Decreased or impaired proliferation capability of dermal fibroblasts interferes with successful wound healing. Several growth factors tested failed to fully restore the growth of fibroblasts, possibly due to their rapid degradation by proteases. It is therefore critical to find new agents which have stimulatory effects on fibroblasts while being highly resistant to degradation. In such a scenario, the activities of two agonistic analogs of growth hormone releasing hormone (GHRH), MR-409 and MR-502, were evaluated for their impact on proliferation and survival of primary human dermal fibroblasts. In vitro, both analogs significantly stimulated cell growth by more than 50%. Under serum-depletion induced stress, fibroblasts treated with MR-409 or MR-502 demonstrated better survival rates than control. These effects can be inhibited by either PD98059 or wortmannin. Signaling through MEK/ERK1/2 and PI3K/AKT in an IGF-1 receptor-independent manner is required. In vivo, MR-409 promoted wound closure. Animals treated topically with MR-409 healed earlier than controls in a dose-dependent manner. Histologic examination revealed better wound contraction and less fibrosis in treated groups. In conclusion, MR-409 is a potent mitogenic and anti-apoptotic factor for primary human dermal fibroblasts. Its beneficial effects on wound healing make it a promising agent for future development.

Although its unclear oncological risk, which led to more than 20 years of prohibition of its use, fat grafting to the breast is widely used nowadays even for aesthetic purposes. Thus, we proposed an experimental model in rats to analyze the inflammatory activity, cellular proliferation and levels of Plasminogen Activator Inhibitor (PAI-1) in grafted fat, and in native fat exposed to high-energy diet in order to study the oncological potential of fat tissue.

In experimental obesity, the hypothalamus is affected by an inflammatory response activated by dietary saturated fats. This inflammation is triggered as early as one day after exposure to a high-fat diet, and during its progression, there is recruitment of inflammatory cells from the systemic circulation. The objective of the present study was identifying chemokines potentially involved in the development of hypothalamic diet-induced inflammation. In order to identify chemokines potentially involved in this process, we performed a real-time PCR array that determined Ackr2 as one of the transcripts undergoing differential regulation in obese-prone as compared to obese-resistant mice fed a high-fat diet for three days. ACKR2 is a decoy receptor that acts as an inhibitor of the signals generated by several CC inflammatory chemokines. Our results show that Ackr2 expression is rapidly induced after exposure to dietary fats both in obese-prone and obese-resistant mice. In immunofluorescence studies, ACKR2 was detected in hypothalamic neurons expressing POMC and NPY and also in microglia and astrocytes. The lentiviral overexpression of ACKR2 in the hypothalamus reduced diet-induced hypothalamic inflammation; however, there was no change in spontaneous caloric intake and body mass. Nevertheless, the overexpression of ACKR2 resulted in improvement of glucose tolerance, which was accompanied by reduced insulin secretion and increased whole body insulin sensitivity. Thus, ACKR2 is a decoy chemokine receptor expressed in most hypothalamic cells that is modulated by dietary intervention and acts to reduce diet-induced inflammation, leading to improved glucose tolerance due to improved insulin action.

Obesity-associated hypothalamic inflammation plays an important role in the development of defective neuronal control of whole body energy balance. Because dietary fats are the main triggers of hypothalamic inflammation, we hypothesized that CD1, a lipid-presenting protein, may be involved in the hypothalamic inflammatory response in obesity. Here, we show that early after the introduction of a high-fat diet, CD1 expressing cells gradually appear in the mediobasal hypothalamus. The inhibition of hypothalamic CD1 reduces diet-induced hypothalamic inflammation and rescues the obese and glucose-intolerance phenotype of mice fed a high-fat diet. Conversely, the chemical activation of hypothalamic CD1 further increases diet-induced obesity and hypothalamic inflammation. A bioinformatics analysis revealed that hypothalamic CD1 correlates with transcripts encoding for proteins known to be involved in diet-induced hypothalamic abnormalities in obesity. Thus, CD1 is involved in at least part of the hypothalamic inflammatory response in diet-induced obesity and its modulation affects the body mass phenotype of mice.

Uveal melanoma (UM) is the most common primary intraocular malignancy with very poor prognosis. Conventional chemotherapy only rarely prolongs the survival, therefore patients require novel treatment modalities. The discovery of specific receptors for hypothalamic hormones on cancer cells has led to the development of radiolabeled and cytotoxic hormone analogs.

