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[Role of endocrinological factors and metabolic processes in regulating life-span].
Orv Hetil
Tamás Halmos, Ilona Suba
Összefoglaló. Az emberek a lehető leghosszabb ideig akarnak élni, jó egészségben. Ha kiküszöbölnénk a kedvezőtlen külső körülményeket, a várható élettartam meghaladhatná a 100 évet. A 20. és 21. században a jóléti társadalmakban a várható élettartam jelentősen megnőtt, így Magyarországon is. Az áttekintett irodalom alapján megvizsgáltuk, hogy a genetika és az öröklődés mellett milyen endokrinológiai és metabolikus tényezők játszanak szerepet az élet meghosszabbításában. Megvizsgáltunk minden endogén tényezőt, amely pozitívan vagy negatívan befolyásolhatja az életkorral összefüggő betegségeket (Alzheimer-kór, szív- és érrendszeri betegségek, rák) és az élettartamot. Kiemeltük a hyperinsulinaemia, az inzulinrezisztencia, a metabolikus szindróma öregedést gyorsító hatását, az inzulinszerű növekedési hormon-1 ellentmondásos szerepét, valamint az élet meghosszabbításában részt vevő, újabban felfedezett peptideket, mint a klotho és a humanin. Ismertettük a mitochondriumok szerepét az élettartam meghatározásában, bemutattuk a mitohormesis folyamatát és annak stresszvédő funkcióját. Bemutattuk a rapamicin célszervét, az mTOR-t, amelynek gátlása meghosszabbítja az élettartamot, valamint a szirtuinokat. Kitértünk az autophagia folyamatára, és ismertettük a szenolitikumok szerepét az öregedésben. Az időskori autoimmunitás csökkenése hozzájárul az élettartam rövidüléséhez, utaltunk a thymus koordináló szerepére. Kiemeltük a bélmikrobiom fontos szerepét az élettartam szabályozásában. Hivatkoztunk a "centenáriusok" megfigyeléséből nyert humánadatokra. Megvizsgáltuk, milyen beavatkozási lehetőségek állnak rendelkezésre az egészségben tölthető élettartam meghosszabbításához. Az életmódbeli lehetőségek közül kiemeltük a kalóriabevitel-csökkentés és a testmozgás jótékony szerepét. Megvizsgáltuk egyes gyógyszerek feltételezett hatásait. Ezek közé tartozik a metformin, az akarbóz, a rezveratrol. E gyógyszerek mindegyikének hatása hasonló a kalóriamegszorításéhoz. Nincs olyan "csodaszer", amely igazoltan meghosszabbítja az élettartamot emberben. Egyes géneknek és génmutációknak jótékony hatásuk van, de ezt környezeti tényezők, betegségek, balesetek és más külső ártalmak módosíthatják. Kiemeljük az elhízás, az alacsony fokozatú gyulladás és az inzulinrezisztencia öregedésre gyakorolt gyorsító hatását. A metabolikus szindróma elterjedtsége miatt ez jelentős népegészségügyi kockázatot jelent. Az inzulin, a növekedési hormon és az inzulinszerű növekedési faktorok hatásainak értékelése továbbra is ellentmondásos. Az egészséges, szellemileg és fizikailag aktív életmód, a kalóriacsökkentés mindenképpen előnyös. Az életet meghosszabbító szerek értékelése még vitatott. Orv Hetil. 2021; 162(33): 1318-1327. Summary. People want to live as long as possible in good health. If we eliminate the unfavorable external conditions, the life expectancy could exceed 100 years. In the 20th and 21th centuries, life expectancy in welfare societies increased significantly, including in Hungary. Based on the reviewed literature, we examined what endocrinological and metabolic factors play a role in prolonging life in addition to genetics and inheritance. We examined all endogenous factors that can positively or negatively affect age-related diseases (Alzheimer's disease, cardiovascular disease, cancer) and longevity. We highlighted the aging effects of hyperinsulinemia, insulin resistance, metabolic syndrome, the controversial role of insulin-like growth factor-1, and more recently discovered peptides involved in prolonging lifespan, such as klotho and humanin. We described the role of mitochondria in determining longevity, we demonstrated the process of mitohormesis and its stress-protective function. We presented the target organ of rapamycin, mTOR, the inhibition of which prolongs lifespan, as well as sirtuins. We covered the process of autophagy and described the role of senolytics in aging. The decrease in autoimmunity in old age contributes to the shortening of life expectancy, we referred to the coordinating role of the