Rho-Kinase Is Differentially Expressed in the Adipose Tissue of Rodent and Human in Response to Aging, Sex, and Acute Exercise.

White adipose tissue (WAT) controls energy storage, expenditure, and endocrine function. Rho-kinase (ROCK) is related to impaired thermogenesis, downregulation of preadipocyte differentiation, and adipokine production. Furthermore, WAT ROCK responds to metabolic stress from high-fat diets or diabetes. However, ROCK distribution in adipose depots and its response to aging and sex remain unclear. Thus, we aim to investigate ROCK function in adipose tissue of rodent and human in response to aging and sex. We observed specific differences in the ROCK1/2 distribution in inguinal WAT (ingWAT), perigonadal WAT (pgWAT), and brown adipose tissue of male and female rodents. However, ROCK2 expression was lower in female ingWAT compared with males, a fact that was not observed in the other depots. In the pgWAT and ingWAT of male and female rodents, ROCK activity increased during development. Moreover, middle-aged female rodents and humans showed downregulation in ROCK activity after acute physical exercise. Interestingly, ROCK levels were associated with several inflammatory markers both in rats and humans WAT (Nfkb1, Tnf, Il1b, Il6, and Mcp1). Induction of cell senescence by etoposide elevates ROCK activity in human preadipocytes; however, silencing ROCK1/2 demonstrates improvement in the inflammatory and cell senescence state. Using public databases, several pathways were strongly associated with ROCK modulation in WAT. In summary, WAT ROCK increases with development in association with inflammatory markers. Further, ROCK activity was attenuated by acute physical exercise, implicating it as a possible therapeutic target for metabolism improvement mediated by adipose tissue inflammatory state changes.

Physical exercise elicits UPRmt in the skeletal muscle: The role of c-Jun N-terminal kinase.

OBJECTIVE: The mitochondrial unfolded protein response (UPRmt) is an adaptive cellular response to stress to ensure mitochondrial proteostasis and function. Here we explore the capacity of physical exercise to induce UPRmt in the skeletal muscle. METHODS: Therefore, we combined mouse models of exercise (swimming and treadmill running), pharmacological intervention, and bioinformatics analyses. RESULTS: Firstly, RNA sequencing and Western blotting analysis revealed that an acute aerobic session stimulated several mitostress-related genes and protein content in muscle, including the UPRmt markers. Conversely, using a large panel of isogenic strains of BXD mice, we identified that BXD73a and 73b strains displayed low levels of several UPRmt-related genes in the skeletal muscle, and this genotypic feature was accompanied by body weight gain, lower locomotor activity, and aerobic capacity. Finally, we identified that c-Jun N-terminal kinase (JNK) activation was critical in exercise-induced UPRmt in the skeletal muscle since pharmacological JNK pathway inhibition blunted exercise-induced UPRmt markers in mice muscle. CONCLUSION: Our findings provide new insights into how exercise triggers mitostress signals toward the oxidative capacity in the skeletal muscle.

Evidence for a neuromuscular circuit involving hypothalamic interleukin-6 in the control of skeletal muscle metabolism.

Hypothalamic interleukin-6 (IL6) exerts a broad metabolic control. Here, we demonstrated that IL6 activates the ERK1/2 pathway in the ventromedial hypothalamus (VMH), stimulating AMPK/ACC signaling and fatty acid oxidation in mouse skeletal muscle. Bioinformatics analysis revealed that the hypothalamic IL6/ERK1/2 axis is closely associated with fatty acid oxidation- and mitochondrial-related genes in the skeletal muscle of isogenic BXD mouse strains and humans. We showed that the hypothalamic IL6/ERK1/2 pathway requires the α2-adrenergic pathway to modify fatty acid skeletal muscle metabolism. To address the physiological relevance of these findings, we demonstrated that this neuromuscular circuit is required to underpin AMPK/ACC signaling activation and fatty acid oxidation after exercise. Last, the selective down-regulation of IL6 receptor in VMH abolished the effects of exercise to sustain AMPK and ACC phosphorylation and fatty acid oxidation in the muscle after exercise. Together, these data demonstrated that the IL6/ERK axis in VMH controls fatty acid metabolism in the skeletal muscle.

High-intensity exercise training induces mitonuclear imbalance and activates the mitochondrial unfolded protein response in the skeletal muscle of aged mice.

