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Benefits of Circulating Human Metabolites from Fish Cartilage Hydrolysate on Primary Human Dermal Fibroblasts, an Ex Vivo Clinical Investigation for Skin Health Applications.
Nutrients
Fabien Wauquier, Line Boutin-Wittrant, Elodie Bouvret +5 more
Due to its significant exposure to stressful environmental factors, the skin undergoes a high remodeling rate over time, which alters not only its appearance but also its functionality. This alteration of the skin, namely photoaging, is characterized by dryness and a loss of elasticity that mainly originates from the dysregulation of dermal fibroblast activities. In order to overcome such tissue outcome, cosmetic products have evolved toward nutricosmetics, thus promoting beauty from within. Among bio-actives of interest, bio-peptides deriving from plant or animal sources may exert various biological activities beyond their nutritional value. However, studies remain mostly descriptive and the mode of action at the cellular level in clinic remains a concern. In a recent clinical trial, it was showed that supplementation with a fish cartilage hydrolysate (FCH) improved signs of chronological and photoaging-induced skin changes in healthy women. Here, using an original ex vivo clinical approach adapted to nutricosmetic purpose, we further demonstrated that this fish cartilage hydrolysate was absorbed and that the circulating metabolites produced in humans following FCH intake stimulate human dermal fibroblast growth, promote specific hyaluronan production, up-regulate elastin synthesis and inhibit MMP-1 and 3 expression along with the enhancement of TGF-β release. Altogether, these data provide clues on the mechanisms likely contributing to the beneficial impact of FCH on human skin functionality by supporting hydration, elasticity and limiting the expression of catabolic factors involved in photoaging onset.
Brief Opioid Exposure Paradoxically Augments Primary Afferent Input to Spinal Excitatory Neurons via α2δ-1-Dependent Presynaptic NMDA Receptors.
J Neurosci
Shao-Rui Chen, Hong Chen, Daozhong Jin +1 more
Treatment with opioids not only inhibits nociceptive transmission but also elicits a rebound and persistent increase in primary afferent input to the spinal cord. Opioid-elicited long-term potentiation (LTP) from TRPV1-expressing primary afferents plays a major role in opioid-induced hyperalgesia and analgesic tolerance. Here, we determined whether opioid-elicited LTP involves vesicular glutamate transporter-2 (VGluT2) or vesicular GABA transporter (VGAT) neurons in the spinal dorsal horn of male and female mice and identified underlying signaling mechanisms. Spinal cord slice recordings revealed that µ-opioid receptor (MOR) stimulation with DAMGO initially inhibited dorsal root-evoked EPSCs in 87% VGluT2 neurons and subsequently induced LTP in 49% of these neurons. Repeated morphine treatment increased the prevalence of VGluT2 neurons displaying LTP with a short onset latency. In contrast, DAMGO inhibited EPSCs in 46% VGAT neurons but did not elicit LTP in any VGAT neurons even in morphine-treated mice. Spinal superficial laminae were densely innervated by MOR-containing nerve terminals and were occupied by mostly VGluT2 neurons and few VGAT neurons. Furthermore, conditional Grin1 knockout in dorsal root ganglion neurons diminished DAMGO-elicited LTP in lamina II neurons and attenuated hyperalgesia and analgesic tolerance induced by repeated treatment with morphine. In addition, DAMGO-elicited LTP in VGluT2 neurons was abolished by protein kinase C inhibition, gabapentin, Cacna2d1 knockout, or disrupting the α2δ-1-NMDA receptor interaction with an α2δ-1 C terminus peptide. Thus, brief MOR stimulation distinctively potentiates nociceptive primary afferent input to excitatory dorsal horn neurons via α2δ-1-coupled presynaptic NMDA receptors, thereby causing hyperalgesia and reducing analgesic actions of opioids.SIGNIFICANCE STATEMENT Opioid drugs are potent analgesics for treating severe pain and are commonly used during general anesthesia. However, opioid use often induces pain hypersensitivity, rapid loss of analgesic efficacy, and dose escalation, which can cause dependence, addiction, and even overdose fatality. This study demonstrates for the first time that brief opioid exposure preferentially augments primary sensory input to genetically identified glutamatergic excitatory, but not GABAergic/glycinergic inhibitory, neurons in nociceptive dorsal horn circuits. This opioid-elicited synaptic plasticity is cell type specific and mediated by protein kinase C-dependent and α2δ-1-dependent activation of NMDA receptors at primary sensory nerve terminals. These findings elucidate how intraoperative use of opioids for preemptive analgesia paradoxically aggravates postoperative pain and increases opioid consumption and suggest new strategies to improve opioid analgesic efficacy.