thymus. We highlighted the important role of intestinal microbiome in the regulation of longevity. We referred to human data obtained from observations on "centenarians". We examined what intervention options are available to prolong healthy life expectancy. Among the lifestyle options, we highlighted the beneficial role of calorie reduction and exercise. We examined the putative beneficial effects of some drugs. These include metformin, acarbose, resveratrol. The effect of each of these drugs is similar to calorie restriction. There is no "miracle cure" that has been shown to prolong life-span in humans. Some genes and gene mutations have beneficial effects, but this can be modified by environmental factors, diseases, accidents, and other external harms. We highlight the accelerating effects of obesity, low-grade inflammation, and insulin resistance on aging. Due to the prevalence of metabolic syndrome, this poses a significant risk to public health. The assessment of the effects of insulin, growth hormone, and insulin-like growth factors remains controversial. A healthy, mentally and physically active lifestyle, calorie reduction is definitely beneficial. The evaluation of life-prolonging agents is still controversial. Orv Hetil. 2021; 162(33): 1318-1327.
Evolution of Neuroendocrine Tumor Therapy.
Surg Oncol Clin N Am
Thomas M O'Dorisio, Alan G Harris, M Sue O'Dorisio
To better understand developments in treatment of neuroendocrine tumors of the gastroenteropancreatic system, and the pivotal roles of native somatostatin and its long-acting analogues play in normal peptide regulation and neuropeptide excess associated with neuroendocrine tumors (NETs), this article delineates and defines distinct eras in the history and discovery of gastrointestinal endocrinology. We highlight the collaboration between academia and industry in basic science and the clinical research that advanced Lu-177-DOTATATE to approval as standard of care therapy for low-grade NETs. Examples of new radioisotopes and therapy compounds currently in development for diagnosis and therapy for high-grade NETs are also discussed.
Tesamorelin improves fat quality independent of changes in fat quantity.
AIDS
Jordan E Lake, Kristen La, Kristine M Erlandson +11 more
Fat quality and quantity may affect health similarly or differently. Fat quality can be assessed by measuring fat density on CT scan (greater density = smaller, higher quality adipocytes). We assessed the effects of tesamorelin, a growth hormone-releasing hormone analogue that reduces visceral fat (VAT) quantity in some people living with HIV (PWH), on fat density.
A thermosensitive, reactive oxygen species-responsive, MR409-encapsulated hydrogel ameliorates disc degeneration in rats by inhibiting the secretory autophagy pathway.
Theranostics
Qiangqiang Zheng, Haotian Shen, Zongrui Tong +8 more
Lumbar disc degeneration is a common cause of chronic low back pain and an important contributor to various degenerative lumbar spinal disorders. However, currently there is currently no effective therapeutic strategy for treating disc degeneration. The pro-inflammatory cytokine interleukin-1β (IL-1β) mediates disc degeneration by inducing apoptotic death of nucleus pulposus (NP) cells and degradation of the NP extracellular matrix. Here, we confirmed that extracellular secretion of IL-1β via secretory autophagy contributes to disc degeneration, and demonstrate that a thermosensitive reactive oxygen species (ROS)-responsive hydrogel loaded with a synthetic growth hormone-releasing hormone analog (MR409) can protect against needle puncture-induced disc degeneration in rats. Methods: The expression levels of proteins related to secretory autophagy such as tripartite motif-containing 16 (TRIM16) and microtubule-associated protein light chain 3B (LC3B) were examined in human and rat disc tissues by histology and immunofluorescence. The effects of TRIM16 expression level on IL-1β secretion were examined in THP-1 cells transfected with TRIM16 plasmid or siRNA using ELISA, immunofluorescence, and immunoblotting. The in vitro effects of MR409 on IL-1β were examined in THP-1 cells and primary rat NP cells using ELISA, immunofluorescence, immunoblotting, and