27-Hydroxycholesterol acts on estrogen receptor α expressed by POMC neurons in the arcuate nucleus to modulate feeding behavior.

Oxysterols are metabolites of cholesterol that regulate cholesterol homeostasis. Among these, the most abundant oxysterol is 27-hydroxycholesterol (27HC), which can cross the blood-brain barrier. Because 27HC functions as an endogenous selective estrogen receptor modulator, we hypothesize that 27HC binds to the estrogen receptor α (ERα) in the brain to regulate energy balance. Supporting this view, we found that delivering 27HC to the brain reduced food intake and activated proopiomelanocortin (POMC) neurons in the arcuate nucleus of the hypothalamus (POMCARH) in an ERα-dependent manner. In addition, we observed that inhibiting brain ERα, deleting ERα in POMC neurons, or chemogenetic inhibition of POMCARH neurons blocked the anorexigenic effects of 27HC. Mechanistically, we further revealed that 27HC stimulates POMCARH neurons by inhibiting the small conductance of the calcium-activated potassium (SK) channel. Together, our findings suggest that 27HC, through its interaction with ERα and modulation of the SK channel, inhibits food intake as a negative feedback mechanism against a surge in circulating cholesterol.

High-intensity interval training improves hypothalamic inflammation by suppressing HIF-1α signaling in microglia of male C57BL/6J mice.

Repeated bouts of high-intensity interval training (HIIT) induce an improvement in metabolism via plasticity of melanocortin circuits and attenuated hypothalamic inflammation. HIF-1α, which plays a vital role in hypothalamus-mediated regulation of peripheral metabolism, is enhanced in the hypothalamus by HIIT. This study aimed to investigate the effects of HIIT on hypothalamic HIF-1α expression and peripheral metabolism in obese mice and the underlying molecular mechanisms. By using a high-fat diet (HFD)-induced obesity mouse model, we determined the effect of HIIT on energy balance and the expression of the hypothalamic appetite-regulating neuropeptides, POMC and NPY. Moreover, hypothalamic HIF-1α signaling and its downstream glycolytic enzymes were explored after HIIT intervention. The state of microglia and microglial NF-κB signaling in the hypothalamus were also examined in vivo. In vitro by using an adenovirus carrying shRNA-HIF1ß, we explored the impact of HIF-1 signaling on glycolysis and NF-κB inflammatory signaling in BV2 cells. Food intake was suppressed and whole-body metabolism was improved in exercised DIO mice, accompanied by changes in the expression of POMC and NPY. Moreover, total and microglial HIF-1α signaling were obviously attenuated in the hypothalamus, consistent with the decreased levels of glycolytic enzymes. Both HFD-induced microglial activation and hypothalamic NF-κB signaling were significantly suppressed following HIIT in vivo. In BV2 cells, after HIF-1 complex knockdown, glycolysis and NF-κB inflammatory signaling were significantly attenuated. The data indicate that HIIT improves peripheral metabolism probably via attenuated HFD-induced microglial activation and microglial NF-κB signaling in the hypothalamus, which could be mediated by suppressed microglial HIF-1α signaling.

Phylogeography and genetic structure of Papaver bracteatum populations in Iran based on genotyping-by-sequencing (GBS).

Papaver bracteatum, known for its high thebaine content and absence of morphine, has emerged as a promising alternative to opium poppy for codeine production. In this study, our objective was to create a diverse panel representing the natural variation of this species in Iran. To achieve this, we employed genotyping-by-sequencing to obtain genome-wide distributed single-nucleotide polymorphisms (SNPs) for phylogeographic analysis, population structure assessment, and evaluation of genetic diversity within P. bracteatum populations. A total of 244 P. bracteatum individuals from 13 distinct populations formed seven genetic groups, along with one highly admixed population. We observed a clear split between the populations inhabiting the Alborz Mts. in the east and Zagros Mts. in the west. In between these mountain ranges, the population of Kachal Mangan exhibited a high degree of genetic admixture between both genetic groups. At or after the end of the last glacial maximum, when climate conditions rapidly changed, all P. bracteatum populations experienced a strong demographic bottleneck reducing the already small effective population sizes further before they increased to their recent strengths. Our results suggest that the ongoing climate change together with human pressure on the species' habitats and limited seed-dispersal ability are potential factors contributing today to rising genetic isolation of P. bracteatum populations. Our results provide genetic data that can be used for conservation measures to safeguard the species' genetic diversity as a resource for future breeding approaches in this medicinally important species.

