scholarly journals Mechanisms Driving Palmitate-Mediated Neuronal Dysregulation in the Hypothalamus

Cells ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 3120
Author(s):  
Calvin V. Lieu ◽  
Neruja Loganathan ◽  
Denise D. Belsham

The hypothalamus maintains whole-body homeostasis by integrating information from circulating hormones, nutrients and signaling molecules. Distinct neuronal subpopulations that express and secrete unique neuropeptides execute the individual functions of the hypothalamus, including, but not limited to, the regulation of energy homeostasis, reproduction and circadian rhythms. Alterations at the hypothalamic level can lead to a myriad of diseases, such as type 2 diabetes mellitus, obesity, and infertility. The excessive consumption of saturated fatty acids can induce neuroinflammation, endoplasmic reticulum stress, and resistance to peripheral signals, ultimately leading to hyperphagia, obesity, impaired reproductive function and disturbed circadian rhythms. This review focuses on the how the changes in the underlying molecular mechanisms caused by palmitate exposure, the most commonly consumed saturated fatty acid, and the potential involvement of microRNAs, a class of non-coding RNA molecules that regulate gene expression post-transcriptionally, can result in detrimental alterations in protein expression and content. Studying the involvement of microRNAs in hypothalamic function holds immense potential, as these molecular markers are quickly proving to be valuable tools in the diagnosis and treatment of metabolic disease.

Reproduction ◽  
2014 ◽  
Vol 148 (1) ◽  
pp. 33-41 ◽  
Author(s):  
Fulu Dong ◽  
Yuan Zhang ◽  
Fei Xia ◽  
Yi Yang ◽  
Sidong Xiong ◽  
...  

MicroRNAs (miRNAs) are non-coding RNA molecules of about 22 nucleotides that involved in post-transcriptional gene regulation. Evidence indicates that miRNAs play essential roles in endometriosis, pre-eclampsia, infertility and other reproductive system diseases. However, whether miRNAs are involved in recurrent spontaneous abortion (RSA) is unclear. In this work, we analysed the miRNA expression profiles in six pairs of villus or decidua from RSA patients and normal pregnancy (NP) women using a human miRNA microarray. Some of the chip results were confirmed by RT-qPCR. In the villi of RSA patients, expression of hsa-miR-184, hsa-miR-187 and hsa-miR-125b-2 was significantly higher, while expression of hsa-miR-520f, hsa-miR-3175 and hsa-miR-4672 was significantly lower, comparing with those of NP control. As well, a total of five miRNAs (hsa-miR-517c, hsa-miR-519a-1, hsa-miR-522, hsa-miR-520h and hsa-miR-184) were upregulated in the decidua of RSA patients. The target genes of these differentially expressed miRNAs were predicted by miRWalk, and we speculate a network of miRNA regulating RSA by target genes function on adhesion, apoptosis and angiogenesis. Our study may help clarify the molecular mechanisms which are involved in the progression of RSA, and provide a reference for future research.


2020 ◽  
Vol 21 (8) ◽  
pp. 2742 ◽  
Author(s):  
Allan Böhm ◽  
Marianna Vachalcova ◽  
Peter Snopek ◽  
Ljuba Bacharova ◽  
Dominika Komarova ◽  
...  

Micro ribonucleic acids (miRNAs) are short non-coding RNA molecules responsible for regulation of gene expression. They are involved in many pathophysiological processes of a wide spectrum of diseases. Recent studies showed their involvement in atrial fibrillation. They seem to become potential screening biomarkers for atrial fibrillation and even treatment targets for this arrhythmia. The aim of this review article was to summarize the latest knowledge about miRNA and their molecular relation to the pathophysiology, diagnosis and treatment of atrial fibrillation.