SH3- and actin-binding domains connect ADNP and SHANK3, revealing a fundamental shared mechanism underlying autism.
Mol Psychiatry
Yanina Ivashko-Pachima, Maram Ganaiem, Inbar Ben-Horin-Hazak +10 more
De novo heterozygous mutations in activity-dependent neuroprotective protein (ADNP) cause autistic ADNP syndrome. ADNP mutations impair microtubule (MT) function, essential for synaptic activity. The ADNP MT-associating fragment NAPVSIPQ (called NAP) contains an MT end-binding protein interacting domain, SxIP (mimicking the active-peptide, SKIP). We hypothesized that not all ADNP mutations are similarly deleterious and that the NAPV portion of NAPVSIPQ is biologically active. Using the eukaryotic linear motif (ELM) resource, we identified a Src homology 3 (SH3) domain-ligand association site in NAP responsible for controlling signaling pathways regulating the cytoskeleton, namely NAPVSIP. Altogether, we mapped multiple SH3-binding sites in ADNP. Comparisons of the effects of ADNP mutations p.Glu830synfs*83, p.Lys408Valfs*31, p.Ser404* on MT dynamics and Tau interactions (live-cell fluorescence-microscopy) suggested spared toxic function in p.Lys408Valfs*31, with a regained SH3-binding motif due to the frameshift insertion. Site-directed-mutagenesis, abolishing the p.Lys408Valfs*31 SH3-binding motif, produced MT toxicity. NAP normalized MT activities in the face of all ADNP mutations, although, SKIP, missing the SH3-binding motif, showed reduced efficacy in terms of MT-Tau interactions, as compared with NAP. Lastly, SH3 and multiple ankyrin repeat domains protein 3 (SHANK3), a major autism gene product, interact with the cytoskeleton through an actin-binding motif to modify behavior. Similarly, ELM analysis identified an actin-binding site on ADNP, suggesting direct SH3 and indirect SHANK3/ADNP associations. Actin co-immunoprecipitations from mouse brain extracts showed NAP-mediated normalization of Shank3-Adnp-actin interactions. Furthermore, NAP treatment ameliorated aberrant behavior in mice homozygous for the Shank3 ASD-linked InsG3680 mutation, revealing a fundamental shared mechanism between ADNP and SHANK3.
Intranasal Peptide Therapeutics: A Promising Avenue for Overcoming the Challenges of Traditional CNS Drug Development.
Cells
Meenakshi Bose, Gabriela Farias Quipildor, Michelle E Ehrlich +1 more
The central nervous system (CNS) has, among all organ systems in the human body, the highest failure rate of traditional small-molecule drug development, ranging from 80-100% depending on the area of disease research. This has led to widespread abandonment by the pharmaceutical industry of research and development for CNS disorders, despite increased diagnoses of neurodegenerative disorders and the continued lack of adequate treatment options for brain injuries, stroke, neurodevelopmental disorders, and neuropsychiatric illness. However, new approaches, concurrent with the development of sophisticated bioinformatic and genomic tools, are being used to explore peptide-based therapeutics to manipulate endogenous pathways and targets, including "undruggable" intracellular protein-protein interactions (PPIs). The development of peptide-based therapeutics was previously rejected due to systemic off-target effects and poor bioavailability arising from traditional oral and systemic delivery methods. However, targeted nose-to-brain, or intranasal (IN), approaches have begun to emerge that allow CNS-specific delivery of therapeutics via the trigeminal and olfactory nerve pathways, laying the foundation for improved alternatives to systemic drug delivery. Here we review a dozen promising IN peptide therapeutics in preclinical and clinical development for neurodegenerative (Alzheimer's, Parkinson's), neuropsychiatric (depression, PTSD, schizophrenia), and neurodevelopmental disorders (autism), with insulin, NAP (davunetide), IGF-1, PACAP, NPY, oxytocin, and GLP-1 agonists prominent among them.
