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Clinical Case Reports Jun 2024[This corrects the article DOI: 10.1002/ccr3.8740.].
[This corrects the article DOI: 10.1002/ccr3.8740.].
PubMed: 38799523
DOI: 10.1002/ccr3.8961 -
BioRxiv : the Preprint Server For... May 2024Glucose-inhibited (GI) neurons of the ventromedial hypothalamus (VMH) depend on neuronal nitric oxide synthase (nNOS) and AMP-activated protein kinase (AMPK) for...
Reducing neuronal nitric oxide synthase (nNOS) expression in the ventromedial hypothalamus (VMH) increases body weight and blood glucose levels while decreasing physical activity in female mice.
Glucose-inhibited (GI) neurons of the ventromedial hypothalamus (VMH) depend on neuronal nitric oxide synthase (nNOS) and AMP-activated protein kinase (AMPK) for activation in low glucose. The Lopez laboratory has shown that the effects of estrogen on brown fat thermogenesis and white fat browning require inhibition of VMH AMPK. This effect of estrogen was mediated by downstream lateral hypothalamus (LH) orexin neurons . We previously showed that estrogen inhibits activation of GI neurons in low glucose by inhibiting AMPK . Thus, we hypothesized that VMH AMPK- and nNOS-dependent GI neurons project to and inhibit orexin neurons. Estrogen inhibition of AMPK in GI neurons would then disinhibit orexin neurons and stimulate brown fat thermogenesis and white fat browning, leading to decreased body weight. To test this hypothesis, we reduced VMH nNOS expression using nNOS shRNA in female mice and measured body weight, adiposity, body temperature, white and brown fat uncoupling protein (UCP1; an index of thermogenesis and browning), locomotor activity, and blood glucose levels. Surprisingly, we saw no effect of reduced VMH nNOS expression on body temperature or UCP1. Instead, body weight and adiposity increased by 30% over 2 weeks post injection of nNOS shRNA. This was associated with increased blood glucose levels and decreased locomotor activity. We also found that VMH nNOS-GI neurons project to the LH. However, stimulation of VMH-LH projections increased excitatory glutamate input onto orexin neurons. Thus, our data do not support our original hypothesis. Excitation of orexin neurons has previously been shown to increase physical activity, leading to decreased blood glucose and body weight . We now hypothesize that VMH nNOS-GI neurons play a role in this latter function of orexin neurons.
PubMed: 38798316
DOI: 10.1101/2024.05.15.594324 -
International Journal of Molecular... May 2024Alzheimer's disease (AD) remains a significant health challenge, with an increasing prevalence globally. Recent research has aimed to deepen the understanding of the... (Review)
Review
Alzheimer's disease (AD) remains a significant health challenge, with an increasing prevalence globally. Recent research has aimed to deepen the understanding of the disease pathophysiology and to find potential therapeutic interventions. In this regard, G protein-coupled receptors (GPCRs) have emerged as novel potential therapeutic targets to palliate the progression of neurodegenerative diseases such as AD. Orexin and cannabinoid receptors are GPCRs capable of forming heteromeric complexes with a relevant role in the development of this disease. On the one hand, the hyperactivation of the orexins system has been associated with sleep-wake cycle disruption and Aβ peptide accumulation. On the other hand, cannabinoid receptor overexpression takes place in a neuroinflammatory environment, favoring neuroprotective effects. Considering the high number of interactions between cannabinoid and orexin systems that have been described, regulation of this interplay emerges as a new focus of research. In fact, in microglial primary cultures of APPSw/Ind mice model of AD there is an important increase in CBR-OXR complex expression, while OXR antagonism potentiates the neuroprotective effects of CBR. Specifically, pretreatment with the OXR antagonist has been shown to strongly potentiate CBR signaling in the cAMP pathway. Furthermore, the blockade of OXR can also abolish the detrimental effects of OXR overactivation in AD. In this sense, CBR-OXR becomes a new potential therapeutic target to combat AD.
Topics: Alzheimer Disease; Animals; Humans; Cannabinoids; Orexins; Orexin Receptors; Receptors, Cannabinoid; Signal Transduction; Amyloid beta-Peptides
PubMed: 38791416
DOI: 10.3390/ijms25105378 -
Brain Sciences May 2024Orexin/hypocretin terminals innervate the dorsal raphe nucleus (DRN), which projects to motor control areas important for spontaneous physical activity (SPA) and energy...