Effects of KGM and Degradation Products on Appetite Regulation and Energy Expenditure in High-Fat-Diet Mice via the Adipocyte-Hypothalamus Axis.

Konjac glucomannan (KGM), high-viscosity dietary fiber, is utilized in weight management. Previous investigations on the appetite-suppressing effects of KGM have centered on intestinal responses to nutrients and gastric emptying rates, with less focus on downstream hypothalamic neurons of satiety hormones. In our studies, the molecular mechanisms through which KGM and its degradation products influence energy homeostasis via the adipocyte-hypothalamic axis have been examined. It was found that high-viscosity KGM more effectively stimulates enteroendocrine cells to release glucagon-like peptide-1 (GLP-1) and reduces ghrelin production, thereby activating hypothalamic neurons and moderating short-term satiety. Conversely, low-viscosity DKGM has been shown to exhibit stronger anti-inflammatory properties in the hypothalamus, enhancing hormone sensitivity and lowering the satiety threshold. Notably, both KGM and DKGM significantly reduced leptin signaling and fatty acid signaling in adipose tissue and activated brown adipose tissue thermogenesis to suppress pro-opiomelanocortin (POMC) expression and activate agouti-related protein (AgRP) expression, thereby reducing food intake and increasing energy expenditure. Additionally, high-viscosity KGM has been found to activate the adipocyte-hypothalamus axis more effectively than DKGM, thereby promoting greater daily energy expenditure. These findings provide novel insights into the adipocyte-hypothalamic axis for KGM to suppress appetite and reduce weight.

Opioid and dependence-forming medications co-prescription reduction and oversight: the OPIO-CHECK Quality Improvement Project (QIP) protocol and interim analysis.

BACKGROUND: Long-term opioid prescription to manage chronic non-cancer pain (CNCP) is rapidly rising, despite the lacking evidence supporting their safety and efficacy. Co-prescribing opioids with other dependence-forming medications (DFMs) causes fatal side effects. Clinicians are advised to avoid combinations of DFMs and, where suitable, deprescribe to improve patient safety. AIM: To review the number of patients registered to the Grange Medical Centre (Nuneaton, Warwickshire) who are co-prescribed an opioid and either benzodiazepine/gabapentinoid for CNCP and to reduce usage of these DFMs. METHOD: The 'Model for Improvement' is used as a QIP framework. A database search was conducted on 5 October 2023 to identify the cohort of interest. The introduced changes included devising a resource pack outlining the up-to-date non-pharmacological pain management, support channels, and a medication review invitation sent to the identified patients. A pain management template has also been developed to be used by GPs and clinical pharmacists to support the medication review. Guided by the Plan-Do-Study-Act cycle, data will be re-measured to detect incremental changes in practice. RESULTS: In total, 123 patients were receiving co-prescriptions of opioids along with either benzodiazepine/gabapentinoid for CNCP out of the enlisted 12 360 patients. The majority were in the 70-79 years age range. It was also noted that around 66% of patients were females. The QIP's first cycle is currently being implemented. CONCLUSION: This QIP addresses a pressing need to reduce the usage of DFMs. The interim results will guide the change model in the Grange Medical Centre GP surgery and inform scoping of relevant clinical questions to improve patient safety.

Is opium use related to the increased risk of oral cavity cancers? A case-control study in Iran.