The Role of Tβ4-POP-Ac-SDKP Axis in Organ Fibrosis.
Int J Mol Sci
Wei Wang, Wenning Jia, Chunping Zhang
Fibrosis is a pathological process in which parenchymal cells are necrotic and excess extracellular matrix (ECM) is accumulated due to dysregulation of tissue injury repair. Thymosin β4 (Tβ4) is a 43 amino acid multifunctional polypeptide that is involved in wound healing. Prolyl oligopeptidase (POP) is the main enzyme that hydrolyzes Tβ4 to produce its derivative N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP) which is found to play a role in the regulation of fibrosis. Accumulating evidence suggests that the Tβ4-POP-Ac-SDKP axis widely exists in various tissues and organs including the liver, kidney, heart, and lung, and participates in the process of fibrogenesis. Herein, we aim to elucidate the role of Tβ4-POP-Ac-SDKP axis in hepatic fibrosis, renal fibrosis, cardiac fibrosis, and pulmonary fibrosis, as well as the underlying mechanisms. Based on this, we attempted to provide novel therapeutic strategies for the regulation of tissue damage repair and anti-fibrosis therapy. The Tβ4-POP-Ac-SDKP axis exerts protective effects against organ fibrosis. It is promising that appropriate dosing regimens that rely on this axis could serve as a new therapeutic strategy for alleviating organ fibrosis in the early and late stages.
Beneficial effects of SS-31 peptide on cardiac mitochondrial dysfunction in tafazzin knockdown mice.
Sci Rep
Silvia Russo, Domenico De Rasmo, Anna Signorile +2 more
Barth Syndrome (BTHS), a genetic disease associated with early-onset cardioskeletal myopathy, is caused by loss-of-function mutations of the TAFAZZIN gene, which is responsible for remodeling the mitochondrial phospholipid cardiolipin (CL). Deregulation of CL biosynthesis and maturation in BTHS mitochondria result in a dramatically increased monolysocardiolipin (MLCL)/CL ratio associated with bioenergetic dysfunction. One of the most promising therapeutic approaches for BTHS includes the mitochondria-targeted tetrapeptide SS-31, which interacts with CL. Here, we used TAFAZZIN knockdown (TazKD) mice to investigate for the first time whether in vivo administration of SS-31 could affect phospholipid profiles and mitochondrial dysfunction. The CL fingerprinting of TazKD cardiac mitochondria obtained by MALDI-TOF/MS revealed the typical lipid changes associated with BTHS. TazKD mitochondria showed lower respiratory rates in state 3 and 4 together with a decreased in maximal respiratory rates. Treatment of TazKD mice with SS-31 improved mitochondrial respiratory capacity and promoted supercomplex organization, without affecting the MLCL/CL ratio. We hypothesize that SS-31 exerts its effect by influencing the function of the respiratory chain rather than affecting CL directly. In conclusion, our results indicate that SS-31 have beneficial effects on improving cardiac mitochondrial dysfunction in a BTHS animal model, suggesting the peptide as future pharmacologic agent for therapy.
Aging Increases Susceptibility to Develop Cardiac Hypertrophy following High Sugar Consumption.
