Biology subjects

Iwakoshi-Ukena, E.

Publications and source records attributed to Iwakoshi-Ukena, E..

5 recordsLinked to original sources

bioRxiv2021

Neurosecretory protein GL-induced fat accumulation is accompanied by repressing the immune-inflammatory response in the adipose tissue of mice

We have recently identified neurosecretory protein GL (NPGL), a small secretory protein expressed in the vertebrate hypothalamus, as an orexigenic factor with remarkable fat accumulation by overexpression of the NPGL precursor gene (Npgl) for two months. In the present study, we analyzed the effects of short-term Npgl overexpression for 18 days as the early stage of obesity to address the mechanisms underlying obese-like phenotype. Similar to previous studies, short-term Npgl overexpression stimulated food intake and fat accumulation in the white adipose tissues (WAT), whereas the masses of the brown adipose tissue, testis, liver, heart, and muscle remained unchanged. In addition, we observed increased blood insulin and leptin levels due to Npgl overexpression, while little changes were induced in blood glucose, free fatty acids, triglyceride, and cholesterol levels. Furthermore, transcriptome analysis of the inguinal WAT using RNA-sequencing technique revealed that overexpression of Npgl upregulated the genes involved in cytoskeleton regulation, whereas it decreased those involved in immune-inflammatory responses. These results suggest that NPGL plays a crucial role in enlarging adipocytes and suppressing inflammation to avoid metabolic abnormalities, eventually contributing to accelerating energy storage.

physiology↗

bioRxiv2021

A Novel Hypothalamic Factor, Neurosecretory Protein GM, Causes Fat Deposition in Chicks

We recently discovered a novel cDNA encoding the precursor of a small secretory protein, neurosecretory protein GM (NPGM), in the mediobasal hypothalamus of chickens. Although our previous study showed that subcutaneous infusion of NPGM for 6 days increased body mass in chicks, the chronic effect of intracerebroventricular (i.c.v.) infusion of NPGM remains unknown. In this study, chronic i.c.v. infusion of NPGM for 2 weeks significantly increased body mass, water intake, and the mass of abdominal fat in chicks, whereas NPGM did not affect food intake, muscle mass, or blood glucose concentration. Morphological analyses revealed that fat accumulation occurred in both liver and abdominal fat. These results indicate that NPGM may participate in fat storage in chicks.

physiology↗

bioRxiv2021

Overexpression of the gene encoding neurosecretory protein GL precursor prevents excessive fat accumulation in the adipose tissue of mice fed a long-term high-fat diet

We previously identified a novel small hypothalamic protein, neurosecretory protein GL (NPGL), which induces feeding behavior and fat accumulation in rodents depending on their diet. In the present study, we explored the effects of NPGL on feeding behavior and energy metabolism in mice placed on a long-term high-fat diet with 60% calories from fat (HFD 60). Overexpression of the NPGL precursor gene (Npgl) over 18 weeks increased food intake and body mass. The weekly body mass gain of Npgl-overexpressing mice was higher than that of controls until 7 weeks from induction of overexpression, after which it ceased to be so. Oral glucose tolerance tests showed that Npgl overexpression maintained glucose tolerance and increased blood insulin levels, and intraperitoneal insulin tolerance tests showed that it maintained insulin sensitivity. At the experimental endpoint, Npgl overexpression was associated with increased mass of the perirenal white adipose tissue (WAT) and decreased mass of the epididymal WAT (eWAT), resulting in little effect on the total WAT mass. These results suggest that under long-term HFD 60 feeding, Npgl overexpression may play a role in avoiding metabolic disturbance both by accelerating energy storage and by suppressing excess fat accumulation in certain tissues, such as the eWAT.

physiology↗

bioRxiv2021

Subcutaneous infusion of neurosecretory protein GL promotes fat accumulation in mice

We recently identified a novel small secretory protein, neurosecretory protein GL (NPGL), in the vertebrate hypothalamus. We revealed that NPGL is involved in energy homeostasis using intracerebroventricular infusion in rodents. However, the effect of NPGL through peripheral administration remains to be elucidated and may be important for therapeutic use. In this study, we performed subcutaneous infusion of NPGL in mice for 12 days and found that it accelerated fat accumulation in white adipose tissue (WAT) without increasing in body mass gain and food intake. The mass of the testis, liver, kidney, heart, and gastrocnemius muscle remained unchanged. Analysis of mRNA expression by quantitative reverse transcription-polymerase chain reaction showed that proopiomelanocortin was suppressed in the hypothalamus by the infusion of NPGL. We observed a decreasing tendency in serum triglyceride levels due to NPGL, while serum glucose, insulin, leptin, and free fatty acids levels were unchanged. These results suggest that the peripheral administration of NPGL induces fat accumulation in WAT via the hypothalamus.

physiology↗

bioRxiv2021

Hypothalamic Overexpression of Neurosecretory Protein GL Leads to Obesity in Mice

IntroductionThe mechanisms underlying obesity are not fully understood, necessitating the creation of novel animal models for investigation of metabolic disorders from the cellular-molecular to behavioral levels of analysis. We have previously found that neurosecretory protein GL (NPGL), a newly-identified hypothalamic neuropeptide, is involved in feeding behavior and fat accumulation in rats. Given the broad availability of genetic tools in mice, the present investigation sought to establish a mouse model of NPGL-induced obesity. MethodsWe overexpressed the NPGL-precursor gene (Npgl) in the hypothalamus using adeno-associated virus in C57BL/6J mice fed normal chow (NC) or a high-calorie diet (HCD). After 9 weeks of Npgl overexpression, we measured adipose tissues, muscle, and several organ masses in addition to food intake and body mass. To assess the effects of Npgl overexpression on peripheral tissues, we analyzed mRNA expression of lipid metabolism-related genes by quantitative RT-PCR. ResultsNpgl overexpression increased food intake, body mass, adipose tissues and liver masses, food efficiency, and circulating insulin levels under both NC and HCD, resulting in obesity observable within 8 weeks. Furthermore, we observed fat accumulation in adipose tissues and liver. Additionally, mRNA expression of lipid metabolism-related factors was increased in white adipose tissue and the liver after Npgl overexpression. ConclusionTaken together, the present study suggests that NPGL is an endogenous obesogenic factor that acts within a short period of time in mice. As a result, this animal model can be widely applied to study the etiology of obesity from genes to behavior.

neuroscience↗