Hypothalamic astrocyte NAD+ salvage pathway mediates the coupling of dietary fat overconsumption in a mouse model of obesity.

Nicotinamide adenine dinucleotide (NAD)+ serves as a crucial coenzyme in numerous essential biological reactions, and its cellular availability relies on the activity of the nicotinamide phosphoribosyltransferase (NAMPT)-catalyzed salvage pathway. Here we show that treatment with saturated fatty acids activates the NAD+ salvage pathway in hypothalamic astrocytes. Furthermore, inhibition of this pathway mitigates hypothalamic inflammation and attenuates the development of obesity in male mice fed a high-fat diet (HFD). Mechanistically, CD38 functions downstream of the NAD+ salvage pathway in hypothalamic astrocytes burdened with excess fat. The activation of the astrocytic NAMPT-NAD+-CD38 axis in response to fat overload induces proinflammatory responses in the hypothalamus. It also leads to aberrantly activated basal Ca2+ signals and compromised Ca2+ responses to metabolic hormones such as insulin, leptin, and glucagon-like peptide 1, ultimately resulting in dysfunctional hypothalamic astrocytes. Our findings highlight the significant contribution of the hypothalamic astrocytic NAD+ salvage pathway, along with its downstream CD38, to HFD-induced obesity.

Hypothalamic AMP-Activated Protein Kinase as a Whole-Body Energy Sensor and Regulator.

5´-Adenosine monophosphate (AMP)-activated protein kinase (AMPK), a cellular energy sensor, is an essential enzyme that helps cells maintain stable energy levels during metabolic stress. The hypothalamus is pivotal in regulating energy balance within the body. Certain neurons in the hypothalamus are sensitive to fluctuations in food availability and energy stores, triggering adaptive responses to preserve systemic energy equilibrium. AMPK, expressed in these hypothalamic neurons, is instrumental in these regulatory processes. Hypothalamic AMPK activity is modulated by key metabolic hormones. Anorexigenic hormones, including leptin, insulin, and glucagon-like peptide 1, suppress hypothalamic AMPK activity, whereas the hunger hormone ghrelin activates it. These hormonal influences on hypothalamic AMPK activity are central to their roles in controlling food consumption and energy expenditure. Additionally, hypothalamic AMPK activity responds to variations in glucose concentrations. It becomes active during hypoglycemia but is deactivated when glucose is introduced directly into the hypothalamus. These shifts in AMPK activity within hypothalamic neurons are critical for maintaining glucose balance. Considering the vital function of hypothalamic AMPK in the regulation of overall energy and glucose balance, developing chemical agents that target the hypothalamus to modulate AMPK activity presents a promising therapeutic approach for metabolic conditions such as obesity and type 2 diabetes mellitus.

Survival pattern of metastatic renal cell carcinoma patients according to WHO/ISUP grade: a long-term multi-institutional study.