BACKGROUND: Oral cavity cancers (OCCs) are the sixth most prevalent cancers in the world. There are strong evidences showing the risk of the cigarette smoking, alcohol use, poor oral hygiene and some types of diets in OCCs; however, few studies explored the relationship between opium and its derivatives (O&D) use and OCCs incidence. The aim of this study was to investigate the relationship between consumption of O&D and the incidence of OCCs. METHODS: In a case-control; 133 patients with OCCs and 266 healthy controls matched by age, sex, and place of residence were included. Data, including cigarette smoking, O&D, alcohol and others tobacco (Nass, pipe and hookah) use and diet, were collected using a structured questionnaire. The relation between the use of O&D and OCCs was evaluated using conditional logistic regression. RESULTS: Opium ever-use was associated with an increased risk of OCCs (Adjusted Odds Ratio (AOR) =2.36, 95 % CI: 1.16-4.78). A dose-response relation was observed between the amount of daily O&D use and OCCs; and the relation was stronger in high users (AOR for low users = 1.38, 95 %CI: 0.58-3.24 and AOR for high users = 4.85, 95 % CI:1.79-13.11). Those who used opium for more than 18 years were highly at risk of OCCs (AOR= 5.04, 95 % CI, 2.00-12.68). Also, OCCs was higher among subjects starting the use of O&D at younger ages (≤ 50 years old vs never users AOR = 3.32, 95 % CI: 1.19-9.23). The smoking method of consuming O&D increased the odds of getting OCCs more than twice (AOR= 2.02, 95 % CI, 1.03-3.94), and using both smoking and oral consumption simultaneously, increased the odds of getting OCCs more than 8 times (AOR= 8.57, 95 % CI, 1.68-43.70). Also, the use of other tobacco products (Nass, pipe and hookah) increases the odds of getting OCCs by 4 times (AOR= 3.90, 95 % CI, 1.12-13.57) CONCLUSIONS: The results showed that opium use is probably a dose related risk factor for oral cavity cancers. Therefore, it is necessary to implement preventive policies to control the use of opioids.

Protein Tyrosine Phosphatase Receptors N and N2 Control Pituitary Melanotroph Development and POMC Expression.

The neuroendocrine marker genes Ptprn and Ptprn2 encode protein tyrosine phosphatase receptors N and N2, 2 members of protein tyrosine phosphatase receptors void of enzymatic activity, and whose function and mechanism of action have not been elucidated. To explore the role(s) of Ptprn and Ptprn2 on the hypothalamic-pituitary-adrenal axis, we used mice in which both genes were knocked out (DKO). The focus in this study was on corticotrophs and melanotrophs from the anterior and intermediate lobes of the pituitary gland, respectively. In both sexes, DKO caused an increase in the expression of the corticotroph/melanotroph genes Pomc and Tbx19 and the melanotroph-specific gene Pax7. We also found in vivo and in vitro increased synthesis and release of beta-endorphin, alpha-melanocyte-stimulating hormone, and ACTH in DKO mice, which was associated with increased serum corticosterone levels and adrenal mass. DKO also increased the expression of other melanotroph-specific genes, but not corticotroph-specific genes. The dopaminergic pathway in the hypothalamus and dopaminergic receptors in melanotrophs were not affected in DKO mice. However, hyperplasia of the intermediate lobe was observed in DKO females and males, accompanied by increased proopiomelanocortin immunoreactivity per cell. These results indicate that protein tyrosine phosphatase receptor type N contributes to hypothalamic-pituitary-adrenal function by being involved in processes governing postnatal melanotroph development and Pomc expression.

Olfactory perceptual interactions of maltol with key food odorants in binary mixtures: Scatter matrix statistical analysis of odor intensity in heterogeneous perceptual situation.

To study the olfactory perceptual interaction of odorants (OPIO) in binary mixtures containing maltol, a simple and efficient analysis method was developed. This method correlated three variables of the binary mixture: two rates of change in perceived odor intensities of two odorants within the binary mixtures, and the degree of overall odor synergy exhibited by the binary mixtures. By creating a three-dimensional scatter matrix with the variables, the changes in odor intensity of the binary mixture due to OPIO were visualized. The results revealed that the proportions of mutual antagonism, opposite effect, mutual independence, and mutual synergy in the binary mixtures were 64.7%, 32.9%, 1.9%, and 0.5%, respectively. The odor of maltol was mainly masked, and those of esters (68%), aldehydes and ketones (33%) in the mixture were enhanced. In terms of overall odor intensity, 67% of cases involved partial addition, followed by 22.2% overshadowing, and 19.6% stronger component effect.