qRT-PCR. Further, MR409 was subcutaneously administered to aged mice to test its efficacy against disc degeneration using immunofluorescence, X-ray, micro-CT, and histology. To achieve controllable MR409 release for intradiscal use, MR409 was encapsulated in an injectable ROS-responsive thermosensitive hydrogel. Viscosity, rheological properties, release profile, and biocompatibility were evaluated. Thereafter, therapeutic efficacy was assessed in a needle puncture-induced rat model of disc degeneration at 8 and 12 weeks post-operation using X-ray, magnetic resonance (MR) imaging, histological analysis, and immunofluorescence. Results: Secretory autophagy-related proteins TRIM16 and LC3B were robustly upregulated in degenerated discs of both human and rat. Moreover, while upregulation of TRIM16 facilitated, and knockdown of TRIM16 suppressed, secretory autophagy-mediated IL-1β secretion from THP-1 cells under oxidative stress, MR409 inhibited ROS-induced secretory autophagy and IL-1β secretion by THP-1 cells as well as IL-1β-induced pro-inflammatory and pro-catabolic effects in rat NP cells. Daily subcutaneous injection of MR409 inhibited secretory autophagy and ameliorated age-related disc degeneration in mice. The newly developed ROS-responsive MR409-encapsulated hydrogel provided a reliable delivery system for controlled MR409 release, and intradiscal application effectively suppressed secretory autophagy and needle puncture-induced disc degeneration in rats. Conclusion: Secretory autophagy and associated IL-1β secretion contribute to the pathogenesis of disc degeneration, and MR409 can effectively inhibit this pathway. The ROS-responsive thermosensitive hydrogel encapsulated with MR409 is a potentially efficacious treatment for disc degeneration.
Ghrelin Signaling: GOAT and GHS-R1a Take a LEAP in Complexity.
Trends Endocrinol Metab
Alfonso Abizaid, James L Hougland
Ghrelin and the growth hormone secretagogue receptor 1a (GHS-R1a) are important targets for disorders related to energy balance and metabolic regulation. Pharmacological control of ghrelin signaling is a promising avenue to address health issues involving appetite, weight gain, obesity, and related metabolic disorders, and may be an option for patients suffering from wasting conditions like cachexia. In this review, we summarize recent developments in the biochemistry of ghrelin and GHS-R1a signaling. These include unravelling the enzymatic transformations that generate active ghrelin and the discovery of multiple proteins that interact with ghrelin and GHS-R1a to regulate signaling. Furthermore, we propose that harnessing these processes will lead to highly selective treatments to address obesity, diabetes, and other metabolism-linked disorders.
The human hypothalamic kisspeptin system: Functional neuroanatomy and clinical perspectives.
Handb Clin Neurol
Erik Hrabovszky, Szabolcs Takács, Éva Rumpler +1 more
In mammals, kisspeptin neurons are the key components of the hypothalamic neuronal networks that regulate the onset of puberty, account for the pulsatile secretion of gonadotropin-releasing hormone (GnRH) and mediate negative and positive estrogen feedback signals to GnRH neurons. Being directly connected anatomically and functionally to the hypophysiotropic GnRH system, the major kisspeptin cell groups of the preoptic area/rostral hypothalamus and the arcuate (or infundibular) nucleus, respectively, are ideally positioned to serve as key nodes which integrate various types of environmental, endocrine, and metabolic signals that can influence fertility. This chapter provides an overview of the current state of knowledge on the anatomy, functions, and plasticity of brain kisspeptin systems based on the wide literature available from different laboratory and domestic species. Then, the species-specific features of human hypothalamic kisspeptin neurons are described, covering their topography, morphology, unique neuropeptide content, plasticity, and connectivity to hypophysiotropic GnRH neurons. Some newly emerging roles of central kisspeptin signaling in behavior and finally, clinical perspectives, are discussed.
Sex differences of oxytocin and vasopressin in social behaviors.