The World Health Organization/International Society of Urological Pathology (WHO/ISUP) grading of renal cell carcinoma (RCC) is classified from grade 1-4, regardless of subtype. The National Comprehensive Cancer Network (NCCN) guidelines (2022) state that if there is an adverse pathological feature, such as grade 3 or higher RCC in stage 1 patients, more rigorous follow-up imaging is recommended. However, the RCC guidelines do not provide specific treatment or follow-up policies by tumor grade. Therefore, this study attempted to find out whether tumor grade affects survival rates in patients with metastatic RCC. The Korean Renal Cancer Study Group (KRoCS) database includes 3108 patients diagnosed with metastatic RCC between September 1992 and February 2017, with treatment methods, progression, and survival data collected from 11 tertiary hospitals. To obtain information on survival rates or causes of death, we utilized the Korea National Statistical Office database and institutional medical records. Data were accessed for research purpose on June, 2023. We then reviewed these sources to gather comprehensive and reliable data on the outcomes of our study cohort. This database was retrospectively analyzed, and out of 3108 metastatic RCC patients, 911 had been identified as WHO/ISUP grade. Grades were classified into either a low-grade (WHO/ISUP grade 1-2) or a high-grade group (WHO/ISUP grade 3-4). The patients were then analyzed related to progression and overall survival (OS). In metastatic clear cell RCC patients, the 1-year OS rate was 69.4% and the median OS was 17.0 months (15.5-18.5) followed up to 203.6 months. When comparing the patient groups, 119 low-grade and 873 high-grade cases were identified. No baseline difference was observed between the two groups, except that the high-grade group had a higher ECOG 1 ratio of 50.4% compared with 34.5% for the low-grade group (p = 0.009). There was a significant difference in OS between high-grade and low-grade groups. OS was 16.0 months (14.6-17.4) in the high-grade group and 28.0 months (21.1-34.9) in the low-grade group (p < 0.001). However, there was no difference in progression-free survival (PFS) rates with 9.0 months (8.0-10.0) for the high-grade group and 10.0 months (6.8-13.2) for the low-grade group (p = 0.377) in first-line treatment. In multivariable analysis, WHO/ISUP grade was a risk factor (HR = 1.511[1.135-2.013], p = 0.005) that influenced the OS. In conclusion, WHO/ISUP grade is a major data source that can be used as a ubiquitous marker of metastatic RCC in pre-IO era. Depending on whether the RCC is high or low grade, the follow-up schedule will need to be tailored according to grade, with higher-grade patients needing more active treatment as it can not only affect the OS in the previously known localized/locoregional recurrence but also the metastatic RCC patient.

Oxide Semiconductor Heterojunction Transistor with Negative Differential Transconductance for Multivalued Logic Circuits.

Multivalued logic (MVL) technology is a promising solution for improving data density and reducing power consumption in comparison to complementary metal-oxide-semiconductor (CMOS) technology. Currently, heterojunction transistors (TRs) with negative differential transconductance (NDT) characteristics, which play an important role in the function of MVL circuits, adopt organic or 2D semiconductors as active layers, but it is still difficult to apply conventional CMOS processes. Herein, we demonstrate an oxide semiconductor (OS) heterojunction TR with NDT characteristics composed of p-type copper(I) oxide (Cu2O) and n-type indium gallium zinc oxide (IGZO) using the conventional CMOS manufacturing processes. The electrical characteristics of the fabricated device exhibit a high Ion/Ioff ratio (∼3 × 103), wide NDT ranges (∼29 V), and high peak-to-valley current ratios (PVCR ≈ 25). The electrical properties of 15 devices were measured, confirming uniform performance in the PVCR, NDT range, and Ion/Ioff ratio. We analyze the device operation by varying the source/drain (S/D) position and changing the device geometry and the thickness of the Cu2O layer. Additionally, we demonstrate heterojunction ambipolar TR to elucidate the transport mechanism of NDT devices at a high gate voltage (VGS). To confirm the feasibility of the MVL circuit, we present a ternary inverter with three clearly expressed logic states that have a long intermediate state and greater margin of error induced by wide NDT regions and high PVCR.

Transcriptomic profiling and the first spatial expression analysis of candidate genes in the salivary gland of the East Asian medicinal leech, Hirudo nipponia.

Hirudo nipponia, a blood-sucking leech native to East Asia, possesses a rich repertoire of active ingredients in its saliva, showcasing significant medical potential due to its anticoagulant, anti-inflammatory, and antibacterial effects against human diseases. Despite previous studies on the transcriptomic and proteomic characteristics of leech saliva, which have identified medicinal compounds, our knowledge of tissue-specific transcriptomes and their spatial expression patterns remains incomplete. In this study, we conducted an extensive transcriptomic profiling of the salivary gland tissue in H. nipponia based on de novo assemblies of tissue-specific transcriptomes from the salivary gland, teeth, and general head region. Through gene ontology (GO) analysis and hierarchical clustering, we discovered a novel set of anti-coagulant factors-i.e., Hni-Antistasin, Hni-Ghilanten, Hni-Bdellin, Hni-Hirudin-as well as a previously unrecognized immune-related gene, Hni-GLIPR1 and uncharacterized salivary gland specific transcripts. By employing in situ hybridization, we provided the first visualization of gene expression sites within the salivary gland of H. nipponia. Our findings expand on our understanding of transcripts specifically expressed in the salivary gland of blood-sucking leeches, offering valuable resources for the exploration of previously unidentified substances with medicinal applications.