2013 ◽  
Vol 220 (1) ◽  
pp. 13-24 ◽  
Author(s):  
Anaies Nazarians-Armavil ◽  
Jennifer A Chalmers ◽  
Claire B Lee ◽  
Wenqing Ye ◽  
Denise D Belsham

POMC neurons play a central role in the maintenance of whole-body energy homeostasis. This balance requires proper regulation of POMC neurons by metabolic hormones, such as insulin. However, the heterogeneous cellular population of the intact hypothalamus presents challenges for examining the molecular mechanisms underlying the potent anorexigenic effects of POMC neurons, and there is currently a complete lack of mature POMC neuronal cell models for study. To this end, we have generated novel, immortalized, adult-derived POMC-expressing/α-MSH-secreting cell models, mHypoA-POMC/GFP lines 1–4, representing the fluorescence-activated cell-sorted POMC population from primary POMC-eGFP mouse hypothalamus. The presence of Pomc mRNA in these cell lines was confirmed, and α-MSH was detected via immunofluorescence. α-MSH secretion in the mHypoA-POMC/GFP-1 was found to increase in response to 10 ng/ml ciliary neurotrophic factor (CNTF) or 10 nM insulin as determined by enzyme immunoassay. Further experiments using the mHypoA-POMC/GFP-1 cell line revealed that 10 ng/ml CNTF increases Pomc mRNA at 1 and 2 h after treatment, whereas insulin elicited an increase in Pomc mRNA level and decreases in insulin receptor (Insr (Ir)) mRNA level at 4 h. Furthermore, the activation of IR-mediated downstream second messengers was examined by western blot analysis, following the induction of cellular insulin resistance, which resulted in a loss of insulin-mediated regulation of Pomc and Ir mRNAs. The development of these immortalized neurons will be invaluable for the elucidation of the cellular and molecular mechanisms that underlie POMC neuronal function under normal and perturbed physiological conditions.


Cells ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 859 ◽  
Author(s):  
Jean-François Landrier ◽  
Adel Derghal ◽  
Lourdes Mounien

Metabolic disorders are characterized by the inability to properly use and/or store energy. The burdens of metabolic disease, such as obesity or diabetes, are believed to arise through a complex interplay between genetics and epigenetics predisposition, environment and nutrition. Therefore, understanding the molecular mechanisms for the onset of metabolic disease will provide new insights for prevention and treatment. There is growing concern about the dysregulation of micro-RNAs (miRNAs) in metabolic diseases. MiRNAs are short non-coding RNA molecules that post-transcriptionally repress the expression of genes by binding to untranslated regions and coding sequences of the target mRNAs. This review aims to provide recent data about the potential involvement of miRNAs in metabolic diseases, particularly obesity and type 2 diabetes.


2018 ◽  
Vol 315 (2) ◽  
pp. E133-E140 ◽  
Author(s):  
Erika K. Tse ◽  
Ashkan Salehi ◽  
Matthew N. Clemenzi ◽  
Denise D. Belsham

The brain, specifically the hypothalamus, controls whole body energy and glucose homeostasis through neurons that synthesize specific neuropeptides, whereas hypothalamic dysfunction is linked directly to insulin resistance, obesity, and type 2 diabetes mellitus. Nutrient excess, through overconsumption of a Western or high-fat diet, exposes the hypothalamus to high levels of free fatty acids, which induces neuroinflammation, endoplasmic reticulum stress, and dysregulation of neuropeptide synthesis. Furthermore, exposure to a high-fat diet also disrupts normal circadian rhythms, and conversely, clock gene knockout models have symptoms of metabolic disorders. While whole brain/animal studies have provided phenotypic end points and important clues to the genes involved, there are still major gaps in our understanding of the intracellular pathways and neuron-specific components that ultimately control circadian rhythms and energy homeostasis. Because of its complexity and heterogeneous nature, containing a diverse mix cell types, it is difficult to dissect the critical hypothalamic components involved in these processes. Of significance, we have the capacity to study these individual components using an extensive collection of both embryonic- and adult-derived, immortalized hypothalamic neuronal cell lines from rodents. These defined neuronal cell lines have been used to examine the impact of nutrient excess, such as palmitate, on circadian rhythms and neuroendocrine signaling pathways, as well as changes in vital neuropeptides, leading to the development of neuronal inflammation; the role of proinflammatory molecules in this process; and ultimately, restoration of normal signaling, clock gene expression, and neuropeptide synthesis in disrupted states by beneficial anti-inflammatory compounds in defined hypothalamic neurons.