Handb Clin Neurol
Qiaoqiao Lu, Shaohua Hu
The neuropeptides oxytocin (OT) and vasopressin (VP) are known to mediate social cognition and behaviors in a sex-dependent manner. This chapter reviews the sex-dependent influence of OT and VP on social behaviors, focusing on (1) partner preference and sexual orientation, (2) memory modulation, (3) emotion regulation, and (4) trust-related behaviors. Most studies suggest that OT promotes familiar (opposite-sex) partner preference, strengthens memory, relieves anxiety, and increases trust. However, VP-regulated social cognition has been studied less than OT. VP facilitates familiar (opposite-sex) partner preference, enhances memory, induces anxiety, and influences happiness/anger perception. Detailed sex differences of these effects are reviewed. There is a male preponderance in the use of animal models and many study results are too complex to draw firm conclusions. Clarifying the complex interplay between the OT/VP system and sex hormones in the regulation of social behaviors is needed.
Eugenol-piperine loaded polyhydroxy butyrate/polyethylene glycol nanocomposite-induced apoptosis and cell death in nasopharyngeal cancer (C666-1) cells through the inhibition of the PI3K/AKT/mTOR signaling pathway.
J Biochem Mol Toxicol
Xiaopeng Sun, Vishnu Priya Veeraraghavan, Krishna Mohan Surapaneni +5 more
Nasopharyngeal cancer is a malignancy developing from the nasopharynx epithelium due to smoking and nitrosamine-containing foods. Nasopharyngeal cancer is highly endemic to Southeast Asia. Eugenol and piperine have shown many anticancer activities on numerous cancer types, like colon, lung, liver, and breast cancer. In this study, we amalgamated eugenol and piperine loaded with a polyhydroxy butyrate/polyethylene glycol nanocomposite (Eu-Pi/PHB-PEG-NC) for better anticancer results against nasopharyngeal cancer (C666-1) cells. In the current study, nasopharyngeal cancer cell lines C666-1 were utilized to appraise the cytotoxic potential of Eug-Pip-PEG-NC on cell propagation, programmed cell death, and relocation. Eu-Pi/PHB-PEG-NC inhibits cellular proliferation on C666-1 cells in a dose-dependent manner, and when compared with 20 µg/ml, 15 µg/ml of loaded mixture evidently restrained the passage aptitude of C666-1 cells, this was attended with a downregulated expression of mitochondrial membrane potential. Treatment with 15 µg/ml Eu-Pi/PHB-PEG-NC suggestively amplified cell apoptosis in the C666-1 cells. Furthermore, its cleaved caspase-3, 8, and 9 and Bax gene expression was augmented and Bcl-2 gene expression was diminished after Eu-Pi/PHB-PEG-NC treatment. Additionally, our data established that the collective effect of Eu-Pi/PHB-PEG-NC loaded micelles inhibited the expansion of C666-1 cells augmented apoptosis connected with the intrusion of PI3K/Akt/mTOR signaling pathway.
Brain Protein Expression Profile Confirms the Protective Effect of the ACTH(4-7)PGP Peptide (Semax) in a Rat Model of Cerebral Ischemia-Reperfusion.
Int J Mol Sci
Olga Yu Sudarkina, Ivan B Filippenkov, Vasily V Stavchansky +10 more
The Semax (Met-Glu-His-Phe-Pro-Gly-Pro) peptide is a synthetic melanocortin derivative that is used in the treatment of ischemic stroke. Previously, studies of the molecular mechanisms underlying the actions of Semax using models of cerebral ischemia in rats showed that the peptide enhanced the transcription of neurotrophins and their receptors and modulated the expression of genes involved in the immune response. A genome-wide RNA-Seq analysis revealed that, in the rat transient middle cerebral artery occlusion (tMCAO) model, Semax suppressed the expression of inflammatory genes and activated the expression of neurotransmitter genes. Here, we aimed to evaluate the effect of Semax in this model via the brain expression profiling of key proteins involved in inflammation and cell death processes (MMP-9, c-Fos, and JNK), as well as neuroprotection and recovery (CREB) in stroke. At 24 h after tMCAO, we observed the upregulation of active CREB in subcortical structures, including the focus of the ischemic damage; downregulation of MMP-9 and c-Fos in the adjacent frontoparietal cortex; and downregulation of active JNK in both tissues under the action of Semax. Moreover, a regulatory network was constructed. In conclusion, the suppression of inflammatory and cell death processes and the activation of recovery may contribute to the neuroprotective action of Semax at both the transcriptome and protein levels.
Hormonal Regulation of Oligodendrogenesis II: Implications for Myelin Repair.