Orexin/hypocretin terminals innervate the dorsal raphe nucleus (DRN), which projects to motor control areas important for spontaneous physical activity (SPA) and energy expenditure (EE). Orexin receptors are expressed in the DRN, and obesity-resistant (OR) rats show higher expression of these receptors in the DRN and elevated SPA/EE. We hypothesized that orexin-A in the DRN enhances SPA/EE and that DRN-GABA modulates the effect of orexin-A on SPA/EE. We manipulated orexin tone in the DRN either through direct injection of orexin-A or through the chemogenetic activation of lateral-hypothalamic (LH) orexin neurons. In the orexin neuron activation experiment, fifteen minutes prior to the chemogenetic activation of orexin neurons, the mice received either the GABA-agonist muscimol or antagonist bicuculline injected into the DRN, and SPA/EE was monitored for 24 h. In a separate experiment, orexin-A was injected into the DRN to study the direct effect of DRN orexin on SPA/EE. We found that the activation of orexin neurons elevates SPA/EE, and manipulation of GABA in the DRN does not alter the SPA response to orexin neuron activation. Similarly, intra-DRN orexin-A enhanced SPA and EE in the mice. These results suggest that orexin-A in the DRN facilitates negative energy balance by increasing physical activity-induced EE, and that modulation of DRN orexin-A is a potential strategy to promote SPA and EE.
PubMed: 38790443
DOI: 10.3390/brainsci14050464 -
Cellular and Molecular Life Sciences :... May 2024CD200 is an anti-inflammatory protein that facilitates signal transduction through its receptor, CD200R, in cells, resulting in immune response suppression. This...
CD200 is an anti-inflammatory protein that facilitates signal transduction through its receptor, CD200R, in cells, resulting in immune response suppression. This includes reducing M1-like macrophages, enhancing M2-like macrophages, inhibiting NK cell cytotoxicity, and downregulating CTL responses. Activation of CD200R has been found to modulate dendritic cells, leading to the induction or enhancement of Treg cells expressing Foxp3. However, the precise mechanisms behind this process are still unclear. Our previous study demonstrated that B cells in Peyer's patches can induce Treg cells, so-called Treg-of-B (P) cells, through STAT6 phosphorylation. This study aimed to investigate the role of CD200 in Treg-of-B (P) cell generation. To clarify the mechanisms, we used wild-type, STAT6 deficient, and IL-24 deficient T cells to generate Treg-of-B (P) cells, and antagonist antibodies (anti-CD200 and anti-IL-20RB), an agonist anti-CD200R antibody, CD39 inhibitors (ARL67156 and POM-1), a STAT6 inhibitor (AS1517499), and soluble IL-20RB were also applied. Our findings revealed that Peyer's patch B cells expressed CD200 to activate the CD200R on T cells and initiate the process of Treg-of-B (P) cells generation. CD200 and CD200R interaction triggers the phosphorylation of STAT6, which regulated the expression of CD200R, CD39, and IL-24 in T cells. CD39 regulated the expression of IL-24, which sustained the expression of CD223 and IL-10 and maintained the cell viability. In summary, the generation of Treg-of-B (P) cells by Peyer's patch B cells was through the CD200R-STAT6-CD39-IL-24 axis pathway.
Topics: Animals; T-Lymphocytes, Regulatory; Mice; B-Lymphocytes; STAT6 Transcription Factor; Mice, Inbred C57BL; Orexin Receptors; Antigens, CD; Signal Transduction; Phosphorylation; Peyer's Patches; Apyrase; Membrane Glycoproteins
PubMed: 38780647
DOI: 10.1007/s00018-024-05268-2 -
Child Neurology Open 2024Pediatric narcolepsy is a complex disorder with unique diagnostic challenges. It is diagnosed with a combination of clinical presentation, polysomnogram with multiple...
Pediatric narcolepsy is a complex disorder with unique diagnostic challenges. It is diagnosed with a combination of clinical presentation, polysomnogram with multiple sleep latency test (PSG with MSLT), and occasionally, hypocretin-1 (orexin) levels in the cerebrospinal fluid (CSF). This report describes a 22-month-old boy experiencing excessive daytime sleepiness (EDS) and frequent falls. The patient was subsequently diagnosed with narcolepsy using hypocretin-1 (orexin) levels. The intent of this report is to establish the utility of using hypocretin-1 (orexin) levels to diagnose narcolepsy type 1 in children who are too young to undergo PSG with MSLT. To our knowledge, there are no reports of narcolepsy in a patient this young. Early recognition and treatment of narcolepsy in children younger than age five may lead to a substantial impact on their cognitive development and minimize potential long- term complications.
PubMed: 38766557
DOI: 10.1177/2329048X231225916 -
Journal of Neuroinflammation May 2024Sepsis-associated encephalopathy (SAE) causes acute and long-term cognitive deficits. However, information on the prevention and treatment of cognitive dysfunction after...