ß-Carotene and ß-apo-8'-carotenal contents in processed foods in Korea.

A robust and rapid HPLC method for ß-carotene and ß-apo-8'-carotenal analyses in various processed foods was developed. The analysis method was validated for low-fat, moderate-fat, and high-fat food matrices. The two carotenoids were identified by LC-MS/MS. The detection limits for ß-carotene and ß-apo-8'-carotenal in the three food matrices were 0.08-0.27 µg/g and 0.09-0.18 µg/g, respectively. The inter- and intra-day accuracy and precision were in accordance with the Codex guidelines. The validated method was applied to 57 processed food samples, possibly containing ß-carotene and ß-apo-8'-carotenal, obtained in Korea. The detected ß-carotene and ß-apo-8'-carotenal levels in the samples ranged from not detected (ND) to 6.92 µg/g and ND to 1.63 µg/g, respectively. Chocolate and cheese samples had the highest ß-carotene and ß-apo-8'-carotenal levels, respectively. Notably, several samples with no labeled carotenoid additives contained ß-carotene. Moreover, the developed analytical method was compatible with various processed food matrices. Supplementary Information: The online version contains supplementary material available at 10.1007/s10068-023-01285-2.

Low humoral and cellular immune responses early after breakthrough infection may contribute to severe COVID-19.

Background: Little is known about the immune determinants for severe coronavirus disease 2019 (COVID-19) in individuals vaccinated against severe acute respiratory syndrome coronavirus 2. We therefore attempted to identify differences in humoral and cellular immune responses between patients with non-severe and severe breakthrough COVID-19. Methods: We prospectively enrolled hospitalized patients with breakthrough COVID-19 (severe and non-severe groups) and uninfected individuals who were vaccinated at a similar time (control group). Severe cases were defined as those who required oxygen therapy while hospitalized. Enzyme-linked immunosorbent assays and flow cytometry were used to evaluate humoral and cellular immune responses, respectively. Results: Anti-S1 IgG titers were significantly lower in the severe group than in the non-severe group within 1 week of symptom onset and higher in the non-severe group than in the control group. Compared with the control group, the cellular immune response tended to be diminished in breakthrough cases, particularly in the severe group. In multivariate analysis, advanced age and low anti-S1 IgG titer were associated with severe breakthrough COVID-19. Conclusions: Severe breakthrough COVID-19 might be attributed by low humoral and cellular immune responses early after infection. In the vaccinated population, delayed humoral and cellular immune responses may contribute to severe breakthrough COVID-19.

Metformin ameliorates olanzapine-induced disturbances in POMC neuron number, axonal projection, and hypothalamic leptin resistance.

Antipsychotics have been widely accepted as a treatment of choice for psychiatric illnesses such as schizophrenia. While atypical antipsychotics such as aripiprazole are not associated with obesity and diabetes, olanzapine is still widely used based on the anticipation that it is more effective in treating severe schizophrenia than aripiprazole, despite its metabolic side effects. To address metabolic problems, metformin is widely prescribed. Hypothalamic proopiomelanocortin (POMC) neurons have been identified as the main regulator of metabolism and energy expenditure. Although the relation between POMC neurons and metabolic disorders is well established, little is known about the effects of olanzapine and metformin on hypothalamic POMC neurons. In the present study, we investigated the effect of olanzapine and metformin on the hypothalamic POMC neurons in female mice. Olanzapine administration for 5 days significantly decreased Pomc mRNA expression, POMC neuron numbers, POMC projections, and induced leptin resistance before the onset of obesity. It was also observed that coadministration of metformin with olanzapine not only increased POMC neuron numbers and projections but also improved the leptin response of POMC neurons in the olanzapine-treated female mice. These findings suggest that olanzapine-induced hypothalamic POMC neuron abnormality and leptin resistance, which can be ameliorated by metformin administration, are the possible causes of subsequent hyperphagia. [BMB Reports 2022; 55(6): 293-298].