Management of castration-resistant prostate cancer (CRPC) is challenging due to lack of efficacious therapy. Luteinizing hormone-releasing hormone analogs appear to act directly on cells based on the LHRH receptors on human prostate adenocarcinoma cells. We explored anticancer activity of a cytotoxic analog of LHRH, AEZS-108 consisting of LHRH agonist linked to doxorubicin. Nude mice bearing DU-145 tumors were used to compare antitumor effects of AEZS-108 with its individual constituents or their unconjugated combination. The tumor growth inhibition of conjugate was greatest among treatment groups (90.5% inhibition vs. 41% by [D-Lys(6)]LHRH+DOX). The presence of LHRH receptors on DU-145 cells was confirmed by immunocytochemistry. In vitro, AEZS-108 significantly inhibited cell proliferation (61.2% inhibition) and elevated apoptosis rates (by 46%). By the detection of the inherent doxorubicin fluorescence, unconjugated doxorubicin was seen in the nucleus; the conjugate was perinuclear and at cell membrane. Autophagy, visualized by GFP-tagged p62 reporter, was increased by AEZS-108 (7.9-fold vs. 5.3-fold by DOX+[D-Lys(6)]LHRH. AEZS-108 more effectively increased reactive oxygen species (ROS, 2-fold vs. 1.4-fold by DOX+[D-Lys(6)]LHRH) and levels of the apoptotic regulator p21 in vivo and in vitro. We demonstrate robust inhibitory effects of the targeted cytotoxic LHRH analog AEZS-108 on LHRHR positive castration-resistant prostate cancer cells.

In both human and experimental obesity, inflammatory damage to the hypothalamus plays an important role in the loss of the coordinated control of food intake and energy expenditure. Upon prolonged maintenance of increased body mass, the brain changes the defended set point of adiposity, and returning to normal weight becomes extremely difficult. Here we show that in prolonged but not in short-term obesity, the ubiquitin/proteasome system in the hypothalamus fails to maintain an adequate rate of protein recycling, leading to the accumulation of ubiquitinated proteins. This is accompanied by an increased colocalization of ubiquitin and p62 in the arcuate nucleus and reduced expression of autophagy markers in the hypothalamus. Genetic protection from obesity is accompanied by the normal regulation of the ubiquitin/proteasome system in the hypothalamus, whereas the inhibition of proteasome or p62 results in the acceleration of body mass gain in mice exposed for a short period to a high-fat diet. Thus, the defective regulation of the ubiquitin/proteasome system in the hypothalamus may be an important mechanism involved in the progression and autoperpetuation of obesity.

Extrapituitary roles for hypothalamic neurohormones have recently become apparent and clinically relevant, based on the use of synthetic peptide analogs for the treatment of multiple conditions including cancers, pulmonary edema and myocardial infarction. In the eye, it has been suggested that some of these hormones and their receptors may be present in the ciliary body, iris, trabecular meshwork and retina, but their physiological role has yet to be elucidated. Our study intends to comprehensively demonstrate the expression of some hypothalamic neuroendocrine hormones and their receptors within different retinal and extraretinal structures of the human eye. Immunofluorescence, Western blot analysis, and RT-PCR were used to evaluate the qualitative and quantitative expression of Luteinizing Hormone Releasing Hormone (LHRH), Growth Hormone Releasing Hormone (GHRH), Thyrotropin Releasing Hormone (TRH), Gastrin Releasing Peptide (GRP) and Somatostatin as well as their respective receptors (LHRH-R, GHRH-R, TRH-R, GRP-R, SST-R1) in cadaveric human eye tissue and in paraffinized human eye tissue sections. The hypothalamic hormones LHRH, GHRH, TRH, GRP and Somatostatin and their respective receptors (LHRH-R, GHRH-R, TRH-R, GRPR/BB2 and SST-R1), were expressed in the conjunctiva, cornea, trabecular meshwork, ciliary body, lens, retina, and optic nerve.

It has been shown that growth hormone-releasing hormone (GHRH) reduces cardiomyocyte (CM) apoptosis, prevents ischemia/reperfusion injury, and improves cardiac function in ischemic rat hearts. However, it is still not known whether GHRH would be beneficial for life-threatening pathological conditions, like cardiac hypertrophy and heart failure (HF). Thus, we tested the myocardial therapeutic potential of GHRH stimulation in vitro and in vivo, using GHRH or its agonistic analog MR-409. We show that in vitro, GHRH(1-44)NH2 attenuates phenylephrine-induced hypertrophy in H9c2 cardiac cells, adult rat ventricular myocytes, and human induced pluripotent stem cell-derived CMs, decreasing expression of hypertrophic genes and regulating hypertrophic pathways. Underlying mechanisms included blockade of Gq signaling and its downstream components phospholipase Cβ, protein kinase Cε, calcineurin, and phospholamban. The receptor-dependent effects of GHRH also involved activation of Gαs and cAMP/PKA, and inhibition of increase in exchange protein directly activated by cAMP1 (Epac1). In vivo, MR-409 mitigated cardiac hypertrophy in mice subjected to transverse aortic constriction and improved cardiac function. Moreover, CMs isolated from transverse aortic constriction mice treated with MR-409 showed improved contractility and reversal of sarcolemmal structure. Overall, these results identify GHRH as an antihypertrophic regulator, underlying its therapeutic potential for HF, and suggest possible beneficial use of its analogs for treatment of pathological cardiac hypertrophy.

