Top read articles in the last 30 days
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Abstract
Diabetes mellitus is associated with various disorders of the locomotor system including the decline in mass and function of skeletal muscle. The mechanism underlying this association has remained ambiguous, however. We now show that the abundance of the transcription factor KLF15 as well as the expression of genes related to muscle atrophy are increased in skeletal muscle of diabetic model mice, and that mice with muscle-specific KLF15 deficiency are protected from the diabetes-induced decline of skeletal muscle mass. Hyperglycemia was found to upregulate the KLF15 protein in skeletal muscle of diabetic animals, which is achieved via downregulation of the E3 ubiquitin ligase WWP1 and consequent suppression of the ubiquitin-dependent degradation of KLF15. Our results revealed that hyperglycemia, a central disorder in diabetes, promotes muscle atrophy via a WWP1/KLF15 pathway. This pathway may serve as a therapeutic target for decline in skeletal muscle mass accompanied by diabetes mellitus.
Authors
Yu Hirata, Kazuhiro Nomura, Yoko Senga, Yuko Okada, Kenta Kobayashi, Shiki Okamoto, Yasuhiko Minokoshi, Michihiro Imamura, Shin’ichi Takeda, Tetsuya Hosooka, Wataru Ogawa
Total views: 3906
Abstract
The lack of intrinsic motivation to engage in, and adhere to, physical exercise has major health consequences. However, the neurobiological bases of exercise motivation are still unknown. This study aimed at examining whether the endocannabinoid system (ECS) is involved in this process. To do so, we developed an operant conditioning paradigm wherein mice unlocked a running wheel with nose pokes. Using pharmacological tools and conditional mutants for cannabinoid type-1 (CB1) receptors, we provide evidence that CB1 receptors located on GABAergic neurons are both necessary and sufficient to positively control running motivation. Conversely, this receptor population proved dispensable for the modulation of running duration per rewarded sequence. Although the ECS mediated the motivation for another reward, namely palatable food, such a regulation was independent from CB1 receptors on GABAergic neurons. In addition, we report that the lack of CB1 receptors on GABAergic neurons decreases the preference for running over palatable food when mice were proposed an exclusive choice between the two rewards. Beyond providing a paradigm that enables motivation processes for exercise to be dissected either singly or in concurrence, this study is the first to our knowledge to identify a neurobiological mechanism that might contribute to sedentary behavior.
Authors
Carolina Muguruza, Bastien Redon, Giulia R. Fois, Imane Hurel, Amandine Scocard, Claire Nguyen, Christopher Stevens, Edgar Soria-Gomez, Marjorie Varilh, Astrid Cannich, Justine Daniault, Arnau Busquets-Garcia, Teresa Pelliccia, Stéphanie Caillé, François Georges, Giovanni Marsicano, Francis Chaouloff
Total views: 2006
Abstract
BACKGROUND. Topical calcipotriol plus 5-fluorouracil (5-FU) combination is an effective immunotherapy against actinic keratosis (AK), which is a precursor to squamous cell carcinoma (SCC). However, the long-term effectiveness of calcipotriol plus 5-FU treatment for SCC prevention is unknown. METHODS. We performed a blinded prospective cohort study on participants of a randomized double-blind clinical trial in which a 4-day course of topical calcipotriol plus 5-FU combination was compared to Vaseline plus 5-FU (control) for AK treatment. SCC and basal cell carcinoma (BCC) incidences were assessed at 1, 2, and 3 years after trial. Tissues were analyzed for calcipotriol plus 5-FU–induced T cell immunity in the skin. RESULTS. Calcipotriol plus 5-FU–induced tissue-resident memory T (Trm) cell formation in face and scalp skin associated with significantly higher erythema scores compared with control (P < 0.01). Importantly, more participants in the test cohort remained SCC-free over the more than 1,500-day follow-up period (P = 0.0765), and significantly fewer developed SCC on the treated face and scalp within 3 years (2 of 30 [7%] versus 11 of 40 [28%] in control group, hazard ratio 0.215 [95% CI: 0.048–0.972], P = 0.032). Accordingly, significantly more epidermal Trm cells persisted in the calcipotriol plus 5-FU–treated face and scalp skin compared with control (P = 0.0028). There was no significant difference in BCC incidence between the treatment groups. CONCLUSION. A short course of calcipotriol plus 5-FU treatment on the face and scalp is associated with induction of robust T cell immunity and Trm formation against AKs and significantly lowers the risk of SCC development within 3 years of treatment. FUNDING. This research was supported by internal academic funds and by grants from the Burroughs Wellcome Fund, Sidney Kimmel Foundation, Cancer Research Institute, and NIH.