2020 ◽  
Vol 40 (1) ◽  
pp. 25-49 ◽  
Author(s):  
Nishan Sudheera Kalupahana ◽  
Bimba Lakmini Goonapienuwala ◽  
Naima Moustaid-Moussa

White adipose tissue (WAT) and brown adipose tissue (BAT) are involved in whole-body energy homeostasis and metabolic regulation. Changes to mass and function of these tissues impact glucose homeostasis and whole-body energy balance during development of obesity, weight loss, and subsequent weight regain. Omega-3 polyunsaturated fatty acids (ω-3 PUFAs), which have known hypotriglyceridemic and cardioprotective effects, can also impact WAT and BAT function. In rodent models, these fatty acids alleviate obesity-associated WAT inflammation, improve energy metabolism, and increase thermogenic markers in BAT. Emerging evidence suggests that ω-3 PUFAs can also modulate gut microbiota impacting WAT function and adiposity. This review discusses molecular mechanisms, implications of these findings, translation to humans, and future work, especially with reference to the potential of these fatty acids in weight loss maintenance.


Cells ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1620
Author(s):  
Danyel Fernandes Contiliani ◽  
Yasmin de Araújo Ribeiro ◽  
Vitor Nolasco de Moraes ◽  
Tiago Campos Pereira

MicroRNAs (miRNAs) are small non-coding RNA molecules able to post-transcriptionally regulate gene expression via base-pairing with partially complementary sequences of target transcripts. Prion diseases comprise a singular group of neurodegenerative conditions caused by endogenous, misfolded pathogenic (prion) proteins, associated with molecular aggregates. In humans, classical prion diseases include Creutzfeldt–Jakob disease, fatal familial insomnia, Gerstmann–Sträussler–Scheinker syndrome, and kuru. The aim of this review is to present the connections between miRNAs and prions, exploring how the interaction of both molecular actors may help understand the susceptibility, onset, progression, and pathological findings typical of such disorders, as well as the interface with some prion-like disorders, such as Alzheimer’s. Additionally, due to the inter-regulation of prions and miRNAs in health and disease, potential biomarkers for non-invasive miRNA-based diagnostics, as well as possible miRNA-based therapies to restore the levels of deregulated miRNAs on prion diseases, are also discussed. Since a cure or effective treatment for prion disorders still pose challenges, miRNA-based therapies emerge as an interesting alternative strategy to tackle such defying medical conditions.


2012 ◽  
Vol 303 (7) ◽  
pp. E832-E840 ◽  
Author(s):  
Veronica Resi ◽  
Subhabrata Basu ◽  
Maricela Haghiac ◽  
Larraine Presley ◽  
Judi Minium ◽  
...  

Changes in adipose tissue metabolism are central to adaptation of whole body energy homeostasis to pregnancy. To gain insight into the molecular mechanisms supporting tissue remodeling, we have characterized the longitudinal changes of the adipose transcriptome in human pregnancy. Healthy nonobese women recruited pregravid were followed in early (8–12 wk) and in late (36–38 wk) pregnancy. Adipose tissue biopsies were obtained in the fasting state from the gluteal depot. The adipose transcriptome was examined via whole genome DNA microarray. Expression of immune-related genes and extracellular matrix components was measured using real-time RT-PCR. Adipose mass, adipocyte size, and cell number increased in late pregnancy compared with pregravid measurements ( P < 0.001) but remained unchanged in early pregnancy. The adipose transcriptome evolved during pregnancy with 10–15% of genes being differently expressed compared with pregravid. Functional gene cluster analysis revealed that the early molecular changes affected immune responses, angiogenesis, matrix remodeling, and lipid biosynthesis. Increased expression of macrophage markers (CD68, CD14, and the mannose-6 phosphate receptor) emphasized the recruitment of the immune network in both early and late pregnancy. The TLR4/NF-κB signaling pathway was enhanced specifically in relation to inflammatory adipokines and chemokines genes. We conclude that early recruitment of metabolic and immune molecular networks precedes the appearance of pregnancy-related physiological changes in adipose tissue. This biphasic pattern suggests that physiological inflammation is an early step preceding the development of insulin resistance, which peaks in late pregnancy.


