Key subdomains of mesencephalic astrocyte-derived neurotrophic factor attenuate myocardial ischemia/reperfusion injury by JAK1/STAT1/NF-κB signaling pathway.

BACKGROUND: Myocardial ischemia/reperfusion (I/R) injury is a common pathological process in clinical practice. Developing effective therapeutic strategies to reduce or prevent this injury is crucial. The article aimed to investigate the role and mechanism of mesencephalic astrocyte-derived neurotrophic factor (MANF) and its key subdomains in modulating myocardial I/R-induced cardiomyocyte apoptosis. METHODS: MANF stable knockout cell line and MANF mutant overexpression plasmids were constructed. The effects of MANF and mutants on apoptosis and endoplasmic reticulum (ER) stress related proteins were evaluated in hypoxia/reoxygenation-induced HL-1 cardiomyocytes by western blot, immunofluorescence, Tunel and flow cytometry. Echocardiography, ELISA, TTC and Masson were used to observe the effects of recombinant MANF protein (rMANF) on cardiac function in myocardial I/R mice. RESULTS: This study observed increased expression of MANF in both myocardial infarction patients and I/R mice. MANF overexpression in cardiomyocytes decreased ER stress-induced apoptosis, while MANF knockout exacerbated it. rMANF improved cardiac function in I/R mice by reducing injury and inflammation. This study specifically demonstrates that mutations in the α-helix of MANF were more effective in reducing ER stress and cardiomyocyte apoptosis. Mechanistically, MANF and the α-helix mutant attenuated I/R injury by inhibiting the JAK1/STAT1/NF-κB signaling pathway in addition to reducing ER stress-induced apoptosis. CONCLUSION: These findings highlight MANF and its subdomains as critical regulators of myocardial I/R injury, offering promising therapeutic targets with significant clinical implications for I/R-related diseases.

Molecular Adaptations of BDNF/NT-4 Neurotrophic and Muscarinic Pathways in Ageing Neuromuscular Synapses.

Age-related conditions, such as sarcopenia, cause physical disabilities for an increasing section of society. At the neuromuscular junction, the postsynaptic-derived neurotrophic factors brain-derived neurotrophic factor (BDNF) and neurotrophin 4 (NT-4) have neuroprotective functions and contribute to the correct regulation of the exocytotic machinery. Similarly, presynaptic muscarinic signalling plays a fundamental modulatory function in this synapse. However, whether or not these signalling pathways are compromised in ageing neuromuscular system has not yet been analysed. The present study analyses, through Western blotting, the differences in expression and activation of the main key proteins of the BDNF/NT-4 and muscarinic pathways related to neurotransmission in young versus ageing Extensor digitorum longus (EDL) rat muscles. The main results show an imbalance in several sections of these pathways: (i) a change in the stoichiometry of BDNF/NT-4, (ii) an imbalance of Tropomyosin-related kinase B receptor (TrkB)-FL/TrkB-T1 and neurotrophic receptor p 75 (p75NTR), (iii) no changes in the cytosol/membrane distribution of phosphorylated downstream protein kinase C (PKC)ßI and PKCε, (iv) a reduction in the M2-subtype muscarinic receptor and P/Q-subtype voltage-gated calcium channel, (v) an imbalance of phosphorylated mammalian uncoordinated-18-1 (Munc18-1) (S313) and synaptosomal-associated protein 25 (SNAP-25) (S187), and (vi) normal levels of molecules related to the management of acetylcholine (Ach). Based on this descriptive analysis, we hypothesise that these pathways can be adjusted to ensure neurotransmission rather than undergoing negative alterations caused by ageing. However, further studies are needed to assess this hypothetical suggestion. Our results contribute to the understanding of some previously described neuromuscular functional age-related impairments. Strategies to promote these signalling pathways could improve the neuromuscular physiology and quality of life of older people.

Neurotrophins and Their Receptors: BDNF's Role in GABAergic Neurodevelopment and Disease.