Nutrients
Ana P Valencia, Jeremy A Whitson, Shari Wang +4 more
Aging and poor diet are independent risk factors for heart disease, but the impact of high-sucrose (HS) consumption in the aging heart is understudied. Aging leads to impairments in mitochondrial function that result in muscle dysfunction (e.g., cardiac remodeling and sarcopenia). We tested whether HS diet (60%kcal sucrose) would accelerate muscle dysfunction in 24-month-old male CB6F1 mice. By week 1 on HS diet, mice developed significant cardiac hypertrophy compared to age-matched chow-fed controls. The increased weight of the heart persisted throughout the 4-week treatment, while body weight and strength declined more rapidly than controls. We then tested whether HS diet could worsen cardiac dysfunction in old mice and if the mitochondrial-targeted drug, elamipretide (ELAM), could prevent the diet-induced effect. Old and young mice were treated with either ELAM or saline as a control for 2 weeks, and provided with HS diet or chow on the last week. As demonstrated in the previous experiment, old mice had age-related cardiac hypertrophy that worsened after one week on HS and was prevented by ELAM treatment, while the HS diet had no detectable effect on hypertrophy in the young mice. As expected, mitochondrial respiration and reactive oxygen species (ROS) production were altered by age, but were not significantly affected by HS diet or ELAM. Our findings highlight the vulnerability of the aged heart to HS diet that can be prevented by systemic targeting of the mitochondria with ELAM.
Skin-adaptive film dressing with smart-release of growth factors accelerated diabetic wound healing.
Int J Biol Macromol
Yingzheng Zhao, Lantian Huang, Gaolong Lin +7 more
The general treatment of diabetic wound was use of wound dressings to absorb excess exudate. However, traditional wound dressings neither mimic the skin-like properties nor easily be withdrawn from the wound. Herein, the skin-adaptive three-layered films (AGB) dressing has been designed by alternatively depositing phenylboronic acid-grafted γ-PGA (PBA-PGA) and polyvinyl alcohol (PVA). The thickness of AGB film was only 479 μm and its flexibility was obviously strengthen by the boronic ester cross-linking. Besides, the dry AGB film was conveniently adhered to the fresh wound, where its adhesive force reached to 1267 ± 330 mN. Moreover, the adhered AGB film was easily peeled without any second damage after hydration. An anti-inflammatory tripeptide (KPV) and epidermal growth factor (EGF) as biologic factors were respectively encapsulated in the bottom layer and the middle-top two layers of AGB film. KPV was firstly released within 3 day and EGF was subsequently released in a glucose-responsive manner. AGB film containing KPV and EGF (K-E-AGB) could significantly improve the repair rate of full-thickness skin wound on diabetic mice. The mechanism of wound healing was associated with inflammatory inhibition, angiogenesis and collagen deposition. Collectively, skin-adaptive film may be a promising dressing as delivery of biologic factors for the chronic wound.
Selank, a Peptide Analog of Tuftsin, Attenuates Aversive Signs of Morphine Withdrawal in Rats.
Bull Exp Biol Med
M A Konstantinopolsky, I V Chernyakova, L G Kolik
Activity of a peptide tuftsin analogue Selank was studied in outbred rats using the naloxone-precipitated morphine withdrawal model. Single intraperitoneal injection of Selank in an anxiolytic dose of 0.3 mg/kg reduced the total index of morphine withdrawal syndrome by 39.6%, significantly (р<0.0001) attenuated convulsive reactions, ptosis, and posture disorders, and 9-fold increased the tactile sensitivity threshold in morphine-dependent rats in comparison with the group of active control; at the same time, Selank was slightly inferior to diazepam in a dose of 2 mg/kg by pharmacological activity (the decrease in total index of morphine withdrawal syndrome by 49.3% and 13-fold increase in sensitivity threshold). Thus, Selank, like diazepam, weakens the aversive signs of morphine withdrawal in rats with opiate dependence.
Provocative tests with Kisspeptin-10 and GnRH set the scene for determining social status and environmental impacts on reproductive capacity in male African lions (Panthera leo).
