induced by a bacterial infection, an immune/inflammatory challenge is a potent negative regulator of the reproduction process in females. The reduction of the synthesis of pro-inflammatory cytokine is considered as an effective strategy in the treatment of inflammatory induced neuroendocrine disorders. Therefore, the effect of direct administration of acetylcholinesterase inhibitor—neostigmine—into the third ventricle of the brain on the gonadotropin-releasing hormone (GnRH) and luteinizing hormone (LH) secretions under basal and immune stress conditions was evaluated in this study. In the study, 24 adult, 2-years-old Blackhead ewes during the follicular phase of their estrous cycle were used. Immune stress was induced by the intravenous injection of LPS Escherichia coli in a dose of 400 ng/kg. Animals received an intracerebroventricular injection of neostigmine (1 mg/animal) 0.5 h before LPS/saline treatment. It was shown that central administration of neostigmine might prevent the inflammatory-dependent decrease of GnRH/LH secretion in ewes and it had a stimulatory effect on LH release. This central action of neostigmine is connected with its inhibitory action on local pro-inflammatory cytokines, such as interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)α synthesis in the hypothalamus, which indicates the importance of this mediator in the inhibition of GnRH secretion during acute inflammation.

Association between CD14 rs2569190 C>T polymorphism and ischemic stroke susceptibility: a meta-analysis based on 5,277 subjects

INTRODUCTION

Previous epidemiological studies have suggested that CD14 rs2569190 C>T polymorphism plays an important role in ischemic stroke (IS) risk, but the results were inconsistent. Therefore, we conducted a meta-analysis to determine the association between CD14 rs2569190 C>T polymorphism and IS susceptibility.

METHODS

Online databases were searched from inception up to July 1, 2018, for studies concerning CD14 rs2569190 C>T polymorphism and its association with IS susceptibility. ORs and corresponding 95% CIs were calculated in the genetic models of each polymorphism locus with Stata Version 14.0. Furthermore, heterogeneity, meta-regression, accumulative analyses, sensitivity analyses, and publication bias were examined.

RESULTS

Overall, 10 observed studies involving 5,277 subjects were included in this meta-analysis on CD14 rs2569190 C>T polymorphism. Generally, no significant associations were found between CD14 rs2569190 C>T polymorphism and IS risk (allele contrast of T vs C: OR =1.03, 95% CI =0.96-1.12, P=0.41, I2=27.8%; co-dominant models of CT vs CC: OR =1.01, 95% CI =0.81-1.25, P=0.95, I2=51.9%; co-dominant models of TT vs CC: OR =1.04, 95% CI =0.89-1.22, P=0.62, I2=25.1%; dominant model of CT + TT vs CC: OR =1.02, 95% CI =0.84-1.25, P=0.82, I2=51.4%; recessive model of TT vs CC + CT: OR =1.07, 95% CI =0.95-1.22, P=0.28, I2=0%), similar to the results in the subgroup analysis.

CONCLUSION

The current evidence indicated that CD14 rs2569190 C>T polymorphism was not a critical risk factor for IS development.