Neurotrophins and their receptors are distinctly expressed during brain development and play crucial roles in the formation, survival, and function of neurons in the nervous system. Among these molecules, brain-derived neurotrophic factor (BDNF) has garnered significant attention due to its involvement in regulating GABAergic system development and function. In this review, we summarize and compare the expression patterns and roles of neurotrophins and their receptors in both the developing and adult brains of rodents, macaques, and humans. Then, we focus on the implications of BDNF in the development and function of GABAergic neurons from the cortex and the striatum, as both the presence of BDNF single nucleotide polymorphisms and disruptions in BDNF levels alter the excitatory/inhibitory balance in the brain. This imbalance has different implications in the pathogenesis of neurodevelopmental diseases like autism spectrum disorder (ASD), Rett syndrome (RTT), and schizophrenia (SCZ). Altogether, evidence shows that neurotrophins, especially BDNF, are essential for the development, maintenance, and function of the brain, and disruptions in their expression or signaling are common mechanisms in the pathophysiology of brain diseases.

The effect of salidroside in promoting endogenous neural regeneration after cerebral ischemia/reperfusion involves notch signaling pathway and neurotrophic factors.

BACKGROUND: Salidroside is the major bioactive and pharmacological active substance in Rhodiola rosea L. It has been reported to have neuroprotective effects on cerebral ischemia/reperfusion (I/R). However, whether salidroside can enhance neural regeneration after cerebral I/R is still unknown. This study investigated the effects of salidroside on the endogenous neural regeneration after cerebral I/R and the related mechanism. METHODS: Focal cerebral I/R was induced in rats by transient middle cerebral artery occlusion/reperfusion (MCAO/R). The rats were intraperitoneally treated salidroside once daily for 7 consecutive days. Neurobehavioral assessments were performed at 3 days and 7 days after the injury. TTC staining was performed to assess cerebral infarct volume. To evaluate the survival of neurons, immunohistochemical staining of Neuronal Nuclei (NeuN) in the ischemic hemisphere were conducted. Also, immunofluorescence double or triple staining of the biomarkers of proliferating neural progenitor cells in Subventricular Zone (SVZ) and striatum of the ischemia hemisphere were performed to investigate the neurogenesis. Furthermore, reverse transcription-polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA) were used to detect the expression of neurotrophic factors (NTFs) brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF). Expression of Notch1 and its target molecular Hes1 were also analyzed by western-blotting and RT-PCR. RESULTS: Salidroside treatment ameliorated I/R induced neurobehavioral impairment, and reduced infarct volume. Salidroside also restored NeuN positive cells loss after I/R injury. Cerebral I/R injury significantly increased the expression of 5-Bromo-2'-Deoxyuridine (BrdU) and doublecotin (DCX), elevated the number of BrdU/Nestin/DCX triple-labeled cells in SVZ, and BrdU/Nestin/glial fibrillary acidic protein (GFAP) triple-labeled cells in striatum. Salidroside treatment further promoted the proliferation of BrdU/DCX labeled neuroblasts and BrdU/Nestin/GFAP labeled reactive astrocytes. Furthermore, salidroside elevated the mRNA expression and protein concentration of BDNF and NGF in ischemia periphery area, as well. Mechanistically, salidroside elevated Notch1/Hes1 mRNA expression in SVZ. The protein levels of them were also increased after salidroside administration. CONCLUSIONS: Salidroside enhances the endogenous neural regeneration after cerebral I/R. The mechanism of the effect may involve the regulation of BDNF/NGF and Notch signaling pathway.

Vitamin D ameliorates memory function in association with reducing senescence and upregulating neurotrophin mRNA expression in transient global cerebral ischemic injury model in rats.