Plum Prevents Intestinal and Hepatic Inflammation in the Acute and Chronic Models of Dextran Sulfate Sodium-Induced Mouse Colitis.

SCOPE: Inflammatory bowel disease (IBD), including ulcerative colitis (UC), is a chronic recurrent inflammatory disease of the digestive tract and increases the risk of colon cancer. METHOD AND RESULTS: This study evaluates the effects of dietary intervention with freeze-dried plum (FDP), a natural antioxidant and anti-inflammatory fruit with no toxicity on dextran sulfate sodium (DSS)-induced acute and chronic experimental colitis in a mouse model and studies the molecular mechanisms of protection through the gut-liver axis. The results show that FDP decreases the levels of inflammatory mediators, which is a nitrative stress biomarker in both acute and chronic models. FDP markedly reduces DSS-induced injury to the colonic epithelium in both acute and chronic models. In addition, FDP significantly decreases the levels of pro-oxidant markers such as CYP2E1, iNOS, and nitrated proteins (detected by anti-3-NT antibody) in DSS-induced acute and chronic colonic injury models. Furthermore, FDP markedly reduces markers of liver injury such as serum ALT/AST, antioxidant markers, and inflammatory mediators in DSS-induced acute and chronic colonic injury. CONCLUSION: These results demonstrate that the FDP exhibits a protective effect on DSS-induced acute and chronic colonic and liver injury through the gut-liver axis via antioxidant and anti-inflammatory properties.

Mechanisms of Weight Control by Primary Cilia.

A primary cilium, a hair-like protrusion of the plasma membrane, is a pivotal organelle for sensing external environmental signals and transducing intracellular signaling. An interesting linkage between cilia and obesity has been revealed by studies of the human genetic ciliopathies Bardet-Biedl syndrome and Alström syndrome, in which obesity is a principal manifestation. Mouse models of cell type-specific cilia dysgenesis have subsequently demonstrated that ciliary defects restricted to specific hypothalamic neurons are sufficient to induce obesity and hyperphagia. A potential mechanism underlying hypothalamic neuron cilia-related obesity is impaired ciliary localization of G protein-coupled receptors involved in the regulation of appetite and energy metabolism. A well-studied example of this is melanocortin 4 receptor (MC4R), mutations in which are the most common cause of human monogenic obesity. In the paraventricular hypothalamus neurons, a blockade of ciliary trafficking of MC4R as well as its downstream ciliary signaling leads to hyperphagia and weight gain. Another potential mechanism is reduced leptin signaling in hypothalamic neurons with defective cilia. Leptin receptors traffic to the periciliary area upon leptin stimulation. Moreover, defects in cilia formation hamper leptin signaling and actions in both developing and differentiated hypothalamic neurons. The list of obesity-linked ciliary proteins is expending and this supports a tight association between cilia and obesity. This article provides a brief review on the mechanism of how ciliary defects in hypothalamic neurons facilitate obesity.

Effect of Characterized Green Tea Extraction Methods and Formulations on Enzymatic Starch Hydrolysis and Intestinal Glucose Transport.

The purpose of the current study was to investigate the effect of various characterized green tea extracts (GTEs) according to extraction methods on enzymatic starch hydrolysis and intestinal glucose transport. Codigestion of wheat starch with water extract (WGT) or ethanol extract formulated with green tea polysaccharides and flavonols (CATEPLUS) produced 3.4-3.5 times higher resistant starch (RS) than wheat starch only. Its microstructures were changed to spherical shapes and smooth surfaces as shown by scanning electron microscopy (SEM) results. According to Fourier transform infrared (FT-IR) spectra, the absorption peak of O-H stretching was red-shifted in WGT or CATEPLUS. The results confirmed that hydrogen bonds were formed between starch granules and polysaccharides in WGT or CATEPLUS. Intestinal glucose transport subsequently measured after in vitro digestion was mostly suppressed in CATEPLUS. Gene expression of the glucose transporter protein, particularly SGLT1, was significantly inhibited by addition of CATEPLUS (p < 0.05). Results from the current study suggest that co-intake of green tea extracts formulated with green tea polysaccharides and flavonols could be a potentially useful means to delay blood glucose absorption when consuming starchy foods.