The impairment of mitochondrial metabolism is a hallmark of aging. Mitonuclear imbalance and the mitochondrial unfolded protein response (UPRmt) are two conserved mitochondrial mechanisms that play critical roles in ensuring mitochondrial proteostasis and function. Here, we combined bioinformatics, physiological, and molecular analyses to examine the role of mitonuclear imbalance and UPRmt in the skeletal muscle of aged rodents and humans. The analysis of transcripts from the skeletal muscle of aged humans (60-70 years old) revealed that individuals with higher levels of UPRmt-related genes displayed a consistent increase in several mitochondrial-related genes, including the OXPHOS-associated genes. Interestingly, high-intensity interval training (HIIT) was effective in stimulating the mitonuclear imbalance and UPRmt in the skeletal muscle of aged mice. Furthermore, these results were accompanied by higher levels of several mitochondrial markers and improvements in physiological parameters and physical performance. These data indicate that the maintenance or stimulation of the mitonuclear imbalance and UPRmt in the skeletal muscle could ensure mitochondrial proteostasis during aging, revealing new insights into targeting mitochondrial metabolism by using physical exercise.

iNOS promotes hypothalamic insulin resistance associated with deregulation of energy balance and obesity in rodents.

Inducible nitric oxide (iNOS)-mediated S-nitrosation of the metabolic signaling pathway has emerged as a post-translational modification that triggers insulin resistance in obesity and aging. However, the effects of S-nitrosation in controlling energy homeostasis are unknown. Thus, in the present study we aimed to evaluate the effects of S-nitrosation in insulin signaling pathway in the hypothalamus of rodents. Herein, we demonstrated that the intracerebroventricular infusion of the nitric oxide (NO) donor S-nitrosoglutathione (GSNO) promoted hypothalamic insulin signaling resistance and replicated the food intake pattern of obese individuals. Indeed, obesity induced S-nitrosation of hypothalamic IR and Akt, whereas inhibition of iNOS or S-nitrosation of insulin signaling pathway protected against hypothalamic insulin resistance and normalized energy homeostasis. Overall, these findings indicated that S-nitrosation of insulin signaling pathway is required to sustain hypothalamic insulin resistance in obesity.

Hypothalamic S1P/S1PR1 axis controls energy homeostasis in Middle-Aged Rodents: the reversal effects of physical exercise.

Recently, we demonstrated that the hypothalamic S1PR1/STAT3 axis plays a critical role in the control of food consumption and energy expenditure in rodents. Here, we found that reduction of hypothalamic S1PR1 expression occurs in an age-dependent manner, and was associated with defective thermogenic signaling and weight gain. To address the physiological relevance of these findings, we investigated the effects of chronic and acute exercise on the hypothalamic S1PR1/STAT3 axis. Chronic exercise increased S1PR1 expression and STAT3 phosphorylation in the hypothalamus, restoring the anorexigenic and thermogenic signals in middle-aged mice. Acutely, exercise increased sphingosine-1-phosphate (S1P) levels in the cerebrospinal fluid (CSF) of young rats, whereas the administration of CSF from exercised young rats into the hypothalamus of middle-aged rats at rest was sufficient to reduce the food intake. Finally, the intracerebroventricular (ICV) administration of S1PR1 activators, including the bioactive lipid molecule S1P, and pharmacological S1PR1 activator, SEW2871, induced a potent STAT3 phosphorylation and anorexigenic response in middle-aged rats. Overall, these results suggest that hypothalamic S1PR1 is important for the maintenance of energy balance and provide new insights into the mechanism by which exercise controls the anorexigenic and thermogenic signals in the central nervous system during the aging process.

Exercise training decreases mitogen-activated protein kinase phosphatase-3 expression and suppresses hepatic gluconeogenesis in obese mice.

Insulin plays an important role in the control of hepatic glucose production. Insulin resistant states are commonly associated with excessive hepatic glucose production, which contributes to both fasting hyperglycaemia and exaggerated postprandial hyperglycaemia. In this regard, increased activity of phosphatases may contribute to the dysregulation of gluconeogenesis. Mitogen-activated protein kinase phosphatase-3 (MKP-3) is a key protein involved in the control of gluconeogenesis. MKP-3-mediated dephosphorylation activates FoxO1 (a member of the forkhead family of transcription factors) and subsequently promotes its nuclear translocation and binding to the promoters of gluconeogenic genes such as phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase). In this study, we investigated the effects of exercise training on the expression of MKP-3 and its interaction with FoxO1 in the livers of obese animals. We found that exercised obese mice had a lower expression of MKP-3 and FoxO1/MKP-3 association in the liver. Further, the exercise training decreased FoxO1 phosphorylation and protein levels of Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) and gluconeogenic enzymes (PEPCK and G6Pase). These molecular results were accompanied by physiological changes, including increased insulin sensitivity and reduced hyperglycaemia, which were not caused by reductions in total body mass. Similar results were also observed with oligonucleotide antisense (ASO) treatment. However, our results showed that only exercise training could reduce an obesity-induced increase in HNF-4α protein levels while ASO treatment alone had no effect. These findings could explain, at least in part, why additive effects of exercise training treatment and ASO treatment were not observed. Finally, the suppressive effects of exercise training on MKP-3 protein levels appear to be related, at least in part, to the reduced phosphorylation of Extracellular signal-regulated kinases (ERK) in the livers of obese mice.