INTRODUCTION: Ischaemic stroke induces oxidative stress, mitochondrial damage, inflammation and senescence and the decrease of cognitive function. Vitamin D is a fat-soluble vitamin that has a neuroprotective effect to repair the function of the nervous system. The aim of this study is to investigate the effect of vitamin D on memory function, p16, p21 (senescence), and nerve growth factor (NGF) mRNA expression on the hippocampus after transient global cerebral ischemic. MATERIALS AND METHODS: The study was designed as quasiexperimental with a control group that only received posttests. We performed in vivo study with an induction bilateral common carotid artery occlusion (BCCAO) model and vitamin D injection for 10 days. A total of 24 rats were divided into four groups (n = 6): Sham operation (SO [control]), BCCAO (transient global cerebral ischemic model not given vitamin D), VD1 (BCCAO + vitamin D 0.125 µg/kgBW), and VD2 (BCCAO + vitamin D 0.5 µg/kgBW). The spatial memory function was tested with the Morris water maze. We performed immunohistochemistry to localise p16 expression. p16, p21 and NGF mRNA expression were assessed by reverse transcriptase (RT-PCR) method. RESULTS: The vitamin D treatment group required shorter mileage to find the platform and probe test. The total time spent was longer in the target quadrant than in non-target. The Vitamin D-treated group had lower p16 and p21 mRNA expression and higher NGF mRNA expression than the BCCAO group. Immunostaining showed p16 signal in the pyramidal cell of CA1 area in the BCCAO group. CONCLUSION: Vitamin D repairs memory function, senescence expression was lower and NGF was higher in the BCCAO model.

Pigment Epithelium-Derived Factor Binding to VEGFR-1 (Flt-1) Increases the Survival of Retinal Neurons.

Purpose: The purpose of this study was to examine possible involvement of vascular endothelial growth factor (VEGF) receptor (VEGFR)-1/Flt-1 in pigment epithelium-derived factor (PEDF)-promoted survival of retinal neurons. Methods: Survival of growth factor-deprived retinal ganglion cells (RGCs) and R28 cells and activation of ERK-1/-2 MAP kinases were assessed in the presence of PEDF, placental growth factor (PlGF), and VEGF using cell cultures, viability assays and quantitation of ERK-1/-2 phosphorylation. VEGFR-1/Flt-1 expression was determined using quantitative PCR (qPCR) and Western blotting. VEGFR-1/Flt-1 was knocked down in R28 cells by small interfering RNA (siRNA). Binding of a PEDF-IgG Fc fusion protein (PEDF-Fc) to retinal neurons, immobilized VEGFR-1/Flt-1 and VEGFR-1/Flt-1-derived peptides was studied using binding assays and peptide scanning. Results: PEDF in combination with PlGF stimulated increased cell survival and ERK-1/-2 MAP kinase activation compared to effects of either factor alone. VEGFR-1/Flt-1 expression in RGCs and R28 cells was significantly upregulated by hypoxia, VEGF, and PEDF. VEGFR-1/Flt-1 ligands (VEGF and PlGF) or soluble VEGFR-1 (sflt-1) competed with PEDF-Fc for binding to R28 cells. Depleting R28 cells of VEGFR-1/Flt-1 resulted in reduced PEDF-Fc binding when comparing VEGFR-1/Flt-1 siRNA- and control siRNA-treated cells. PEDF-Fc interacted with immobilized sflt-1, which was specifically blocked by VEGF and PlGF. PEDF-Fc binding sites were mapped to VEGFR-1/Flt-1 extracellular domains D3 and D4. Peptides corresponding to D3 and D4 specifically inhibited PEDF-Fc binding to R28 cells. These peptides and sflt-1 significantly inhibited PEDF-promoted survival of R28 cells. Conclusions: These results suggest that PEDF can target VEGFR-1/Flt-1 and this interaction plays a significant role in PEDF-mediated neuroprotection in the retina.

The Role of Astrocytes in Parkinson's Disease : Astrocytes in Parkinson's Disease.

Parkinson's disease (PD) is a neurodegenerative disorder with a complex and multifactorial pathogenesis. This chapter delves into the critical role of astrocytes in PD. Once viewed as supporting cells in the central nervous system, astrocytes have emerged as key players in both maintaining neuronal health and contributing to neurodegeneration in PD. Their functions play a dual role in the progression of PD, ranging from protective functions like secretion of neurotrophic factors and clearance of α-synuclein to detrimental functions like promotion of neuroinflammation. This chapter is structured into three primary sections: the morphological and functional organization of astrocytes, astrocytic calcium signaling, and the role of astrocyte heterogeneity in PD. We provide a detailed exploration of astrocytic organelles, bidirectional astrocyte-neuron interactions, and the impact of astrocytic secretions such as antioxidant molecules and neurotrophic factors. Furthermore, we discuss the influence of astrocytes on non-neuronal cells, including interactions with microglia and the blood-brain barrier (BBB). By examining the multifaceted roles of astrocytes, in this chapter, we aim to bridge basic astrocyte biology with the clinical complexities of PD, offering insights into novel therapeutic strategies. The inclusion of astrocyte biology in our broader research approach will aid in the development of more effective treatment strategies for PD.