Authors
Abby R. Rosenberg, Mary Tabacchi, Kenneth H. Ngo, Michael Wallendorf, Ilana S. Rosman, Lynn A. Cornelius, Shadmehr Demehri
Total views: 1612
Abstract
BACKGROUND. Cannabidiol (CBD) is a nonpsychoactive phytocannabinoid used in multiple sclerosis and intractable epilepsies. Preclinical studies show CBD has numerous cardiovascular benefits, including a reduced blood pressure (BP) response to stress. The aim of this study was to investigate if CBD reduces BP in humans. METHODS. Nine healthy male volunteers were given 600 mg of CBD or placebo in a randomized, placebo-controlled, double-blind, crossover study. Cardiovascular parameters were monitored using a finometer and laser Doppler. RESULTS. CBD reduced resting systolic BP (–6 mmHg; P < 0.05) and stroke volume (–8 ml; P < 0.05), with increased heart rate (HR) and maintained cardiac output. Subjects who had taken CBD had lower BP (–5 mmHg; P < 0.05, especially before and after stress), increased HR (+10 bpm; P < 0.01), decreased stroke volume (–13 ml; P < 0.01), and a blunted forearm skin blood flow response to isometric exercise. In response to cold stress, subjects who had taken CBD had blunted BP (–6 mmHg; P < 0.01) and increased HR (+7 bpm; P < 0.05), with lower total peripheral resistance. CONCLUSIONS. This data shows that acute administration of CBD reduces resting BP and the BP increase to stress in humans, associated with increased HR. These hemodynamic changes should be considered for people taking CBD. Further research is required to establish whether CBD has a role in the treatment of cardiovascular disorders.
Authors
Khalid A. Jadoon, Garry D. Tan, Saoirse E. O’Sullivan
Total views: 1365
Abstract
Pharmacologic inhibition of the renal sodium/glucose cotransporter-2 induces glycosuria and reduces glycemia. Given that SGLT2 inhibitors (SGLT2i) reduce mortality and cardiovascular risk in type 2 diabetes, improved understanding of molecular mechanisms mediating these metabolic effects is required. Treatment of obese but nondiabetic mice with the SGLT2i canagliflozin (CANA) reduces adiposity, improves glucose tolerance despite reduced plasma insulin, increases plasma ketones, and improves plasma lipid profiles. Utilizing an integrated transcriptomic-metabolomics approach, we demonstrate that CANA modulates key nutrient-sensing pathways, with activation of 5′ AMP-activated protein kinase (AMPK) and inhibition of mechanistic target of rapamycin (mTOR), independent of insulin or glucagon sensitivity or signaling. Moreover, CANA induces transcriptional reprogramming to activate catabolic pathways, increase fatty acid oxidation, reduce hepatic steatosis and diacylglycerol content, and increase hepatic and plasma levels of FGF21. Given that these phenotypes mirror the effects of FGF21 to promote lipid oxidation, ketogenesis, and reduction in adiposity, we hypothesized that FGF21 is required for CANA action. Using FGF21-null mice, we demonstrate that FGF21 is not required for SGLT2i-mediated induction of lipid oxidation and ketogenesis but is required for reduction in fat mass and activation of lipolysis. Taken together, these data demonstrate that SGLT2 inhibition triggers a fasting-like transcriptional and metabolic paradigm but requires FGF21 for reduction in adiposity.