Biomolecules
Jocelyn M Breton, Kimberly L P Long, Matthew K Barraza +2 more
Alterations in myelin, the protective and insulating sheath surrounding axons, affect brain function, as is evident in demyelinating diseases where the loss of myelin leads to cognitive and motor dysfunction. Recent evidence suggests that changes in myelination, including both hyper- and hypo-myelination, may also play a role in numerous neurological and psychiatric diseases. Protecting myelin and promoting remyelination is thus crucial for a wide range of disorders. Oligodendrocytes (OLs) are the cells that generate myelin, and oligodendrogenesis, the creation of new OLs, continues throughout life and is necessary for myelin plasticity and remyelination. Understanding the regulation of oligodendrogenesis and myelin plasticity within disease contexts is, therefore, critical for the development of novel therapeutic targets. In our companion manuscript, we review literature demonstrating that multiple hormone classes are involved in the regulation of oligodendrogenesis under physiological conditions. The majority of hormones enhance oligodendrogenesis, increasing oligodendrocyte precursor cell differentiation and inducing maturation and myelin production in OLs. Thus, hormonal treatments present a promising route to promote remyelination. Here, we review the literature on hormonal regulation of oligodendrogenesis within the context of disorders. We focus on steroid hormones, including glucocorticoids and sex hormones, peptide hormones such as insulin-like growth factor 1, and thyroid hormones. For each hormone, we describe whether they aid in OL survival, differentiation, or remyelination, and we discuss their mechanisms of action, if known. Several of these hormones have yielded promising results in both animal models and in human conditions; however, a better understanding of hormonal effects, interactions, and their mechanisms will ultimately lead to more targeted therapeutics for myelin repair.
The Mesencephalic Trigeminal Nucleus Controls Food Intake and Body Weight via Hindbrain POMC Projections.
Nutrients
Samantha M Fortin, Jack Chen, Harvey J Grill +1 more
The mesencephalic trigeminal nucleus (Mes5) processes oral sensory-motor information, but its role in the control of energy balance remains unexplored. Here, using fluorescent in situ hybridization, we show that the Mes5 expresses the melanocortin-4 receptor. Consistent with MC4R activation in other areas of the brain, we found that Mes5 microinjection of the MC4R agonist melanotan-II (MTII) suppresses food intake and body weight in the mouse. Furthermore, NTS POMC-projecting neurons to the Mes5 can be chemogenetically activated to drive a suppression in food intake. Taken together, these findings highlight the Mes5 as a novel target of melanocortinergic control of food intake and body weight regulation, although elucidating the endogenous role of this circuit requires future study. While we observed the sufficiency of Mes5 MC4Rs for food intake and body weight suppression, these receptors do not appear to be necessary for food intake or body weight control. Collectively, the data presented here support the functional relevance of the NTS POMC to Mes5 projection pathway as a novel circuit that can be targeted to modulate food intake and body weight.
The role of oxytocin and vasopressin dysfunction in cognitive impairment and mental disorders.
Neuropeptides
Olga Abramova, Yana Zorkina, Valeria Ushakova +3 more
Oxytocin (OXT) and arginine-vasopressin (AVP) are structurally homologous peptide hormones synthesized in the hypothalamus. Nowadays, the role of OXT and AVP in the regulation of social behaviour and emotions is generally known. However, recent researches indicate that peptides also participate in cognitive functioning. This review presents the evidence that the OXT/AVP systems are involved in the formation of social, working, spatial and episodic memory, mediated by such brain structures as the hippocampal CA2 and CA3 regions, amygdala and prefrontal cortex. Some data have demonstrated that the OXT receptor's polymorphisms are associated with impaired memory in humans, and OXT knockout in mice is connected with memory deficit. Additionally, OXT and AVP are involved in mental disorders' progression. Stress-induced imbalance of the OXT/AVP systems leads to an increased risk of various mental disorders, including depression, schizophrenia, and autism. At the same time, cognitive deficits are observed in stress and mental disorders, and perhaps peptide hormones play a part in this. The final part of the review describes possible therapeutic strategies for the use of OXT and AVP for treatment of various mental disorders.
GDF11 Alleviates Pathological Myocardial Remodeling in Diabetic Cardiomyopathy Through SIRT1-Dependent Regulation of Oxidative Stress and Apoptosis.