Analysis of the physical activity effects and measurement of pro-inflammatory cytokines in irradiated lungs in rats.

PURPOSE: To study if the pre-radiotherapy physical activity has radio-protective elements, by measuring the radio-induced activation of pro-inflammatory cytokines as interleukin-6 (il-6), transforming growth factor -ß (tgf -ß), tumor necrosis factor -α (tnf-α) and protein beta kinase ß (ikkß), through western blotting analysis. METHODS: A randomized study with 28 Wistar hannover rats, males, with a mean age of 90 days and weighing about 200 grams. The animals were divided into three groups: (GI, GII and GIII). GIII group were submitted to swimming for eight weeks (zero load, three times a week, about 30 minutes). Then, the groups (except the control group) were submitted to irradiation by cobalt therapy, single dose of 3.5 gray in the whole body. All animals were sacrificed by overdose of pentobarbital, according to the time for analysis of cytokines, and then a fragment of the lower lobe of the right lung went to western blotting analysis. RESULTS: The cytokines IKK ß, TNF-α and IL-6 induced by radiation in the lung were lower in the exercised animals. However, exercise did not alter the radiation-induced increase in tgf-ß. CONCLUSION: The results show a lower response in relation to inflammatory cytokines in the group that practiced the exercise pre-radiotherapy, showing that exercise can protect tissues from tissue damage due to irradiation.

Analysis of the physical activity effects and measurement of pro-inflammatory cytokines in irradiated lungs in rats / Análise dos efeitos da atividade física e mensuração de citocinas pró-inflamatórias em pulmões irradiados em ratos

PURPOSE: To study if the pre-radiotherapy physical activity has radio-protective elements, by measuring the radio-induced activation of pro-inflammatory cytokines as interleukin-6 (il-6), transforming growth factor -β (tgf -β), tumor necrosis factor -α (tnf-α) and protein beta kinase β (ikkβ), through western blotting analysis. METHODS: A randomized study with 28 Wistar hannover rats, males, with a mean age of 90 days and weighing about 200 grams. The animals were divided into three groups: (GI, GII and GIII). GIII group were submitted to swimming for eight weeks (zero load, three times a week, about 30 minutes). Then, the groups (except the control group) were submitted to irradiation by cobalt therapy, single dose of 3.5 gray in the whole body. All animals were sacrificed by overdose of pentobarbital, according to the time for analysis of cytokines, and then a fragment of the lower lobe of the right lung went to western blotting analysis. RESULTS: The cytokines IKK β, TNF-α and IL-6 induced by radiation in the lung were lower in the exercised animals. However, exercise did not alter the radiation-induced increase in tgf-β. CONCLUSION: The results show a lower response in relation to inflammatory cytokines in the group that practiced the exercise pre-radiotherapy, showing that exercise can protect tissues from tissue damage due to irradiation.

OBJETIVO: Verificar se a radioterapia pré-atividade física tem elementos de rádio-proteção, medindo-se a ativação de citocinas pró-inflamatórias como a interleucina-6 (IL-6), fator transformador de crescimento - β (TGF - β), fator de necrose tumoral - α (TNF-α) e quinase de proteína beta β (IKK β), por meio da análise blotting ocidental. MÉTODOS: Um estudo randomizado empregando 28 ratos Wistar Hannover, machos, com idade média de 90 dias e pesando cerca de 200 gramas. Os animais foram divididos em três grupos: (GI, GII e GIII). Os animais do grupo GIII foram submetidos à natação durante oito semanas (carga zero, três vezes por semana, cerca de 30 minutos). Então, os grupos (exceto o grupo controle) foram submetidos à irradiação por cobalto terapia, dose única de 3,5 cinza em todo o corpo. Todos os animais foram sacrificados por overdose de pentobarbital, de acordo com o tempo de análise de citocinas, em seguida, um fragmento do lobo inferior do pulmão direito foi a análise de mata-borrão ocidental. RESULTADOS: As citocinas IKK β, TNF-α e IL-6 induzidas por radiação no pulmão foram menores nos animais que se exercitaram. No entanto, o exercício não alterou o aumento induzido pela radiação na TGF-β. CONCLUSÃO: Os resultados mostraram uma menor resposta em relação às citocinas inflamatórias no grupo que praticou o exercício físico pré-radioterapia, evidenciando que o exercício pode proteger os tecidos das lesões teciduais decorrentes da irradiação.