GABAergic disinhibition from the BNST to PNOCARC neurons promotes HFD-induced hyperphagia.

Activation of prepronociceptin (PNOC)-expressing neurons in the arcuate nucleus (ARC) promotes high-fat-diet (HFD)-induced hyperphagia. In turn, PNOCARC neurons can inhibit the anorexic response of proopiomelanocortin (POMC) neurons. Here, we validate the necessity of PNOCARC activity for HFD-induced inhibition of POMC neurons in mice and find that PNOCARC-neuron-dependent inhibition of POMC neurons is mediated by gamma-aminobutyric acid (GABA) release. When monitoring individual PNOCARC neuron activity via Ca2+ imaging, we find a subpopulation of PNOCARC neurons that is inhibited upon gastrointestinal calorie sensing and disinhibited upon HFD feeding. Combining retrograde rabies tracing and circuit mapping, we find that PNOC neurons from the bed nucleus of the stria terminalis (PNOCBNST) provide inhibitory input to PNOCARC neurons, and this inhibitory input is blunted upon HFD feeding. This work sheds light on how an increase in caloric content of the diet can rewire a neuronal circuit, paving the way to overconsumption and obesity development.

Therapeutic Strategies Against Metabolic Imbalance in a Male Mouse Model With 5-HT2CR Loss-of-Function.

The serotonin 2C receptor (5-HT2CR)-melanocortin pathway plays well-established roles in the regulation of feeding behavior and body weight homeostasis. Dysfunctions in this system, such as loss-of-function mutations in the Htr2c gene, can lead to hyperphagia and obesity. In this study, we aimed to investigate the potential therapeutic strategies for ameliorating hyperphagia, hyperglycemia, and obesity associated with a loss-of-function mutation in the Htr2c gene (Htr2cF327L/Y). We demonstrated that reexpressing functional 5-HT2CR solely in hypothalamic pro-opiomelanocortin (POMC) neurons is sufficient to reduce food intake and body weight in Htr2cF327L/Y mice subjected to a high-fat diet (HFD). In addition, 5-HT2CR expression restores the responsiveness of POMC neurons to lorcaserin, a selective agonist for 5-HT2CR. Similarly, administration of melanotan II, an agonist of the melanocortin receptor 4 (MC4R), effectively suppresses feeding and weight gain in Htr2cF327L/Y mice. Strikingly, promoting wheel-running activity in Htr2cF327L/Y mice results in a decrease in HFD consumption and improved glucose homeostasis. Together, our findings underscore the crucial role of the melanocortin system in alleviating hyperphagia and obesity related to dysfunctions of the 5-HT2CR, and further suggest that MC4R agonists and lifestyle interventions might hold promise in counteracting hyperphagia, hyperglycemia, and obesity in individuals carrying rare variants of the Htr2c gene.

Development of a two-layer machine learning model for the forensic application of legal and illegal poppy classification based on sequence data.

Poppies are beneficial plants with a variety of applications, including medicinal, edible, ornamental, and industrial purposes. Some Papaver species are forensically significant plants because they contain opium, a narcotic substance. Internationally trafficked species of illegal poppies are being identified by DNA barcoding employing multiple markers in response to their forensic value. However, effective markers for precise species identification of legal and illegal poppies are still under discussion, with research on illegal poppies focusing on Papaver somniferum L., and species identification studies of Papaver bracteatum and Papaver setigerum DC. still lacking. As a result, in order to evaluate the performance of genetic markers and classify their DNA sequences in the genus Papaver, this study developed the first machine learning-based two-layer model, in which the first layer classifies legal and illegal poppies from the given sequence and the second layer identifies species of illegal poppies using their sequences. We constructed the dataset and investigated biological features from four markers, internal transcribed spacer 1 (ITS1), internal transcribed spacer 2 (ITS2), transfer RNA Leucine (trnL), transfer RNA Leucine - transfer RNA Phenylalanine intergenic spacer (trnL-trnF intergenic spacer) and their combination, using four machine learning algorithms, K-nearest neighbor (KNN), Naïve Bayes (NB), extreme gradient boost (XGBoost) and Random Forest (RF). According to our findings, for Layer 1 to classify legal and illegal poppies, KNN-based models using combined ITS region achieved the greatest performance of accuracy 0.846 and 0.889 using training and test sets, respectively. Additionally, for Layer 2 to identify illegal poppy species, KNN-based models using combined ITS region achieved the best performance of 0.833 and 1.000 for using training and test sets, respectively. To validate the model, the combined ITS region, which includes ITS 1 and 2 sequences, from blind poppy samples were used as a case study, with the Layer 1 correctly classifying legal and illegal poppies with over 0.830 accuracy. Layer 2 correctly identified P. setigerum DC., however, only one of the three P. somniferum L. species was accurately identified. Nevertheless, our research shows that machine learning can be used to classify and identify legal and illegal poppy species using DNA barcodes which can then be used as an efficient and effective forensic tool for improved law enforcement and a safer society.

