Primary cilia regulate adaptive responses to fasting

OBJECTIVE

Neuronal primary cilia are known to be a required organelle for energy balance and leptin action. However, whether primary cilia directly mediate adaptive responses during starvation is yet unknown. Therefore, we investigated the counterregulatory roles of primary cilia, and their related leptin action in energy-depleted condition.

METHOD

We generated leptin receptor (LepR) neuron-specific primary cilia knockout (Ift88 KO^LepR) mice. Leptin-mediated electrophysiological properties of the neurons in fasting condition were assessed using patch-clamp technique. Adaptive responses and neuroendocrine reflexes were measured by monitoring counterregulatory hormones.

RESULTS

In fasting state, the leptin-induced neuronal excitability and leptin homeostasis were impaired in Ift88 KO^LepR. In addition, the Ift88 KO^LepR exhibited aberrant fasting responses including lesser body weight loss, decreased energy expenditure, and lower heat generation compared to wild-type littermates. Furthermore, the primary cilia in LepR neurons are necessary for counterregulatory responses and leptin-mediated neuroendocrine adaptation to starvation.

CONCLUSION

Our results demonstrated that the neuronal primary cilia are crucial neuronal components mediating the adaptive counterregulatory responses to starvation.

Ventromedial hypothalamic primary cilia control energy and skeletal homeostasis

Dysfunction of primary cilia is related to dyshomeostasis, leading to a wide range of disorders. The ventromedial hypothalamus (VMH) is known to regulate several homeostatic processes, but those modulated specifically by VMH primary cilia are not yet known. In this study, we identify VMH primary cilia as an important organelle that maintains energy and skeletal homeostasis by modulating the autonomic nervous system. We established loss-of-function models of primary cilia in the VMH by either targeting IFT88 (IFT88-KOSF-1) using steroidogenic factor 1-Cre (SF-1-Cre) or injecting an adeno-associated virus Cre (AAV-Cre) directly into the VMH. Functional impairments of VMH primary cilia were linked to decreased sympathetic activation and central leptin resistance, which led to marked obesity and bone-density accrual. Obesity was caused by hyperphagia, decreased energy expenditure, and blunted brown fat function and was also associated with insulin and leptin resistance. The effect of bone-density accrual was independent of obesity, as it was caused by decreased sympathetic tone resulting in increased osteoblastic and decreased osteoclastic activities in the IFT88-KOSF-1 and VMH primary cilia knockdown mice. Overall, our current study identifies VMH primary cilia as a critical hypothalamic organelle that maintains energy and skeletal homeostasis.

Search for Sub-eV Sterile Neutrinos at RENO

We report a search result for a light sterile neutrino oscillation with roughly 2200 live days of data in the RENO experiment. The search is performed by electron antineutrino (ν[over ¯]_{e}) disappearance taking place between six 2.8 GW_{th} reactors and two identical detectors located at 294 m (near) and 1383 m (far) from the center of the reactor array. A spectral comparison between near and far detectors can explore reactor ν[over ¯]_{e} oscillations to a light sterile neutrino. An observed spectral difference is found to be consistent with that of the three-flavor oscillation model. This yields limits on sin^{2}2θ_{14} in the 10^{-4}≲|Δm_{41}^{2}|≲0.5  eV^{2} region, free from reactor ν[over ¯]_{e} flux and spectrum uncertainties. The RENO result provides the most stringent limits on sterile neutrino mixing at |Δm_{41}^{2}|≲0.002  eV^{2} using the ν[over ¯]_{e} disappearance channel.

RNF20 Functions as a Transcriptional Coactivator for PPARγ by Promoting NCoR1 Degradation in Adipocytes

Adipose tissue is the key organ coordinating whole-body energy homeostasis. Although it has been reported that ring finger protein 20 (RNF20) regulates lipid metabolism in the liver and kidney, the roles of RNF20 in adipose tissue have not been explored. Here, we demonstrate that RNF20 promotes adipogenesis by potentiating the transcriptional activity of peroxisome proliferator-activated receptor-γ (PPARγ). Under normal chow diet feeding, Rnf20 defective (Rnf20 ^+/- ) mice exhibited reduced fat mass with smaller adipocytes compared with wild-type littermates. In addition, high-fat diet-fed Rnf20 ^+/- mice alleviated systemic insulin resistance accompanied by a reduced expansion of fat tissue. Quantitative proteomic analyses revealed significantly decreased levels of PPARγ target proteins in adipose tissue of Rnf20 ^+/- mice. Mechanistically, RNF20 promoted proteasomal degradation of nuclear corepressor 1 (NCoR1), which led to stimulation of the transcriptional activity of PPARγ. Collectively, these data suggest that RNF20-NCoR1 is a novel axis in adipocyte biology through fine-tuning the transcriptional activity of PPARγ.