Gen Comp Endocrinol
Mike Ludwig, Claire Newton, Ané Pieters +4 more
Understanding the hypothalamic factors regulating reproduction facilitates maximising the reproductive success of breeding programmes and in the management and conservation of threatened species, including African lions. To provide insight into the physiology and pathophysiology of the hypothalamic-pituitary-gonadal reproductive axis in lions, we studied the luteinising hormone (LH) and steroid hormone responses to gonadotropin-releasing hormone (GnRH) and its upstream regulator, kisspeptin. Six young (13.3 ± 1.7 months, 56.2 ± 4.3 kg) and four adult (40.2 ± 1.4 months, 174 ± 6 kg) male lions (Ukutula Conservation Centre, South Africa) were used in this study. Lions were immobilised with a combination of medetomidine and ketamine and an intravenous catheter was placed in a jugular, cephalic or medial saphenous vein for blood sampling at 10-min intervals for 220 min. The ten-amino acid kisspeptin which has full intrinsic activity (KP-10, 1 µg/kg) and GnRH (1 µg/kg) were administered intravenously to study their effects on LH and steroid hormone plasma concentrations, measured subsequently by ELISA and liquid chromatography tandem mass spectrometry (LC-MS/MS), respectively. Basal LH levels were similarly low between the age groups, but testosterone and its precursor levels were higher in the adult animals. Adult lions showed a significant LH response to KP-10 (10-fold) and GnRH (11-fold) administration (p < 0.05 and P < 0.001, respectively) whereas in young lions LH increased significantly only in response to GnRH. In adults alone, testosterone and its precursors steadily increased in response to KP-10, with no significant further increase in response to GnRH. Plasma levels of glucocorticoids in response to KP-10 remained unchanged. We suggest that provocative testing of LH and steroid stimulation with kisspeptin provides a new and sensitive tool for determining reproductive status and possibly an index of exposure to stress, environmental insults such as disease, endocrine disruptors and nutritional status. 272 words.
Mitochondrial derived peptide MOTS-c prevents the development of heart failure under pressure overload conditions in mice.
J Cell Mol Med
Peng Zhong, Jianye Peng, Yewen Hu +2 more
MOTS-c, a mitochondrial-derived peptide (MDP), has been shown to have multiple biological activities such as antioxidation, anti-inflammation, and anti-apoptosis properties. In the present study, we aimed at evaluating the therapeutic effect of MOTS-c peptide in an animal model of heart failure. The heart failure mouse model was made by transverse aortic constriction (TAC) operations. The MOTS-c peptide was administrated subcutaneously by using an osmotic pump. At the end of the animal experiment, cardiac function was evaluated by echocardiography, and heart tissues were subjected to histological and molecular analysis. In vitro cultured H9C2 cells were used to test the effects of MOTS-c overexpression on cell death in response to H2 O2 stimulation. Our study showed that MOTS-c peptide attenuated TAC-induced cardiac dysfunction and remodelling. In addition, the MOTS-c peptide reduced the inflammatory response and upregulated the antioxidant capacity, coupled with the activation of the AMPK pathway in the heart of the TAC mouse model. In in vitro cultured cardiac cells, overexpression of MOTS-c was shown to activate the AMPK pathway and protect cell apoptosis in response to H2 O2 stimulation. Taken together, our study suggested that MOTS-c peptides may have therapeutic potential in treating HF.
Pharmacologic therapeutic options for sexual dysfunction.
Curr Opin Obstet Gynecol
Claire S Burton, Kavita Mishra
Sexual problems are reported by up to 45% of individuals assigned female at birth. Although sexual function is a complex biopsychosocial construct, there are a number of pharmacologic treatment options aimed at addressing the changing vaginal hormonal milieu in postmenopausal individuals and moderating the excitatory and inhibitory aspects of the central nervous system in those with hypoactive sexual desire disorder.
The antimicrobial peptide Magainin-2 interacts with BamA impairing folding of E. coli membrane proteins.