Front Cell Dev Biol
Han-Zhao Zhu, Li-Yun Zhang, Meng-En Zhai +14 more
Growth differentiation factor 11 (GDF11) is a member of the transforming growth factor β superfamily that alleviates cardiac hypertrophy, myocardial infarction, and vascular injury by regulating oxidative stress, inflammation, and cell survival. However, the roles and underlying mechanisms of GDF11 in diabetic cardiomyopathy (DCM) remain largely unknown. In this study, we sought to determine whether GDF11 could prevent DCM. After establishing a mouse model of diabetes by administering a high-fat diet and streptozotocin, intramyocardial injection of an adeno-associated virus was used to achieve myocardium-specific GDF11 overexpression. GDF11 remarkably improved cardiac dysfunction and interstitial fibrosis by reducing the levels of reactive oxygen species and protecting against cardiomyocyte loss. Mechanistically, decreased sirtuin 1 (SIRT1) expression and activity were observed in diabetic mice, which was significantly increased after GDF11 overexpression. To further explore how SIRT1 mediates the role of GDF11, the selective inhibitor EX527 was used to block SIRT1 signaling pathway, which abolished the protective effects of GDF11 against DCM. In vitro studies confirmed that GDF11 protected against H9c2 cell injury in high glucose and palmitate by attenuating oxidative injury and apoptosis, and these effects were eliminated by SIRT1 depletion. Our results demonstrate for the first time that GDF11 protects against DCM by regulating SIRT1 signaling pathway.
Recombinant Human Elafin Ameliorates Chronic Hyperoxia-Induced Lung Injury by Inhibiting Nuclear Factor-Kappa B Signaling in Neonatal Mice.
J Interferon Cytokine Res
Kexin Li, Fengmei Zhang, Li Wei +5 more
The study aimed to investigate whether recombinant human elafin can prevent hyperoxia-induced pulmonary inflammation in newborn mice, and to explore the mechanism underlying the inhibitory effects of elafin on nuclear factor-kappa B (NF-κB) signaling pathway. Neonatal C57BL/6J mice were exposed to 85% O2 for 1, 3, 7, 14, or 21 days. Then, elafin was administered daily for 20 days through intraperitoneal injection. After treatment, morphometric analysis, quantitative real-time polymerase chain reaction, terminal deoxynucleotidyl transferase dUTP nick end labeling staining, and Western blotting were carried out to determine the key markers involved in inflammatory process and the potential signaling pathways in hyperoxia-exposed newborn mice treated with elafin. In neonatal bronchopulmonary dysplasia (BPD) mice, hyperoxia induced apoptosis by increasing Bcl-2-associated X protein expression, and triggered inflammation by upregulating the expression levels of interleukin (IL)-1β, IL-6, IL-8, and tumor necrosis factor-α. Moreover, hyperoxia activated NF-κB signaling pathway by promoting the nuclear translocation of p65 in lung tissue. However, all these changes could be inhibited or reversed by elafin at least partially. Elafin reduced apoptosis, suppressed inflammation cytokines, and improved NF-κB p65 nuclear accumulation in hyperoxia-exposed neonatal mice, indicating that this recombinant protein can serve as a novel target for the treatment of BPD.
Thymosin β4 dynamics during chicken enteroid development.
Mol Cell Biochem
Mohan Acharya, Rohana Liyanage, Anamika Gupta +4 more
The sheared avian intestinal villus-crypts exhibit high tendency to self-repair and develop enteroids in culture. Presuming that this transition process involves differential biomolecular changes, we employed matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF-MS) to find whether there were differences in the spectral profiles of sheared villi versus the enteroids, assessed in the mass range of 2-18 kDa. The results showed substantial differences in the intensities of the spectral peaks, one particularly corresponding to the mass of 4963 Da, which was significantly low in the sheared villus-crypts compared with the enteroids. Based on our previous results with other avian tissues and further molecular characterization by LC-ESI-IT-TOF-MS, and multiple reaction monitoring (MRM), the peak was identified to be thymosin β4 (Tβ4), a ubiquitously occurring regulatory peptide implicated in wound healing process. The identity of the peptide was further confirmed by immunohistochemistry which showed it to be present in a very low levels in the sheared villi but replete in the enteroids. Since Tβ4 sequesters G-actin preventing its polymerization to F-actin, we compared the changes in F-actin by its immunohistochemical localization that showed no significant differences between the sheared villi and enteroids. We propose that depletion of Tβ4 likely precedes villous reparation process. The possible mechanism for the differences in Tβ4 profile in relation to the healing of the villus-crypts to developing enteroids is discussed.