Loss of the E3 ubiquitin ligase MKRN1 represses diet-induced metabolic syndrome through AMPK activation

AMP-activated protein kinase (AMPK) plays a key role in controlling energy metabolism in response to physiological and nutritional status. Although AMPK activation has been proposed as a promising molecular target for treating obesity and its related comorbidities, the use of pharmacological AMPK activators has been met with contradictory therapeutic challenges. Here we show a regulatory mechanism for AMPK through its ubiquitination and degradation by the E3 ubiquitin ligase makorin ring finger protein 1 (MKRN1). MKRN1 depletion promotes glucose consumption and suppresses lipid accumulation due to AMPK stabilisation and activation. Accordingly, MKRN1-null mice show chronic AMPK activation in both liver and adipose tissue, resulting in significant suppression of diet-induced metabolic syndrome. We demonstrate also its therapeutic effect by administering shRNA targeting MKRN1 into obese mice that reverses non-alcoholic fatty liver disease. We suggest that ubiquitin-dependent AMPK degradation represents a target therapeutic strategy for metabolic disorders.

AMPK activation has been suggested as treatment for obesity and its complications. Here the authors show that the ubiquitin ligase MKRN1 binds to AMPK and mediates its ubiquitination and degradation. Loss of MKRN1 leads to AMPK activation, increased glucose consumption and decreased lipid accumulation.

Single crystal growth of nanoporous C12A7:e- by controlling melt state

It has been known that electron doped 12CaO x 7Al2O3 (C12A7:e-, electride) single crystals, which are composed of a closed-packed periodic quantum dot structure, may be prepared by strong reduction of the precursor C12A7:O2-, but direct single crystal growth of the C12A7:e- from the melt state has never been achieved to date. We report the melt state of polycrystalline electride in pure dry Ar atmosphere at temperatures of 1290 approximately 1500 degrees C, which leads to the direct single crystal growth of the C12A7:e- from the melt. The electride single crystals with a diameter of 7 mm and a length of 43 mm have been grown by a floating zone method, where a polycrystalline electride feed and an electride single crystal seed rod were employed. The electron concentration in the crystal increased up to approximately 1.0 x 10(20) cm(-3) as the growth proceeded. The present findings suggest that electron-entrapped local structure may exist in the melt and the electrons may act as a template for the formation of C12A7 electride in the solidification process of the C12A7 lattice.

Luminescence tuning of amorphous Si quantum dots prepared by plasma-enhanced chemical vapor deposition

Amorphous Si (a-Si) quantum dots (QDs) embedded in a silicon nitride film were prepared by a plasma-enhanced chemical vapor deposition (PECVD) technique using gaseous mixtures of silane, hydrogen and nitrogen. We observed that the Si QDs had an amorphous structure from the Raman spectroscopy measurement. The Fourier transform infrared (FTIR) spectra showed that the relative transmittance of the SiH bands decreased, but that of the NH bands increased, with increasing nitrogen flow rate. During the deposition of SiNx, the number of dangling bonds of silicon acting as nucleation sites increased. As the hydrogen flow rate increased the growth rate decreased, due to the reduction in the hydrogen partial pressure. The hydrogen and nitrogen gas flow rates were found to be important parameters for determining the size of the a-Si QDs. In addition, we observed that the PL peak shifted toward a higher energy with increasing hydrogen and nitrogen gas flow rates, which was attributed to the increase in the quantum confinement effect in the a-Si QDs.

A case of coagulation factor V deficiency complicated with intracranial hemorrhage

Factor V deficiency is a relatively uncommon disorder, inherited as an autosomal recessive trait that manifests clinically only in individuals who inherit the defective gene from both parents. The hemorrhage of nasal and oral cavity and ecchymosis are common but intracranial hemorrhage is very rare. We experienced a 53 year old male patient with intracranial hemorrhage due to factor V deficiency. The laboratory tests showed prolongation of APTT and PT, normal bleeding time and normal thrombin time. The levels of the coagulation profiles on the patient revealed a significant decrease factor V, below 1% of normal range (60-140%). Other coagulation factors were normal. He was treated with fresh frozen plasma and completely recovered 3 weeks after treatment.

Characterization and electrical properties of chemical vapor deposited ferroelectric lead titanate films on titanium

Lead titanate thin films were deposited on titanium substrates by a chemical vapor deposition (CVD) process involving the application of vapor mixtures of Pb, ethyl titanate (Ti(C(2)H(5)O) (4)), and oxygen. Auger electron spectroscopy (AES) analyses were performed to determine the chemical composition of lead titanate films. AES analysis revealed that TiO(2) and TiO interlayers formed between the PbTiO(3) and titanium substrate. AES also showed that stoichiometry was obtained in the lead titanate film deposited at 750 degrees C, Ti(C(2)H(2)O)(4) with 0.152, an O(2) partial pressure of 0.06 atm, and a gas flow rate of 800 sccm. The lead titanate with a stoichiometric composition has a DC conductivity of 3.2x10(-12) Omega(-1)-cm(-1) at room temperature. The nonsaturating loops observed in the present investigation may be caused by TiO(2) and TiO layers between the conductive substrate and the PbTiO(3) ferroelectric film. The ferroelectric properties of the stoichiometric PbTiO(3) film included a remanent polarization of 14.1 muC/cm(3) and a coercive field of 20.16 kV/cm.