Ceiba ◽  
2016 ◽  
Vol 54 (1) ◽  
pp. 50-58
Author(s):  
Robert P. Rhoads ◽  
Lance H. Baumgard ◽  
Lidan Zhao

At the onset of heat stress, cattle initiate a series of whole body adaptations in an effort to cope with and dissipate additional heat load. These include well-known physiological changes such as increased respiration rate and sweating rate and decreased feed intake. Environmentally induced hyperthermia in ruminants depresses production as a consequence of reduced feed intake but it is unclear how shifts in metabolism may further affect production performance and physiological acclimation. Our evidence indicates that cattle experiencing heat stress do not appear to engage metabolic and glucose-sparing adaptations consistent with their plane of nutrition. In this context, the liver is uniquely positioned to direct exogenously and endogenously derived nutrients for use by other metabolically active tissues such as the mammary gland and skeletal muscle. Despite the prominent role of the liver in whole-body metabolism, alterations in the molecular mechanisms leading to hepatic adaptation during heat challenge are unclear. We are using management tools and metabolic modifiers, such as bovine somatotropin, in an attempt to better understand and improve hepatic function during heat stress. Because a large proportion of an animal’s mass is comprised of skeletal muscle, alterations in skeletal muscle metabolism and function can have a profound impact on whole-animal energy metabolism and nutrient homeostasis especially during periods of stress.  We have initiated studies to understand how hyperthermia influences the set points of several metabolic pathways within skeletal muscle. It appears that during heat stress bovine skeletal muscle experiences mitochondrial dysfunction leading to impaired cellular energy status. Finally, investigations into adipose tissue metabolism demonstrate impaired lipolytic functions likely due to a refractory nature to adrenergic stimuli. Taken together, this may have broad implications for the reduced production and heat intolerance seen during heat stress especially if tissue(s) are not able to make necessary contributions to whole-body energy homeostasis. Accurately understanding the biological mechanism(s) by which thermal stress reduces animal performance is critical for developing novel approaches (i.e. genetic, managerial and nutritional) to preserve growth and lactation especially given the critical importance of nutrients, such as glucose, to animal production and well being in these situations.


Cancers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3378
Author(s):  
Andreea D. Lazăr ◽  
Sorina Dinescu ◽  
Marieta Costache

Considered to be highly lethal if not diagnosed in early stages, cutaneous malignant melanoma is among the most aggressive and treatment-resistant human cancers, and its incidence continues to rise, largely due to ultraviolet radiation exposure, which is the main carcinogenic factor. Over the years, researchers have started to unveil the molecular mechanisms by which malignant melanoma can be triggered and sustained, in order to establish specific, reliable biomarkers that could aid the prognosis and diagnosis of this fatal disease, and serve as targets for development of novel efficient therapies. The high mutational burden and heterogeneous nature of melanoma shifted the main focus from the genetic landscape to epigenetic and epitranscriptomic modifications, aiming at elucidating the role of non-coding RNA molecules in the fine tuning of melanoma progression. Here we review the contribution of microRNAs and lncRNAs to melanoma invasion, metastasis and acquired drug resistance, highlighting their potential for clinical applications as biomarkers and therapeutic targets.


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