Unfolded protein response markers Grp78 and eIF2alpha are upregulated with increasing alpha-synuclein levels in Lewy body disease.

AIMS: Endoplasmic reticulum stress followed by the unfolded protein response is one of the cellular mechanisms contributing to the progression of α-synuclein pathology in Parkinson's disease and other Lewy body diseases. We aimed to investigate the activation of endoplasmic reticulum stress and its correlation with α-synuclein pathology in human post-mortem brain tissue. METHODS: We analysed brain tissue from 45 subjects-14 symptomatic patients with Lewy body disease, 19 subjects with incidental Lewy body disease, and 12 healthy controls. The analysed brain regions included the medulla, pons, midbrain, striatum, amygdala and entorhinal, temporal, frontal and occipital cortex. We analysed activation of endoplasmic reticulum stress via levels of the unfolded protein response-related proteins (Grp78, eIF2α) and endoplasmic reticulum stress-regulating neurotrophic factors (MANF, CDNF). RESULTS: We showed that regional levels of two endoplasmic reticulum-localised neurotrophic factors, MANF and CDNF, did not change in response to accumulating α-synuclein pathology. The concentration of MANF negatively correlated with age in specific regions. eIF2α was upregulated in the striatum of Lewy body disease patients and correlated with increased α-synuclein levels. We found the upregulation of chaperone Grp78 in the amygdala and nigral dopaminergic neurons of Lewy body disease patients. Grp78 levels in the amygdala strongly correlated with soluble α-synuclein levels. CONCLUSIONS: Our data suggest a strong but regionally specific change in Grp78 and eIF2α levels, which positively correlates with soluble α-synuclein levels. Additionally, MANF levels decreased in dopaminergic neurons in the substantia nigra. Our research suggests that endoplasmic reticulum stress activation is not associated with Lewy pathology but rather with soluble α-synuclein concentration and disease progression.

Epimedium flavonoids improve cerebral white matter lesions by inhibiting neuroinflammation and activating neurotrophic factor signal pathways in spontaneously hypertensive rats.

Cerebral small vessel disease (CSVD) is one of the most common nervous system diseases. Hypertension and neuroinflammation are considered important risk factors for the development of CSVD and white matter (WM) lesions. We used the spontaneously hypertensive rat (SHR) as a model of early-onset CSVD and administered epimedium flavonoids (EF) for three months. The learning and memorization abilities were tested by new object recognition test. The pathological changes of WM were assessed using magnetic resonance imaging, transmission electron microscopy (TEM), Luxol fast blue and Black Gold staining. Oligodendrocytes (OLs) and myelin basic protein were detected by immunohistochemistry. The ultrastructure of the tight junctions was examined using TEM. Microglia and astrocytes were detected by immunofluorescence. RNA-seq was performed on the corpus callosum of rats. The results revealed that EF could significantly improve the learning and memory impairments in SHR, alleviate the injury and demyelination of WM nerve fibers, promote the differentiation of oligodendrocyte precursor cells (OPCs) into mature OLs, inhibit the activation of microglia and astrocytes, inhibit the expression of p38 MAPK/NF-κB p65/NLRP3 and inflammatory cytokines, and increase the expression of tight-junction related proteins ZO-1, occludin, and claudin-5. RNA-seq analysis showed that the neurotrophin signaling pathway played an important role in the disease. RT-qPCR and WB results showed that EF could regulate the expression of nerve growth factor and brain-derived neurotrophic factor and their downstream related proteins in the neurotrophin signaling pathway, which might explain the potential mechanism of EF's effects on the cognitive impairment and WM damage caused by hypertension.