In experimental models, hypothalamic inflammation is an early and determining factor in the installation and progression of obesity. Pharmacological and gene-based approaches have proven efficient in restraining inflammation and correcting the obese phenotypes. However, the role of nutrients in the modulation of hypothalamic inflammation is unknown.

Defective liver gluconeogenesis is the main mechanism leading to fasting hyperglycemia in type 2 diabetes, and, in concert with steatosis, it is the hallmark of hepatic insulin resistance. Experimental obesity results, at least in part, from hypothalamic inflammation, which leads to leptin resistance and defective regulation of energy homeostasis. Pharmacological or genetic disruption of hypothalamic inflammation restores leptin sensitivity and reduces adiposity. Here, we evaluate the effect of a hypothalamic anti-inflammatory approach to regulating hepatic responsiveness to insulin. Obese rodents were treated by intracerebroventricular injections, with immunoneutralizing antibodies against Toll-like receptor (TLR)4 or tumor necrosis factor (TNF)α, and insulin signal transduction, hepatic steatosis, and gluconeogenesis were evaluated. The inhibition of either TLR4 or TNFα reduced hypothalamic inflammation, which was accompanied by the reduction of hypothalamic resistance to leptin and improved insulin signal transduction in the liver. This was accompanied by reduced liver steatosis and reduced hepatic expression of markers of steatosis. Furthermore, the inhibition of hypothalamic inflammation restored defective liver glucose production. All these beneficial effects were abrogated by vagotomy. Thus, the inhibition of hypothalamic inflammation in obesity results in improved hepatic insulin signal transduction, leading to reduced steatosis and reduced gluconeogenesis. All these effects are mediated by parasympathetic signals delivered by the vagus nerve.

Antagonists of growth hormone-releasing hormone (GHRH) are being developed for the treatment of various human cancers.

Therapeutic strategies should be designed to transform aggressive prostate cancer phenotypes to a chronic situation. To evaluate the effects of the new growth hormone-releasing hormone receptor (GHRH-R) antagonists: MIA-602, MIA-606, and MIA-690 on processes associated with cancer progression as cell proliferation, adhesion, migration, and angiogenesis.

Hypothalamic adult neurogenesis provides the basis for renewal of neurons involved in the regulation of whole-body energy status. In addition to hormones, cytokines and growth factors, components of the diet, particularly fatty acids, have been shown to stimulate hypothalamic neurogenesis; however, the mechanisms behind this action are unknown. Here, we hypothesized that GPR40 (FFAR1), the receptor for medium and long chain unsaturated fatty acids, could mediate at least part of the neurogenic activity in the hypothalamus. We show that a GPR40 ligand increased hypothalamic cell proliferation and survival in adult mice. In postnatal generated neurospheres, acting in synergy with brain-derived neurotrophic factor (BDNF) and interleukin 6, GPR40 activation increased the expression of doublecortin during the early differentiation phase and of the mature neuronal marker, microtubule-associated protein 2 (MAP2), during the late differentiation phase. In Neuro-2a proliferative cell-line GPR40 activation increased BDNF expression and p38 activation. The chemical inhibition of p38 abolished GPR40 effect in inducing neurogenesis markers in neurospheres, whereas BDNF immunoneutralization inhibited GPR40-induced cell proliferation in the hypothalamus of adult mice. Thus, GPR40 acts through p38 and BDNF to induce hypothalamic neurogenesis. This study provides mechanistic advance in the understating of how a fatty acid receptor regulates adult hypothalamic neurogenesis.