Front Chem
Angela Di Somma, Carolina Cané, Antonio Moretta +6 more
Antimicrobial peptides (AMPs) are a unique and diverse group of molecules endowed with a broad spectrum of antibiotics properties that are being considered as new alternative therapeutic agents. Most of these peptides are membrane-active molecules, killing bacteria by membrane disruption. However, recently an increasing number of AMPs was shown to enter bacterial cells and target intracellular processes fundamental for bacterial life. In this paper we investigated the mechanism of action of Maganin-2 (Mag-2), a well-known antimicrobial peptide isolated from the African clawed frog Xenopus laevis, by functional proteomic approaches. Several proteins belonging to E. coli macromolecular membrane complexes were identified as Mag-2 putative interactors. Among these, we focused our attention on BamA a membrane protein belonging to the BAM complex responsible for the folding and insertion of nascent β-barrel Outer Membrane Proteins (OMPs) in the outer membrane. In silico predictions by molecular modelling, in vitro fluorescence binding and Light Scattering experiments carried out using a recombinant form of BamA confirmed the formation of a stable Mag-2/BamA complex and indicated a high affinity of the peptide for BamA. Functional implications of this interactions were investigated by two alternative and complementary approaches. The amount of outer membrane proteins OmpA and OmpF produced in E. coli following Mag-2 incubation were evaluated by both western blot analysis and quantitative tandem mass spectrometry in Multiple Reaction Monitoring scan mode. In both experiments a gradual decrease in outer membrane proteins production with time was observed as a consequence of Mag-2 treatment. These results suggested BamA as a possible good target for the rational design of new antibiotics since this protein is responsible for a crucial biological event of bacterial life and is absent in humans.
Exercise and Metabolic Health: The Emerging Roles of Novel Exerkines.
Curr Protein Pept Sci
İbrahim Türkel, Berkay Özerkliğ, Muhammed M Atakan +3 more
Physical inactivity is a major cause of chronic diseases. It shortens the health span by lowering the age of the first chronic disease onset, which leads to decreased quality of life and increased mortality risk. On the other hand, physical exercise is considered a miracle cure in the primary prevention of at least 35 chronic diseases, including obesity, insulin resistance, and type 2 diabetes. However, despite many scientific attempts to unveil the health benefits conferred by regular exercise, the underlying molecular mechanisms driving such benefits are not fully explored. Recent research shows that exercise-induced bioactive molecules, named exerkines, might play a critical role in the regulation of metabolic homeostasis and thus prevent metabolic diseases. Here we summarize the current understanding of the health-promoting effects of exerkines secreted from skeletal muscle, adipose tissue, bone, and liver, including MOTS-c, BDNF, miR-1, 12,13-diHOME, irisin, SPX, OC, GDF15, and FGF21 on obesity, insulin resistance, and type 2 diabetes. Identifying the systemic health benefits of exerkines may open a new area for the discovery of new pharmacological strategies for the prevention and management of metabolic diseases.
Effect of nootropic dipeptide noopept on CA1 pyramidal neurons involves α7AChRs on interneurons in hippocampal slices from rat.
Neurosci Lett
Rodion V Kondratenko, Igor S Povarov, Sergey N Kolbaev +5 more
Noopept (NP) is a proline-containing dipeptide with nootropic and neuroprotective properties. We have previously shown that NP significantly increased the frequency of spontaneous IPSCs in hippocampal CA1 pyramidal cells mediated by the activation of inhibitory interneurons in stratum radiatum. The cholinergic system plays an important role in the performance of cognitive functions, furthermore multiple behavioral and clinical facts link NP with the cholinergic system. The present study was undertaken to reveal the possible interaction of NP with neuronal nicotinic acetylcholine receptors (nAChRs). Currents were recorded from rat hippocampal neurons using the whole-cell, patch-clamp technique. NP (5 µM) increased the action potential firing frequency recorded from GABAergic interneurons in the stratum radiatum (SR) of CA1 region. This effect was almost completely abolished by the application of the α7 nAChR-selective antagonists α-bungarotoxin (α-BGT; 6 nM) and methyllycaconitine (MLA; 20 nM). The increase in the frequency of spontaneous IPSCs in CA1 pyramidal cells induced by NP was also eliminated by α7 nAChRs antagonists. These results imply the involvement of α7 nAChRs in the modulation of hippocampal neuronal activity caused by NP and indicate that a7 nAChRs are an important site of action of NP.
CAN'T INTUBATE, CAN'T OXYGENATE: 
A RARE CASE OF A DIFFICULT AIRWAY DUE TO NONHEREDITARY ANGIOEDEMA.