Obesity Alters POMC and Kisspeptin Neuron Cross Talk Leading to Reduced Luteinizing Hormone in Male Mice.

Obesity is associated with hypogonadism in males, characterized by low testosterone and sperm number. Previous studies determined that these stem from dysregulation of hypothalamic circuitry that regulates reproduction, by unknown mechanisms. Herein, we used mice fed chronic high-fat diet, which mimics human obesity, to determine mechanisms of impairment at the level of the hypothalamus, in particular gonadotropin-releasing hormone (GnRH) neurons that regulate luteinizing hormone (LH), which then regulates testosterone. Consistent with obese humans, we demonstrated lower LH, and lower pulse frequency of LH secretion, but unchanged pituitary responsiveness to GnRH. LH pulse frequency is regulated by pulsatile GnRH secretion, which is controlled by kisspeptin. Peripheral and central kisspeptin injections, and DREADD-mediated activation of kisspeptin neurons, demonstrated that kisspeptin neurons were suppressed in obese mice. Thus, we investigated regulators of kisspeptin secretion. We determined that the LH response to NMDA was lower in obese mice, corresponding to fewer glutamate receptors in kisspeptin neurons, which may be critical for kisspeptin synchronization. Given that kisspeptin neurons also interact with anorexigenic POMC neurons, which are affected by obesity, we examined their cross talk, and determined that the LH response to either DREADD-mediated activation of POMC neurons or central injection of αMSH, a product of POMC, is abolished in obese mice. This was accompanied by diminished levels of αMSH receptor, MC4R, in kisspeptin neurons. Together, our studies determined that obesity leads to the downregulation of receptors that regulate kisspeptin neurons, which is associated with lower LH pulse frequency, leading to lower LH and hypogonadism.

Seipin Deficiency Leads to Energy Dyshomeostasis via Inducing Hypothalamic Neuroinflammation and Aberrant Expression of Neuropeptides.

Seipin is a key regulator of lipid metabolism, the deficiency of which leads to severe lipodystrophy. Hypothalamus is the pivotal center of brain that modulates appetite and energy homeostasis, where Seipin is abundantly expressed. Whether and how Seipin deficiency leads to systemic metabolic disorders via hypothalamus-involved energy metabolism dysregulation remains to be elucidated. In the present study, we demonstrated that Seipin-deficiency induced hypothalamic inflammation, reduction of anorexigenic pro-opiomelanocortin (POMC), and elevation of orexigenic agonist-related peptide (AgRP). Importantly, administration of rosiglitazone, a thiazolidinedione antidiabetic agent, rescued POMC and AgRP expression, suppressed hypothalamic inflammation, and restored energy homeostasis in Seipin knockout mice. Our findings offer crucial insights into the mechanism of Seipin deficiency-associated energy imbalance and indicates that rosiglitazone could serve as potential intervening agent towards metabolic disorders linked to Seipin.

[Source Apportionment of Morphine in Wastewater].