Hypothalamic reproductive neurons communicate through signal transduction to control reproduction.
Mol Cell Endocrinol
Emma K McIlwraith, Denise D Belsham
Gonadotropin-releasing hormone (GnRH) neurons in the hypothalamus coordinate fertility and puberty. In order to achieve successful reproductive capacity, they receive signals from the periphery and from other hypothalamic neurons that coordinate energy homeostasis. Hormones, such as estradiol, insulin, leptin, and adiponectin, act directly or indirectly on GnRH and its associated reproductive neurons. Nutrients like glucose and fatty acids can also affect reproductive neurons to signal nutrient availability. Additionally, acute and chronic inflammation is reported to detrimentally affect GnRH and kisspeptin expression. All of these cues activate signal transduction pathways within neurons that lead to the changes in GnRH neuronal function. The signalling pathways can also be dysregulated by endocrine disrupting chemicals, which impair fertility by misappropriating common signalling pathways. The complex mechanisms controlling the levels of GnRH during the reproductive cycle rely on a carefully orchestrated set of signal transduction events to regulate the positive and negative feedback arms of the hypothalamic-pituitary-gonadal axis. If these signalling events are dysregulated, this will result is a downregulatory event leading to hypogonadal hypogonadism with decreased or absent fertility. Therefore, an understanding of the mechanisms involved in distinct neuronal signalling could provide an advantage to inform therapeutic interventions for infertility and reproductive disorders.
Pericyte-secreted IGF2 promotes breast cancer brain metastasis formation.
Mol Oncol
Kinga Molnár, Ádám Mészáros, Csilla Fazakas +9 more
Brain metastases are life-threatening complications of triple-negative breast cancer, melanoma, and a few other tumor types. Poor outcome of cerebral secondary tumors largely depends on the microenvironment formed by cells of the neurovascular unit, among which pericytes are the least characterized. By using in vivo and in vitro techniques and human samples, here we show that pericytes play crucial role in the development of metastatic brain tumors by directly influencing key steps of the development of the disease. Brain pericytes had a prompt chemoattractant effect on breast cancer cells and established direct contacts with them. By secreting high amounts of extracellular matrix proteins, pericytes enhanced adhesion of both melanoma and triple-negative cancer cells, which might be particularly important in the exclusive perivascular growth of these tumor cells. In addition, pericytes secreted insulin-like growth factor 2 (IGF2), which had a very significant pro-proliferative effect on mammary carcinoma, but not on melanoma cells. By inhibiting IGF2 signaling using silencing or picropodophyllin (PPP), we could block the proliferation-increasing effect of pericytes on breast cancer cells. Administration of PPP (a blood-brain barrier-permeable substance) significantly decreased the size of brain tumors in mice inoculated with triple-negative breast cancer cells. Taken together, our results indicate that brain pericytes have significant pro-metastatic features, especially in breast cancer. Our study underlines the importance of targeting pericytes and the IGF axis as potential strategies in brain metastatic diseases.
Simultaneous targeting of oxidative stress and fibrosis reverses cardiomyopathy-induced ventricular remodelling and dysfunction.
Br J Pharmacol
Chao Wang, Tracey A Gaspari, Dorota Ferens +3 more
Oxidative stress and fibrosis are hallmarks of cardiomyopathy-induced heart failure yet are not effectively targeted by current frontline therapies. Here, the therapeutic effects of the anti-oxidant, N-acetylcysteine (NAC), were compared and combined with an acute heart failure drug with established anti-fibrotic effects, serelaxin (RLX), in a murine model of cardiomyopathy.
Thymosin‑β 4 induces angiogenesis in critical limb ischemia mice via regulating Notch/NF‑κB pathway.