Authors
Soravis Osataphan, Chiara Macchi, Garima Singhal, Jeremy Chimene-Weiss, Vicencia Sales, Chisayo Kozuka, Jonathan M. Dreyfuss, Hui Pan, Yanin Tangcharoenpaisan, Jordan Morningstar, Robert Gerszten, Mary-Elizabeth Patti
Total views: 1247
Abstract
Evidence has emerged that the failing heart increases utilization of ketone bodies. We sought to determine whether this fuel shift is adaptive. Mice rendered incapable of oxidizing the ketone body 3-hydroxybutyrate (3OHB) in the heart exhibited worsened heart failure in response to fasting or a pressure overload/ischemic insult compared with WT controls. Increased delivery of 3OHB ameliorated pathologic cardiac remodeling and dysfunction in mice and in a canine pacing model of progressive heart failure. 3OHB was shown to enhance bioenergetic thermodynamics of isolated mitochondria in the context of limiting levels of fatty acids. These results indicate that the heart utilizes 3OHB as a metabolic stress defense and suggest that strategies aimed at increasing ketone delivery to the heart could prove useful in the treatment of heart failure.
Authors
Julie L. Horton, Michael T. Davidson, Clara Kurishima, Rick B. Vega, Jeffery C. Powers, Timothy R. Matsuura, Christopher Petucci, E. Douglas Lewandowski, Peter A. Crawford, Deborah M. Muoio, Fabio A. Recchia, Daniel P. Kelly
Total views: 1121
Abstract
Atherosclerosis is a leading cause of death worldwide in industrialized countries. Disease progression and regression are associated with different activation states of macrophages derived from inflammatory monocytes entering the plaques. The features of monocyte-to-macrophage transition and the full spectrum of macrophage activation states during either plaque progression or regression, however, are incompletely established. Here, we use a combination of single-cell RNA sequencing and genetic fate mapping to profile, for the first time to our knowledge, plaque cells derived from CX3CR1+ precursors in mice during both progression and regression of atherosclerosis. The analyses revealed a spectrum of macrophage activation states with greater complexity than the traditional M1 and M2 polarization states, with progression associated with differentiation of CXC3R1+ monocytes into more distinct states than during regression. We also identified an unexpected cluster of proliferating monocytes with a stem cell–like signature, suggesting that monocytes may persist in a proliferating self-renewal state in inflamed tissue, rather than differentiating immediately into macrophages after entering the tissue.
Authors
Jian-Da Lin, Hitoo Nishi, Jordan Poles, Xiang Niu, Caroline Mccauley, Karishma Rahman, Emily J. Brown, Stephen T. Yeung, Nikollaq Vozhilla, Ada Weinstock, Stephen A. Ramsey, Edward A. Fisher, P’ng Loke
Total views: 1093
Abstract
Genomic studies revealed the existence of health- and acne-associated P. acnes strains and suggested novel approaches for broadening understanding of acne vulgaris. However, clinical association of P. acnes with disease or health has yet to be corroborated experimentally. Current animal models of acne do not closely mimic human disease and have unclear translational value. We have developed a murine model of acne by combining P. acnes inoculation with topical application of a synthetic human sebum. We showed that human sebum promoted persistence of intradermally injected P. acnes with little loss of viability after 1 week and permitted use of more physiologic inoculums. Application of acne-associated P. acnes RT4/5 strains led to development of moderate to severe skin pathology compared with application of health-associated type II P. acnes strains (RT2/6). RT4/5 P. acnes strains uniformly induced higher levels of KC (IL-8), IL-1α, IL-1β, and IL-6 in vitro and in vivo compared with type II P. acnes strains. Overall, our data provide immunopathologic corroboration of health and disease association of clinical P. acnes strains and inform on a platform to query putative virulence factors uncovered by genomic studies.