Acta Clin Croat
Điđi Delalić, Vinko Borčić, Ingrid Prkačin
Angioedema is a form of allergic mediated by histamine and non-allergic mediated by bradykinin and can be lethal if not recognized and treated promptly. This case demonstrates the proper diagnosis of and intervention in rapid onset severe angioedema. A 68-year-old male came to the emergency department with a complaint of dyspnea that started two hours before. He had type II diabetes, chronic kidney disease and several different antihypertensive medications, including an ACE inhibitor for hypertension. During physical examination, the patient was hypertensive, tachycardic, tachypnoic, and edematous. During his stay in the ED he was treated with a combination of corticosteroids, antihistamines and epinephrine, but the patient's edema and dyspnea worsened and his oxygen saturation started to deteriorate with a progression of skin edema. Intubation was not possible due to the large edema of the tongue, so a tracheotomy was done. An ampule of icatibant was administered and rapid regression of the edema, along with the stabilization of the patient's vital signs, followed after five minutes. The patient was discharged home after five days with a recommendation of discontinuing the ACE inhibitor. While non-hereditary angioedema is not a rare condition, emergency physicians should be adequately educated about it.
GDF11 Regulates PC12 Neural Stem Cells via ALK5-Dependent PI3K-Akt Signaling Pathway.
Int J Mol Sci
Zongkui Wang, Peng Jiang, Fengjuan Liu +9 more
Growth differentiation factor 11 (GDF11), belonging to the transforming factor-β superfamily, regulates anterior-posterior patterning and inhibits neurogenesis during embryonic development. However, recent studies recognized GDF11 as a rejuvenating (or anti-ageing) factor to reverse age-related cardiac hypertrophy, repair injured skeletal muscle, promote cognitive function, etc. The effects of GDF11 are contradictory and the mechanism of action is still not well clarified. The objective of the present study was to investigate effects of GDF11 on PC12 neural stem cells in vitro and to reveal the underlying mechanism. We systematically assessed the effects of GDF11 on the life activities of PC12 cells. GDF11 significantly suppressed cell proliferation and migration, promoted differentiation and apoptosis, and arrested cell cycle at G2/M phase. Both TMT-based proteomic analysis and phospho-antibody microarray revealed PI3K-Akt pathway was enriched when treated with GDF11. Inhibition of ALK5 or PI3K obviously attenuated the effects of GDF11 on PC12 neural stem cells, which exerted that GDF11 regulated neural stem cells through ALK5-dependent PI3K-Akt signaling pathway. In summary, these results demonstrated GDF11 could be a negative regulator for neurogenesis via ALK5 activating PI3K-Akt pathway when it directly acted on neural stem cells.
Skeletal muscle mitochondrial remodeling in heart failure: An update on mechanisms and therapeutic opportunities.
Biomed Pharmacother
Jiayu Lv, Yumeng Li, Shuqing Shi +4 more
Patients with heart failure (HF) usually present with skeletal muscle diseases of varying severity, ranging from early fatigue on exercise to sarcopenia, sarcopenic obesity or cachexia, and frailty, which are significant predictors of HF prognosis. Abnormal mitochondrial metabolism has been identified as one of the earliest signs of skeletal muscle injury in HF and is associated with pathological alterations in muscle, manifested as muscle wasting, myocyte atrophy and apoptosis, fiber type shift, impaired contractile coupling, and muscle fat infiltration. In this review, we update the evidence for skeletal muscle mitochondrial remodeling in HF patients or animal models, including the impairments in mitochondrial ultrastructure, oxidative metabolism, electron transport chain (ETC), phosphorylation apparatus, phosphotransfer system, and quality control. We also focus on molecular regulatory mechanisms upstream of mitochondria, including circulating factors (e.g., RAAS, TNF-α IL-6, IGF-1, GH, ghrelin, adiponectin, NO) and molecular signals within myocytes (e.g., PGC-1α, PPARs, AMPK, SIRT1/3, ROS, and MuRF1). Besides the therapies targeting the signaling pathways mentioned above, such as AdipoRon and elamipretide, we further summarize other potential pharmacological approaches like inhibitors of sodium-glucose cotransporter 2 (SGLT2) and dipeptidyl peptidase-4 (DPP-4), as well as some natural products, which may have the beneficial effects on improving the skeletal muscle mitochondrial function of HF. Targeting myocyte mitochondrial biogenesis, oxidative metabolism, oxidative phosphorylation, and reduction of oxidative stress injury are promising future opportunities for the prevention and management of skeletal muscle myopathy in HF.