Delivery of CDNF by AAV-mediated gene transfer protects dopamine neurons and regulates ER stress and inflammation in an acute MPTP mouse model of Parkinson's disease.

Cerebral dopamine neurotrophic factor (CDNF) and its close structural relative, mesencephalic astrocyte-derived neurotrophic factor (MANF), are proteins with neurotrophic properties. CDNF protects and restores the function of dopamine (DA) neurons in rodent and non-human primate (NHP) toxin models of Parkinson's disease (PD) and therefore shows promise as a drug candidate for disease-modifying treatment of PD. Moreover, CDNF was found to be safe and to have some therapeutic effects on PD patients in phase 1/2 clinical trials. However, the mechanism underlying the neurotrophic activity of CDNF is unknown. In this study, we delivered human CDNF (hCDNF) to the brain using an adeno-associated viral (AAV) vector and demonstrated the neurotrophic effect of AAV-hCDNF in an acute 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of PD. AAV-hCDNF resulted in the expression of hCDNF in the striatum (STR) and substantia nigra (SN), and no toxic effects on the nigrostriatal pathway were observed. Intrastriatal injection of AAV-hCDNF reduced motor impairment and partially alleviated gait dysfunction in the acute MPTP mouse model. In addition, gene therapy with AAV-hCDNF had significant neuroprotective effects on the nigrostriatal pathway and decreased the levels of interleukin 1beta (IL-1ß) and complement 3 (C3) in glial cells in the acute MPTP mouse model. Moreover, AAV-hCDNF reduced C/EBP homologous protein (CHOP) and glucose regulatory protein 78 (GRP78) expression in astroglia. These results suggest that the neuroprotective effects of CDNF may be mediated at least in part through the regulation of neuroinflammation and the UPR pathway in a mouse MPTP model of PD in vivo.

PEDF-34 attenuates neurological deficit and suppresses astrocyte-dependent neuroinflammation by modulating astrocyte polarization via 67LR/JNK/STAT1 signaling pathway after subarachnoid hemorrhage in rats.

BACKGROUND: Reactive astrocytes participate in various pathophysiology after subarachnoid hemorrhage (SAH), including neuroinflammation, glymphatic-lymphatic system dysfunction, brain edema, BBB disruption, and cell death. Astrocytes transform into two new reactive phenotypes with changed morphology, altered gene expression, and secretion profiles, termed detrimental A1 and beneficial A2. This study investigates the effect of 67LR activation by PEDF-34, a PEDF peptide, on neuroinflammation and astrocyte polarization after the experimental SAH. METHODS: A total of 318 male adult Sprague-Dawley rats were used in experiments in vivo, of which 272 rats were subjected to the endovascular perforation model of SAH and 46 rats underwent sham surgery. 67LR agonist (PEDF-34) was administrated intranasally 1 h after SAH. 67LR-specific inhibitor (NSC-47924) and STAT1 transcriptional activator (2-NP) were injected intracerebroventricularly 48 h before SAH. Short- and long-term neurological tests, brain water content, immunostaining, Nissl staining, western blot, and ELISA assay were performed. In experiments in vitro, primary astrocyte culture with hemoglobin (Hb) stimulation was used to mimic SAH. The expression of the PEDF-34/67LR signaling pathway and neuro-inflammatory cytokines were assessed using Western blot, ELISA, and immunohistochemistry assays both in vivo and in vitro. RESULTS: Endogenous PEDF and 67LR expressions were significantly reduced at 6 h after SAH. 67LR was expressed in astrocytes and neurons. Intranasal administration of PEDF-34 significantly reduced brain water content, pro-inflammatory cytokines, and short-term and long-term neurological deficits after SAH. The ratio of p-JNK/JNK and p-STAT1/STAT1 and the expression of CFB and C3 (A1 astrocytes marker), significantly decreased after PEDF-34 treatment, along with fewer expression of TNF-α and IL-1ß at 24 h after SAH. However, 2-NP (STAT1 transcriptional activator) and NSC-47924 (67LR inhibitor) reversed the protective effects of PEDF-34 in vivo and in vitro by promoting A1 astrocyte polarization with increased inflammatory cytokines. CONCLUSION: PEDF-34 activated 67LR, attenuating neuroinflammation and inhibiting astrocyte A1 polarization partly via the JNK/STAT1 pathway, suggesting that PEDF-34 might be a potential treatment for SAH patients.