BACKGROUND
Sepsis-associated encephalopathy (SAE) causes acute and long-term cognitive deficits. However, information on the prevention and treatment of cognitive dysfunction after sepsis is limited. The neuropeptide orexin-A (OXA) has been shown to play a protective role against neurological diseases by modulating the inflammatory response through the activation of OXR1 and OXR2 receptors. However, the role of OXA in mediating the neuroprotective effects of SAE has not yet been reported.
METHODS
A mouse model of SAE was induced using cecal ligation perforation (CLP) and treated via intranasal administration of exogenous OXA after surgery. Mouse survival, in addition to cognitive and anxiety behaviors, were assessed. Changes in neurons, cerebral edema, blood-brain barrier (BBB) permeability, and brain ultrastructure were monitored. Levels of pro-inflammatory factors (IL-1β, TNF-α) and microglial activation were also measured. The underlying molecular mechanisms were investigated by proteomics analysis and western blotting.
RESULTS
Intranasal OXA treatment reduced mortality, ameliorated cognitive and emotional deficits, and attenuated cerebral edema, BBB disruption, and ultrastructural brain damage in mice. In addition, OXA significantly reduced the expression of the pro-inflammatory factors IL-1β and TNF-α, and inhibited microglial activation. In addition, OXA downregulated the expression of the Rras and RAS proteins, and reduced the phosphorylation of P-38 and JNK, thus inhibiting activation of the MAPK pathway. JNJ-10,397,049 (an OXR2 blocker) reversed the effect of OXA, whereas SB-334,867 (an OXR1 blocker) did not.
CONCLUSION
This study demonstrated that the intranasal administration of moderate amounts of OXA protects the BBB and inhibits the activation of the OXR2/RAS/MAPK pathway to attenuate the outcome of SAE, suggesting that OXA may be a promising therapeutic approach for the management of SAE.
Topics: Animals; Mice; Sepsis-Associated Encephalopathy; Orexins; Male; Mice, Inbred C57BL; Blood-Brain Barrier; Disease Models, Animal; Administration, Intranasal
PubMed: 38760784
DOI: 10.1186/s12974-024-03111-w -
Cureus Apr 2024Alzheimer's disease (AD) is the most common neurodegenerative condition and a form of dementia encountered in medical practice. Despite many proposed and attempted... (Review)
Review
Alzheimer's disease (AD) is the most common neurodegenerative condition and a form of dementia encountered in medical practice. Despite many proposed and attempted treatments, this disease remains a major puzzle in the public health systems worldwide. The initial part of this article provides an overview and illustration of the primary mechanisms responsible for neuronal damage in AD. Subsequently, it offers a critical evaluation of the most noteworthy studies on pharmacological therapy for AD and outlines recent advancements and novel approaches to managing this condition. Main properties, categorization, Food and Drug Administration (FDA) status, mechanisms of action, benefits, and common side effects of the classical and the most recently proposed pharmacological treatments for AD are described. The conventional pharmacological agents revised comprise cholinesterase inhibitors, monoclonal antibodies, and other therapies, such as memantine, valproic acid, and rosiglitazone. The innovative reviewed pharmacological agents comprise the monoclonal antibodies: donanemab, gantenerumab, solanezumab, bapineuzumab, crenezumab, and semorinemab. Nutritional supplements such as alpha-tocopherol (vitamin E) and caprylidene are also revised. Tau and amyloid-targeting treatments include methylthioninium moiety (MT), leuco-methylthioninium bis (LMTM), an oxidized form of MT, and tramiprosate, which inhibits the beta-amyloid (Aβ) monomer aggregation into toxic oligomers. Antidiabetic and anti-neuroinflammation drugs recently proposed for AD treatment are discussed. The antidiabetic drugs include NE3107, an anti-inflammatory and insulin sensitizer, and the diabetes mainstream drug metformin. The anti-neuroinflammatory AD therapies include the use of sodium oligomannate (GV-971), infusions with intravenous immunoglobulin aiming to decrease plasma levels of the constituents of Aβ plaques, and masitinib, a tyrosine kinase inhibitor that impacts mast and microglia cells. Additional anti-inflammatory agents being currently tested in phase-2 clinical trials, such as atomoxetine (selective norepinephrine reuptake inhibitor), losartan (angiotensin 2 receptor agonist), genistein (anti-inflammatory isoflavone neuroprotective agent), trans-resveratrol (polyphenol antioxidant plant estrogen), and benfotiamine (synthetic thiamine precursor), were reviewed. Lastly, drugs targeting Alzheimer's-associated symptoms, such as brexpiprazole (serotonin dopamine activity modulator) and suvorexant (orexin receptor antagonist), respectively, used for agitation and insomnia in AD patients, are reviewed. As experimental investigations and clinical research progress, there is a possibility that a combination of newly tested medications and traditional ones may emerge as a promising treatment option for AD in the future.