Interleukin-17 (IL-17) is expressed in the intestine in response to changes in the gut microbiome landscape and plays an important role in intestinal and systemic inflammatory diseases. There is evidence that dietary factors can also modify the expression of intestinal IL-17. Here, we hypothesized that, similar to several other gut-produced factors, IL-17 may act in the hypothalamus to modulate food intake. We confirm that food intake increases IL-17 expression in the mouse ileum and human blood. There is no expression of IL-17 in the hypothalamus; however, IL-17 receptor A is expressed in both pro-opiomelanocortin (POMC) and agouti-related peptide (AgRP) neurons. Upon systemic injection, IL-17 promoted a rapid increase in hypothalamic POMC expression, which was followed by a late increase in the expression of AgRP. Both systemic and intracerebroventricular injections of IL-17 reduced calorie intake without affecting whole-body energy expenditure. Systemic but not intracerebroventricular injection of IL-17 increase brown adipose tissue temperature. Thus, IL-17 is a gut-produced factor that is controlled by diet and modulates food intake by acting in the hypothalamus. Our findings provide the first evidence of a cytokine that is acutely regulated by food intake and plays a role in the regulation of eating.

Obesity has been associated with cognitive decline, atrophy of brain regions related to learning and memory, and higher risk of developing dementia. However, the molecular mechanisms underlying these neurological alterations are still largely unknown. Here, we investigate the effects of palmitate, a saturated fatty acid present at high amounts in fat-rich diets, in the brain. Palmitate is increased in the cerebrospinal fluid (CSF) of overweight and obese patients with amnestic mild cognitive impairment. In mice, intracerebroventricular infusion of palmitate impairs synaptic plasticity and memory. Palmitate induces astroglial and microglial activation in the mouse hippocampus, and its deleterious impact is mediated by microglia-derived tumor necrosis factor alpha (TNF-α) signaling. Our results establish that obesity is associated with increases in CSF palmitate. By defining a pro-inflammatory mechanism by which abnormal levels of palmitate in the brain impair memory, the results further suggest that anti-inflammatory strategies may attenuate memory impairment in obesity.

Interleukin-6 (IL6) produced in the context of exercise acts in the hypothalamus reducing obesity-associated inflammation and restoring the control of food intake and energy expenditure. In the hippocampus, some of the beneficial actions of IL6 are attributed to its neurogenesis-inducing properties. However, in the hypothalamus, the putative neurogenic actions of IL6 have never been explored, and its potential to balance energy intake can be an approach to prevent or attenuate obesity.

The endoplasmic reticulum (ER) stress is one of the mechanisms related to decreased insulin secretion and beta cell death, contributing to the progress of type 2 diabetes mellitus (T2D). Thus, investigating agents that can influence this process would help prevent the development of T2D. Recently, the growth-hormone-releasing hormone (GHRH) action has been demonstrated in INS-1E cells, in which it increases cell proliferation and insulin secretion. As the effects of GHRH and its agonists have not been fully elucidated in the beta cell, we proposed to investigate them by evaluating the role of the GHRH agonist, MR-409, in cells under ER stress. Our results show that the agonist was unable to ameliorate or prevent ER stress. However, cells exposed to the agonist showed less oxidative stress and greater survival even under ER stress. The mechanisms by which GHRH agonist, MR-409, leads to these outcomes require further investigation.

Growth hormone-releasing hormone (GHRH) is a potent stimulator of growth hormone (GH) secretion from the pituitary gland. Although GHRH is essential for the growth of immune cells, the regulatory effects of its antagonist in granulomatous disease remain unknown.

Currently, up to 35% off all drugs approved for the treatment of human diseases belong to the G-protein-coupled receptor (GPCR) family. Out of the almost 800 existing GPCRs, 25% have no known endogenous ligands and are regarded as orphan receptors; many of these are currently under investigation as potential pharmacological targets. Here, we hypothesised that orphan GPCRs expressed in the hypothalamus could be targets for the treatment of obesity and other metabolic diseases. Using bioinformatic tools, we identified 78 class A orphan GPCRs that are expressed in the hypothalamus of mice. Initially, we selected two candidates and determined their responsivities to nutritional interventions: GPR162, the GPCR with highest expression in the hypothalamus, and GPR68, a GPCR with intermediate expression in the hypothalamus and that has never been explored for its potential involvement in metabolic regulation. GPR162 expression was not modified by fasting/feeding or by the consumption of a high-fat diet, and was therefore not subsequently evaluated. Conversely, GPR68 expression increased in response to the consumption of a high-fat diet and reduced under fasting conditions. Using immunofluorescence, GPR68 was identified in both proopiomelanocortin-expressing and agouti-related peptide-expressing neurons in the hypothalamic arcuate nucleus. Acute inhibition of GPR68 with an allosteric modulator promoted an increase in the expression of the orexigenic agouti-related peptide and neuropeptide Y, whereas 4- and 12-h inhibition of GPR68 resulted in increased caloric intake. Thus, GPR68 has emerged as an orphan GPCR that is expressed in the hypothalamus and is involved in the regulation of feeding.