Supraspinal melatonin MT2 receptor agonism alleviates pain via a neural circuit that recruits mu opioid receptors.
J Pineal Res
Luca Posa, Danilo De Gregorio, Martha Lopez-Canul +9 more
Melatonin, through its G protein-coupled receptor (GPCR) (MTNR1B gene) MT2 , is implicated in analgesia, but the relationship between MT2 receptors and the opioid system remains elusive. In a model of rodent neuropathic pain (spared nerve injured [SNI]), the selective melatonin MT2 agonist UCM924 reversed the allodynia (a pain response to a non-noxious stimulus), and this effect was nullified by the pharmacological blockade or genetic inactivation of the mu opioid receptor (MOR), but not the delta opioid receptor (DOR). Indeed, SNI MOR, but not DOR knockout mice, did not respond to the antiallodynic effects of the UCM924. Similarly, the nonselective opioid antagonist naloxone and the selective MOR antagonist D-Phe-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr-NH2 (CTOP) blocked the effects of UCM924 in SNI rats, but not the DOR antagonist naltrindole (NTI). Electrophysiological recordings in the rostral-ventromedial medulla (RVM) revealed that the typical reduction of the firing activity of pronociceptive ON-cells, and the enhancement of the firing of the antinociceptive OFF-cells, induced by the microinjection of the MT2 agonist UCM924 into the ventrolateral periaqueductal gray (vlPAG) were blocked by MOR, but not DOR, antagonism. Immunohistochemistry studies showed that MT2 receptors are expressed in both excitatory (CaMKIIα+ ) and inhibitory (GAD65+ ) neuronal cell bodies in the vlPAG (~2.16% total), but not RVM. Only 0.20% of vlPAG neurons coexpressed MOR and MT2 receptors. Finally, UCM924 treatment induced an increase in the enkephalin precursor gene (PENK) in the PAG of SNI mice. Collectively, the melatonin MT2 receptor agonism requires MORs to exert its antiallodynic effects, mostly through an interneuronal circuit involving MOR and MT2 receptors.
Distinct Impairments Characterizing Different ADNP Mutants Reveal Aberrant Cytoplasmic-Nuclear Crosstalk.
Cells
Maram Ganaiem, Gidon Karmon, Yanina Ivashko-Pachima +1 more
(1) Background: Activity-dependent neuroprotective protein (ADNP) is essential for neuronal structure and function. Multiple de novo pathological mutations in ADNP cause the autistic ADNP syndrome, and they have been further suggested to affect Alzheimer's disease progression in a somatic form. Here, we asked if different ADNP mutations produce specific neuronal-like phenotypes toward better understanding and personalized medicine. (2) Methods: We employed CRISPR/Cas9 genome editing in N1E-115 neuroblastoma cells to form neuron-like cell lines expressing ADNP mutant proteins conjugated to GFP. These new cell lines were characterized by quantitative morphology, immunocytochemistry and live cell imaging. (3) Results: Our novel cell lines, constitutively expressing GFP-ADNP p.Pro403 (p.Ser404* human orthologue) and GFP-ADNP p.Tyr718* (p.Tyr719* human orthologue), revealed new and distinct phenotypes. Increased neurite numbers (day 1, in culture) and increased neurite lengths upon differentiation (day 7, in culture) were linked with p.Pro403*. In contrast, p.Tyr718* decreased cell numbers (day 1). These discrete phenotypes were associated with an increased expression of both mutant proteins in the cytoplasm. Reduced nuclear/cytoplasmic boundaries were observed in the p.Tyr718* ADNP-mutant line, with this malformation being corrected by the ADNP-derived fragment drug candidate NAP. (4) Conclusions: Distinct impairments characterize different ADNP mutants and reveal aberrant cytoplasmic-nuclear crosstalk.