PubMed: 38756263
DOI: 10.7759/cureus.58416 -
Frontiers in Immunology 2024A robust immune response is required for resistance to pulmonary tuberculosis (TB), the primary disease caused by (). However, pharmaceutical inhibition of T cell...
A robust immune response is required for resistance to pulmonary tuberculosis (TB), the primary disease caused by (). However, pharmaceutical inhibition of T cell immune checkpoint molecules can result in the rapid development of active disease in latently infected individuals, indicating the importance of T cell immune regulation. In this study, we investigated the potential role of CD200R during infection, a key immune checkpoint for myeloid cells. Expression of CD200R was consistently downregulated on CD14 monocytes in the blood of subjects with active TB compared to healthy controls, suggesting potential modulation of this important anti-inflammatory pathway. In homogenized TB-diseased lung tissue, CD200R expression was highly variable on monocytes and CD11bHLA-DR macrophages but tended to be lowest in the most diseased lung tissue sections. This observation was confirmed by fluorescent microscopy, which showed the expression of CD200R on CD68 macrophages surrounding TB lung granuloma and found expression levels tended to be lower in macrophages closest to the granuloma core and inversely correlated with lesion size. Antibody blockade of CD200R in a biomimetic 3D granuloma-like tissue culture system led to significantly increased growth. In addition, infection in this system reduced gene expression of CD200R. These findings indicate that regulation of myeloid cells via CD200R is likely to play an important part in the immune response to TB and may represent a potential target for novel therapeutic intervention.
Topics: Humans; Mycobacterium tuberculosis; Tuberculosis, Pulmonary; Myeloid Cells; Orexin Receptors; Macrophages; Adult; Female; Male; Antigens, CD; Middle Aged; Lung; Biomimetics; Monocytes
PubMed: 38745652
DOI: 10.3389/fimmu.2024.1360412 -
Frontiers in Neurology 2024At present, the etiology of narcolepsy is not fully understood, and it is generally believed to be an autoimmune reaction caused by interactions between environmental...
BACKGROUND AND OBJECTIVE
At present, the etiology of narcolepsy is not fully understood, and it is generally believed to be an autoimmune reaction caused by interactions between environmental and genetic factors. Human leukocyte antigen (HLA) class II genes are strongly associated with this gene, especially HLA-DQB1*0602/DQA1*0102. In this study, we mainly analyzed the correlation between different genotypes of HLA-DQB1*0602/DQA1*0102 and clinical manifestations in Chinese patients with narcolepsy.
EXPERIMENTAL METHOD
Narcolepsy patients who were treated at the Department of Neurology, The First Affiliated Hospital of Shandong First Medical University from January 2021 to September 2023 were selected. General information, sleep monitoring data, cerebrospinal fluid (CSF) orexin levels, and human leukocyte antigen gene typing data were collected. The statistical analysis was performed using SPSS 26.0, and the graphs were drawn using GraphPad Prism 9.5.
MAIN RESULTS
A total of 78 patients were included in this study. The DQA1 and DQB1 gene loci were detected in 54 patients, and only the DQB1 gene locus was detected in 24 narcoleptic patients. The most common allele at the HLA-DQB1 locus was *0602 (89.7%), and the most common genotype at this locus was *0602*0301 (19.2%), followed by *0602*0602 (17.9%). The most common phenotype of the HLA-DQA1 locus is *0102 (92.6%), and the most common genotype of this locus is *0102*0102 (27.8%), followed by *0102*0505 (14.8%). There were significant differences ( < 0.05) between HLA-DQB1*0602-positive and HLA-DQB1*0602-negative patients in terms of orexin-A levels, presence or absence of cataplexy, UNS, PSG sleep latency, REM sleep latency, N1 sleep percentage, oxygen depletion index, and average REM latency on the MSLT. The HLA-DQA1*0102-positive and HLA-DQA1*0102-negative patients showed significant differences ( < 0.05) in disease course, presence or absence of sudden onset, PSG REM sleep latency, N1 sleep percentage, and average REM latency on the MSLT. There were significant differences in the average REM latency of the MSLT between HLA-DQB1*0602/DQA1*0102 homozygous and heterozygous patients < 0.05, and no differences were found in the baseline data, orexin-A levels, scale scores, or other sleep parameters.
CONCLUSION
Different genotypes of HLA-DQA1*0102/DQB1*0602 are associated with symptoms of cataplexy in Chinese narcoleptic patients. Homozygous individuals have a shorter mean REM latency in the MSLT, greater genetic susceptibility, and relatively more severe sleepiness.
PubMed: 38725645
DOI: 10.3389/fneur.2024.1379723