Characterized Polysaccharides from Green Tea Inhibited Starch Hydrolysis and Glucose Intestinal Uptake by Inducing Microstructural Changes of Wheat Starch.

The purpose of the current study was to investigate the effect of green tea ethanol extract (GTE) and polysaccharide fractions from green tea (PFGs) on the hydrolysis of wheat starch, microstructural changes, and intestinal transport of glucose. The amount of resistant starch (RS) was significantly lowered in the water-soluble polysaccharide (WSP), water-soluble polysaccharide-pectinase (WSP-P), and water-insoluble polysaccharide-alkali soluble (WISP-Alk-Soluble; p < 0.05). The microstructures of gelatinized wheat starch granules with WSP, WSP-P, and WISP-Alk-Soluble were spherical with small cracks. The amount of intestinal transported glucose from digested wheat starch was 2.12-3.50 times lower than the control group. The results from the current study suggest that water- and alkali-soluble PFGs could be potential ingredients to lower starch hydrolysis as well as to control the postprandial blood glucose level when foods that contain starch are consumed.

Impact of soy lecithin, zinc oxide, and methylsulfonylmethane, as excipient ingredients, on the bioaccessibility and intestinal transport of branched-chain amino acids from animal and plant protein mixtures.

To maximize the biological activity of branched-chain amino acids (BCAAs), it is necessary to find a new excipient agent to increase the bioavailability of BCAAs in protein mixtures. The aim of the current study was to investigate the effects of soy lecithin (SLC), zinc oxide (ZnO), and methylsulfonylmethane (MSM) on the bioaccessibility and intestinal transport of BCAAs from animal and plant protein mixtures (PMs) via an in vitro digestion model with human intestinal epithelial (Caco-2) cells. The bioaccessibility of total BCAAs in PMs considerably increased by 107.51 ± 1.50% with the addition of SLC, and the combined effects of SLC, ZnO, and MSM on enhancing the bioaccessibility of total BCAAs was observed (107.14 ± 0.18%). Interestingly, SLC showed a major role in binding bile acid, showing 65.78 ± 1.66% of binding capacity. Intestinal transport of BCAAs was measured to be at 100.48, 110.86, and 130.29 µg mL-1 for leucine, isoleucine, and valine, respectively, in PMs with SLC + ZnO + MSM, and it eventually amplified the amount of the total transported BCAAs (341.63 ± 6.34 µg mL-1), which was about 8.72 times higher than that of PM only. The cellular integrity of digesta-treated Caco-2 cells tended to decrease according to the incubation time, but it was recovered in the treatment of PM + SLC + ZnO + MSM, and nearly reached the control levels with 92.82 ± 0.53%. Results from the current study suggest that the co-consumption of proteins equally consisting of plant and animal sources with SLC, ZnO, and MSM could improve the bioavailability of total BCAAs, resulting in the improvement of health benefits.

Erratum to: Common and differential effects of docosahexaenoic acid and eicosapentaenoic acid on helper T-cell responses and associated pathways.

[Erratum to: BMB Reports 2021; 54(5): 278-283, PMID: 33972011] In the originally published version of this article, there was an error in the Supplementary information. Fig. 1 as following image was missing in the Supplementary Information. The Supplementary file in the original version has now been updated to include the corrected. We apologize for any inconvenience that this may have caused.

Acupuncture combined with multidisciplinary care for recovery after traumatic multiple rib fractures: a prospective feasibility cohort study.