It is a new approach to identify legal or illegal use of morphine through information on municipal wastewater. However, the sources of morphine in wastewater are complex, and distinguishing the contribution of different sources has become a key issue. A total of 262 influent samples from 61 representative wastewater treatment plants in a typical city were collected from October 2022 to March 2023. The concentrations of morphine, codeine, thebaine, papaverine, noscapine, and monoacetylmorphine were analyzed in wastewater and poppy straws. Combined with the proportion of alkaloids in poppy straws, the source analysis of alkaloids in wastewater was analyzed using the ratio method and positive matrix factorization model (PMF). Only five alkaloids were detected in wastewater, and monoacetylmorphine, a metabolite of heroin, was not detected. The concentrations of morphine and codeine were significantly higher than those of noscapine, papaverine, and thebaine. By constructing the ratios of codeine/(morphine + codeine) and noscapine/(noscapine + codeine), the source of poppy straw could be qualitatively distinguished. The PMF results showed that three sources of morphine for medical use, poppy straw, and codeine contributed 44.9%, 43.7%, and 9.4%, respectively. The different sources varied in these months due to the COVID-19 and influenza A outbreaks, in which the use of drugs containing poppy straws and codeine was the main source, whereas the use of morphine analgesics remained relatively stable. Inventory analysis further demonstrated the reliability of the source contributions from the PMF model, and morphine was not abused in this city.

Long-Term Effects of Opium Consumption Following Percutaneous Coronary Intervention: A 10-year Follow-Up Study.

Background: Opium consumption has been an overlooked health issue in the Iranian population, and the prognostic role of opium consumption in patients undergoing coronary revascularization is unknown. Hypothesis: We aimed to assess the association between opium consumption and long-term cardiovascular outcomes after percutaneous coronary intervention (PCI). Methods: We screened 2203 consecutive patients who underwent elective PCI between April 2009 and April 2010 at Tehran Heart Center. Exclusion criteria were unsuccessful PCI, non-elective PCI, and missing opium use data. Opium consumption was defined as self-reported ever use of any traditional opium substances. Outcomes of interest were all-cause mortality and a composite of major adverse cardiac and cerebrovascular events (MACCE). The association between opium use and study outcomes was evaluated using the inverse probability of treatment weighting (IPTW) method. Cumulative hazard curves were demonstrated to further assess the association visually. Furthermore, the effect of opium consumption on individual components of MACCE was evaluated in a competing risk setting. Results: A total of 2025 elective PCI patients were included (age: 58.7 ± 10.67, 29.1% women), among whom 297 (14.6%) patients were opium users. After a median follow-up of 10.7 years, opium consumption was associated with a higher risk of all-cause mortality (IPTW-hazard ratio [HR] = 1.705, 95% CI: 1.125-2.585; P = 0.012) and MACCE (IPTW-HR = 1.578, 95% CI: 1.156-2.153; P = 0.004). The assessment of MACCE components suggested a non-significant borderline trend for higher non-fatal myocardial infarction (IPTW-sub-distribution HR [SHR] = 1.731, 95% CI: 0.928-3.231; P = 0.084) and mortality (IPTW-SHR = 1.441, 95% CI: 0.884-2.351; P = 0.143) among opium users. Conclusions: Opium consumption is associated with a more than 50% increase in long-term risk of mortality and MACCE in patients undergoing PCI. These findings accentuate the importance of preventive strategies to quit opium addiction in this population.

Single cell tracing of Pomc neurons reveals recruitment of 'Ghost' subtypes with atypical identity in a mouse model of obesity.

The hypothalamus contains a remarkable diversity of neurons that orchestrate behavioural and metabolic outputs in a highly plastic manner. Neuronal diversity is key to enabling hypothalamic functions and, according to the neuroscience dogma, it is predetermined during embryonic life. Here, by combining lineage tracing of hypothalamic pro-opiomelanocortin (Pomc) neurons with single-cell profiling approaches in adult male mice, we uncovered subpopulations of 'Ghost' neurons endowed with atypical molecular and functional identity. Compared to 'classical' Pomc neurons, Ghost neurons exhibit negligible Pomc expression and are 'invisible' to available neuroanatomical approaches and promoter-based reporter mice for studying Pomc biology. Ghost neuron numbers augment in diet-induced obese mice, independent of neurogenesis or cell death, but weight loss can reverse this shift. Our work challenges the notion of fixed, developmentally programmed neuronal identities in the mature hypothalamus and highlight the ability of specialised neurons to reversibly adapt their functional identity to adult-onset obesogenic stimuli.