Authors
Stacey L. Kolar, Chih-Ming Tsai, Juan Torres, Xuemo Fan, Huiying Li, George Y. Liu
Total views: 1027
Abstract
BACKGROUND. Common variable immunodeficiency (CVID) is the most common symptomatic primary immunodeficiency and is frequently complicated by interstitial lung disease (ILD) for which etiology is unknown and therapy inadequate. METHODS. Medical record review implicated B cell dysregulation in CVID ILD progression. This was further studied in blood and lung samples using culture, cytometry, ELISA, and histology. Eleven CVID ILD patients were treated with rituximab and followed for 18 months. RESULTS. Serum IgM increased in conjunction with ILD progression, a finding that reflected the extent of IgM production within B cell follicles in lung parenchyma. Targeting these pulmonary B cell follicles with rituximab ameliorated CVID ILD, but disease recurred in association with IgM elevation. Searching for a stimulus of this pulmonary B cell hyperplasia, we found B cell–activating factor (BAFF) increased in blood and lungs of progressive and post-rituximab CVID ILD patients and detected elevation of BAFF-producing monocytes in progressive ILD. This elevated BAFF interacts with naive B cells, as they are the predominant subset in progressive CVID ILD, expressing BAFF receptor (BAFF-R) within pulmonary B cell follicles and blood to promote Bcl-2 expression. Antiapoptotic Bcl-2 was linked with exclusion of apoptosis from B cell follicles in CVID ILD and increased survival of naive CVID B cells cultured with BAFF. CONCLUSION. CVID ILD is driven by pulmonary B cell hyperplasia that is reflected by serum IgM elevation, ameliorated by rituximab, and bolstered by elevated BAFF-mediated apoptosis resistance via BAFF-R. FUNDING. NIH, Primary Immune Deficiency Treatment Consortium, and Rare Disease Foundation.
Authors
Paul J. Maglione, Gavin Gyimesi, Montserrat Cols, Lin Radigan, Huaibin M. Ko, Tamar Weinberger, Brian H. Lee, Emilie K. Grasset, Adeeb H. Rahman, Andrea Cerutti, Charlotte Cunningham-Rundles
Total views: 995
Abstract
Idiopathic intracranial hypertension (IIH) is a condition of unknown etiology, characterized by elevated intracranial pressure frequently manifesting with chronic headaches and visual loss. Similar to polycystic ovary syndrome (PCOS), IIH predominantly affects obese women of reproductive age. In this study, we comprehensively examined the systemic and cerebrospinal fluid (CSF) androgen metabolome in women with IIH in comparison with sex-, BMI-, and age-matched control groups with either simple obesity or PCOS (i.e., obesity and androgen excess). Women with IIH showed a pattern of androgen excess distinct to that observed in PCOS and simple obesity, with increased serum testosterone and increased CSF testosterone and androstenedione. Human choroid plexus expressed the androgen receptor, alongside the androgen-activating enzyme aldoketoreductase type 1C3. We show that in a rat choroid plexus cell line, testosterone significantly enhanced the activity of Na+/K+-ATPase, a surrogate of CSF secretion. We demonstrate that IIH patients have a unique signature of androgen excess and provide evidence that androgens can modulate CSF secretion via the choroid plexus. These findings implicate androgen excess as a potential causal driver and therapeutic target in IIH.
Authors
Michael W. O’Reilly, Connar S.J. Westgate, Catherine Hornby, Hannah Botfield, Angela E. Taylor, Keira Markey, James L. Mitchell, William J. Scotton, Susan P. Mollan, Andreas Yiangou, Carl Jenkinson, Lorna C. Gilligan, Mark Sherlock, James Gibney, Jeremy W. Tomlinson, Gareth G. Lavery, David J. Hodson, Wiebke Arlt, Alexandra J. Sinclair
Total views: 958