Int J Mol Med
Shumin Lv, Hongwen Cai, Yifei Xu +3 more
Thymosin‑β 4 (Tβ4) has been reported to exert a pro‑angogenic effect on endothelial cells. However, little is known on the role and underlying mechanisms of Tβ4 on critical limb ischemia (CLI). The present study aimed therefore to investigate the mechanisms and pro‑angiogenic effects of Tβ4 in CLI mice. Tβ4 overexpression lentiviral vector was first transfected into HUVEC and CLI mice model, and inhibitors of Notch pathway (DAPT) and NF‑κB pathway (BMS) were also applied to HUVEC and CLI mice. Subsequently, MTT, tube formation and wound healing assays were used to determine the cell viability, angiogenesis and migratory ablity of HUVEC, respectively. Western blotting, reverse transcription, quantitative PCR, immunofluorescence and immunohistochemistry were used to detect the expression of the angiogenesis‑related factors angiopoietin‑2 (Ang2), TEK receptor tyrosine kinase 2 (tie2), vascular endothelial growth factor A (VEGFA), CD31 and α‑smooth muscle actin (α‑SMA) and the Notch/NF‑κB pathways‑related factors NOTCH1 intracellular domain (N1ICD), Notch receptor 3 (Notch3), NF‑κB and p65 in HUVEC or CLI mice muscle tissues. The results demonstrated that Tβ4 not only enhanced the cell viability, angiogenesis and migratory ability of HUVEC but also promoted the expression of Ang2, tie2, VEGFA, N1ICD, Notch3, NF‑κB, and phosphorylated (p)‑p65 in HUVEC. In addition, Tβ4 promoted the expression of CD31, α‑SMA Ang2, tie2, VEGFA, N1ICD and p‑p65 in CLI mice muscle tissues. Treatment with DAPT and BMS had opposite effects of Tβ4, whereas Tβ4 reversed the effect of DAPT and BMS. The findings from the present study suggested that Tβ4 may promote angiogenesis in CLI mice via regulation of Notch/NF‑κB pathways.
Targeting the TLR2 Receptor With a Novel Thymopentin-Derived Peptide Modulates Immune Responses.
Front Immunol
Xubiao Wei, Lulu Zhang, Rijun Zhang +9 more
The innate and adaptive immune systems act in concert to protect us from infectious agents and other harmful substances. As a state of temporary or permanent immune dysfunction, immunosuppression can make an organism more susceptible to infection, organ injury, and cancer due to damage to the immune system. It takes a long time to develop new immunomodulatory agents to prevent and treat immunosuppressive diseases, with slow progress. Toll-like receptor 2 (TLR2) agonists have been reported as potential immunomodulatory candidates due to their effective activation of immune responses. It has been demonstrated that thymopentin (TP5) could modulate immunity by binding to the TLR2 receptor. However, the fairly short half-life of TP5 greatly reduces its pharmacological potential for immunosuppression therapy. Although peptide cathelicidin 2 (CATH2) has a long half-life, it shows poor immunomodulatory activity and severe cytotoxicity, which seriously hampers its clinical development. Peptide hybridization is an effective approach for the design and engineering of novel functional peptides because hybrid peptides combine the advantages and benefits of various native peptides. In this study, to overcome all these challenges faced by the parental peptides, six hybrid peptides (CaTP, CbTP, CcTP, TPCa, TPCb, and TPCc) were designed by combining the full-length TP5 with different active fragments of CATH2. CbTP, the most potent TLR2 agonist among the six hybrid peptides, was effectively screened through in silico analysis and in vitro experiments. The CbTP peptide exhibited lower cytotoxicity than either CATH2 or TP5. Furthermore, the immunomodulatory effects of CbTP were confirmed in a CTX-immunosuppressed mouse model, which showed that CbTP has increased immunopotentiating activity and physiological stability compared to the parental peptides. CbTP successfully inhibited immunosuppression and weight loss, increased immune organ indices, and improved CD4+/CD8+ T lymphocyte subsets. In addition, CbTP significantly increased the production of the cytokine TNF-α and IL-6, and the immunoglobulins IgA, IgM, and IgG. The immunoenhancing effects of CbTP were attributed to its TLR2-binding activity, promoting the formation of the TLR2 cluster, the activation of the TLR2 receptor, and thus activation of the downstream MyD88-NF-кB signaling pathway.