Food perception promotes phosphorylation of MFFS131 and mitochondrial fragmentation in liver.

Liver mitochondria play a central role in metabolic adaptations to changing nutritional states, yet their dynamic regulation upon anticipated changes in nutrient availability has remained unaddressed. Here, we found that sensory food perception rapidly induced mitochondrial fragmentation in the liver through protein kinase B/AKT (AKT)-dependent phosphorylation of serine 131 of the mitochondrial fission factor (MFFS131). This response was mediated by activation of hypothalamic pro-opiomelanocortin (POMC)-expressing neurons. A nonphosphorylatable MFFS131G knock-in mutation abrogated AKT-induced mitochondrial fragmentation in vitro. In vivo, MFFS131G knock-in mice displayed altered liver mitochondrial dynamics and impaired insulin-stimulated suppression of hepatic glucose production. Thus, rapid activation of a hypothalamus-liver axis can adapt mitochondrial function to anticipated changes of nutritional state in control of hepatic glucose metabolism.

Inhibition of Crif1 protects fatty acid-induced POMC neuron-like cell-line damage by increasing CPT-1 function.

Hypothalamic proopiomelanocortin (POMC) neurons are sensors of signals that reflect the energy stored in the body. Inducing mild stress in proopiomelanocortin neurons protects them from the damage promoted by the consumption of a high-fat diet, mitigating the development of obesity; however, the cellular mechanisms behind these effects are unknown. Here, we induced mild stress in a proopiomelanocortin neuron cell line by inhibiting Crif1. In proopiomelanocortin neurons exposed to high levels of palmitate, the partial inhibition of Crif1 reverted the defects in mitochondrial respiration and ATP production; this was accompanied by improved mitochondrial fusion/fission cycling. Furthermore, the partial inhibition of Crif1 resulted in increased reactive oxygen species production, increased fatty acid oxidation, and reduced dependency on glucose for mitochondrial respiration. These changes were dependent on the activity of CPT-1. Thus, we identified a CPT-1-dependent metabolic shift toward greater utilization of fatty acids as substrates for respiration as the mechanism behind the protective effect of mild stress against palmitate-induced damage of proopiomelanocortin neurons.NEW & NOTEWORTHY Saturated fats can damage hypothalamic neurons resulting in positive energy balance, and this is mitigated by mild cellular stress; however, the mechanisms behind this protective effect are unknown. Using a proopiomelanocortin cell line, we show that under exposure to a high concentration of palmitate, the partial inhibition of the mitochondrial protein Crif1 results in protection due to a metabolic shift warranted by the increased expression and activity of the mitochondrial fatty acid transporter CPT-1.

Optogenetic induction of chronic glucocorticoid exposure in early-life leads to blunted stress-response in larval zebrafish.

Early life stress (ELS) exposure alters stress susceptibility in later life and affects vulnerability to stress-related disorders, but how ELS changes the long-lasting responsiveness of the stress system is not well understood. Zebrafish provides an opportunity to study conserved mechanisms underlying the development and function of the stress response that is regulated largely by the neuroendocrine hypothalamus-pituitary-adrenal/interrenal (HPA/I) axis, with glucocorticoids (GC) as the final effector. In this study, we established a method to chronically elevate endogenous GC levels during early life in larval zebrafish. To this end, we employed an optogenetic actuator, beggiatoa photoactivated adenylyl cyclase, specifically expressed in the interrenal cells of zebrafish and demonstrate that its chronic activation leads to hypercortisolaemia and dampens the acute-stress evoked cortisol levels, across a variety of stressor modalities during early life. This blunting of stress-response was conserved in ontogeny at a later developmental stage. Furthermore, we observe a strong reduction of proopiomelanocortin (pomc)-expression in the pituitary as well as upregulation of fkbp5 gene expression. Going forward, we propose that this model can be leveraged to tease apart the mechanisms underlying developmental programming of the HPA/I axis by early-life GC exposure and its implications for vulnerability and resilience to stress in adulthood.