INTRODUCTION: Acute pain significantly delays early physiological recovery and results in chronic functional disability in patients with traumatic multiple rib fractures (MRFs). This prospective cohort study aimed to investigate the feasibility of acupuncture combined with multidisciplinary care during recovery in patients with traumatic MRFs. METHODS: Twenty patients with traumatic MRFs who were admitted to a regional trauma centre in South Korea were enrolled. A combination of acupuncture and multidisciplinary inpatient ward management was provided at the trauma ward. Patients were permitted to continue acupuncture treatments at outpatient clinics for 3 months after the traumatic events. Clinical outcomes, including pain, acute physiological recovery, quality of life, patient satisfaction with the care provided, respiratory function and use of opioids, were evaluated up to 6 months after trauma. RESULTS: Seventeen (85%) participants completed the 6-month follow-up. One patient withdrew consent during admission due to discomfort after three sessions of acupuncture. The proportion of patients with above-moderate level of pain decreased from 95% at baseline to 41% at 6 months. Quality of life appeared to deteriorate consistently throughout the study period. Around 80% of respondents expressed satisfaction with the acupuncture treatments and stated that they found acupuncture to be acceptable. Over 94% of respondents reported slight or considerable improvement. CONCLUSION: The provision of acupuncture combined with multidisciplinary care for recovery in patients with traumatic MRFs was feasible in a regional trauma centre in South Korea. Randomised trials are needed to investigate the role of acupuncture combined with multidisciplinary care in the future. TRIAL REGISTRATION NUMBER: KCT0002911 (Clinical Research Information Service).

Profiling of In Vitro Bioaccessibility and Intestinal Uptake of Flavonoids after Consumption of Commonly Available Green Tea Types.

The aim of this study was to profile the bioaccessibility and intestinal absorption of epicatechins and flavonols in different forms of green tea and its formulation: loose leaf tea, powdered tea, 35% catechins containing GTE, and GTE formulated with green tea-derived polysaccharide and flavonols (CATEPLUS™). The bioaccessibillity and intestinal absorption of epicatechins and flavonols was investigated by using an in vitro digestion model system with Caco-2 cells. The bioaccessibility of total epicatechins in loose leaf tea, powdered tea, GTE, and CATEPLUS™ was 1.27%, 2.30%, 22.05%, and 18.72%, respectively, showing that GTE and CATEPLUS™ had significantly higher bioaccessibility than powdered tea and loose leaf tea. None of the flavonols were detected in powdered tea and loose leaf tea, but the bioaccessibility of the total flavonols in GTE and CATEPLUS™ was 85.74% and 66.98%, respectively. The highest intestinal absorption of epicatechins was found in CATEPLUS™ (171.39 ± 5.39 ng/mg protein) followed by GTE (57.38 ± 9.31), powdered tea (3.60 ± 0.67), and loose leaf tea (2.94 ± 1.03). The results from the study suggest that formulating green tea extracts rich in catechins with second components obtained from green tea processing could enhance the bioavailability of epicatechins.

Seizure during hyperbaric oxygen therapy: experience at a single academic hospital in Korea.

Background: Hyperbaric oxygen (HBO2) therapy is a safe and well-tolerated treatment modality. Seizures, one of the most severe central nervous system side effects of HBO2 therapy, can occur. Episodes of seizures during HBO2 therapy have not yet been reported in countries such as Korea, where hyperbaric medicine is still in the developmental stage. Methods: The registry data of all patients treated with HBO2 therapy in a tertiary academic hospital in Korea were prospectively collected, and patients who developed seizures during HBO2 therapy between October 2016 and December 2019 were evaluated. In addition, we reviewed previous studies on occurrence of seizures during HBO2 therapy. Results: During the study period, a total of 10,425 treatments were provided to 1,308 patients. The most frequently treated indication was carbon monoxide (CO) poisoning ABSTRACT (n=547, 41.8%). During the HBO2 therapy sessions (total: 10,425), five seizure episodes occurred (patients with CO poisoning: n=4; patients with arterial gas embolism [AGE]: n=1). The frequency of seizures in patients with CO poisoning (0.148%) and AGE (3.448%) was significantly higher than that in patients with all indications (0.048%) (p=0.001). None of the patients had lasting effects due to the seizures. Conclusion: Our study revealed a similar frequency rate in terms of all indications and CO poisoning, and a slightly higher rate in AGE. Seizures were observed in patients with CO poisoning and AGE. Therefore, if clinicians plan to operate a hyperbaric center in a country like Korea, where there are several patients with acute CO poisoning, they should be prepared to handle seizures that may occur during HBO2 therapy.

Mitohormesis in Hypothalamic POMC Neurons Mediates Regular Exercise-Induced High-Turnover Metabolism.

Low-grade mitochondrial stress can promote health and longevity, a phenomenon termed mitohormesis. Here, we demonstrate the opposing metabolic effects of low-level and high-level mitochondrial ribosomal (mitoribosomal) stress in hypothalamic proopiomelanocortin (POMC) neurons. POMC neuron-specific severe mitoribosomal stress due to Crif1 homodeficiency causes obesity in mice. By contrast, mild mitoribosomal stress caused by Crif1 heterodeficiency in POMC neurons leads to high-turnover metabolism and resistance to obesity. These metabolic benefits are mediated by enhanced thermogenesis and mitochondrial unfolded protein responses (UPRmt) in distal adipose tissues. In POMC neurons, partial Crif1 deficiency increases the expression of ß-endorphin (ß-END) and mitochondrial DNA-encoded peptide MOTS-c. Central administration of MOTS-c or ß-END recapitulates the adipose phenotype of Crif1 heterodeficient mice, suggesting these factors as potential mediators. Consistently, regular running exercise at moderate intensity stimulates hypothalamic MOTS-c/ß-END expression and induces adipose tissue UPRmt and thermogenesis. Our findings indicate that POMC neuronal mitohormesis may underlie exercise-induced high-turnover metabolism.

Primary cilia mediate early life programming of adiposity through lysosomal regulation in the developing mouse hypothalamus.

Hypothalamic neurons including proopiomelanocortin (POMC)-producing neurons regulate body weights. The non-motile primary cilium is a critical sensory organelle on the cell surface. An association between ciliary defects and obesity has been suggested, but the underlying mechanisms are not fully understood. Here we show that inhibition of ciliogenesis in POMC-expressing developing hypothalamic neurons, by depleting ciliogenic genes IFT88 and KIF3A, leads to adulthood obesity in mice. In contrast, adult-onset ciliary dysgenesis in POMC neurons causes no significant change in adiposity. In developing POMC neurons, abnormal cilia formation disrupts axonal projections through impaired lysosomal protein degradation. Notably, maternal nutrition and postnatal leptin surge have a profound impact on ciliogenesis in the hypothalamus of neonatal mice; through these effects they critically modulate the organization of hypothalamic feeding circuits. Our findings reveal a mechanism of early life programming of adult adiposity, which is mediated by primary cilia in developing hypothalamic neurons.

Cellular Contributors to Hypothalamic Inflammation in Obesity.

The hypothalamus is a crucial organ for the maintenance of appropriate body fat storage. Neurons in the hypothalamic arcuate nucleus (ARH) detect energy shortage or surplus via the circulating concentrations of metabolic hormones and nutrients, and then coordinate energy intake and expenditure to maintain energy homeostasis. Malfunction or loss of hypothalamic ARH neurons results in obesity. Accumulated evidence suggests that hypothalamic inflammation is a key pathological mechanism that links chronic overconsumption of a high-fat diet (HFD) with the development of obesity and related metabolic complications. Interestingly, overnutrition-induced hypothalamic inflammation occurs specifically in the ARH, where microglia initiate an inflammatory response by releasing proinflammatory cytokines and chemokines in response to excessive fatty acid flux. Upon more prolonged HFD consumption, astrocytes and perivascular macrophages become involved and sustain hypothalamic inflammation. ARH neurons are victims of hypothalamic inflammation, but they may actively participate in hypothalamic inflammation by sending quiescence or stress signals to surrounding glia. In this mini-review, we describe the current state of knowledge regarding the contributions of neurons and glia, and their interactions, to HFD-induced hypothalamic inflammation.