Biomarkers of Parkinson's disease in perspective of early diagnosis and translation of neurotrophic therapies.

Parkinson's disease (PD) is a common neurodegenerative disorder characterized by progressive loss of dopamine neurons and aberrant deposits of alpha-synuclein (α-syn) in the brain. The symptomatic treatment is started after the onset of motor manifestations in a late stage of the disease. Preclinical studies with neurotrophic factors (NTFs) show promising results of disease-modifying neuroprotective or even neurorestorative effects. Four NTFs have entered phase I-II clinical trials with inconclusive outcomes. This is not surprising because the preclinical evidence is from acute early-stage disease models, but the clinical trials included advanced PD patients. To conclude the value of NTF therapies, clinical studies should be performed in early-stage patients with prodromal symptoms, that is, before motor manifestations. In this review, we summarize currently available diagnostic and prognostic biomarkers that could help identify at-risk patients benefiting from NTF therapies. Focus is on biochemical and imaging biomarkers, but also other modalities are discussed. Neuroimaging is the most important diagnostic tool today, but α-syn imaging is not yet viable. Modern techniques allow measuring various forms of α-syn in cerebrospinal fluid, blood, saliva, and skin. Digital biomarkers and artificial intelligence offer new means for early diagnosis and longitudinal follow-up of degenerative brain diseases.

Treatment with walnut peptide ameliorates memory impairment in zebrafish and rats: promoting the expression of neurotrophic factors and suppressing oxidative stress.

Walnut peptide, a low molecular weight peptide separated from walnuts by enzymatic hydrolysis, is considered as a potential nutraceutical with a variety of biological activities. In this study, we characterized the walnut peptide prepared by alkaline protease hydrolysis and evaluated its neuroprotective effect in zebrafish and rat models of memory disorders. Series of concentrations of the walnut peptide were orally administered to zebrafish and rats to examine its impact on the behavior and biochemical indicators. The results showed that the oral administration of walnut peptide significantly ameliorated the behavioral performance in zebrafish exposed to bisphenol AF (1 µg mL-1) and rats exposed to alcohol (30% ethanol, 10 mL kg-1). Furthermore, the walnut peptide upregulated the expression of neurotrophic-related molecules in zebrafish, such as the brain-derived neurotrophic factor (BDNF) and the glial cell-derived neurotrophic factor (GDNF). In the rat brain, the walnut peptide increased the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), while dramatically reduced malondialdehyde (MDA) level. Together, these findings elucidated that the walnut peptide might partially offset the declarative memory deficits via regulation of neurotrophic-related molecule expression and promotion of the antioxidant defense ability. Therefore, walnut peptide holds the potential for development into functional foods as a nutritional supplement for the management of certain neurodegenerative disorders.

Spatiotemporal regulation of dental pulpal innervation in the rat.

The dental pulp is a highly innervated tissue transmitting pain-related sensations in the tooth. Consequently, understanding the intricacies of its innervation mechanism in odontogenesis is crucial for gaining insights into dental pain and developing dental pain-modulating agents. This study examined neuroregulatory molecules such as neurotrophic factors (nerve growth factor [NGF], brain-derived neurotrophic factor [BDNF], neurotrophin-4 [NTF-4], and neurturin [NRTN]) and neuroinhibitory factors (slit2, ephrin isoforms and netrin-1) in developing rat teeth with follicles. NGF, BDNF and NRTN transcriptions showed time-dependent upregulation, particularly during the root formation stage. In contrast, NTF-4 mRNA was highly expressed at the cap stage, but became downregulated over time. Slit2 and ephrin-B2 expression was distinct at the cap stage and then downregulated in a time-dependent manner. Ephrin-A5 and netrin-1 expression did not significantly change. Immunofluorescence analysis revealed a robust expression of both ephrin-B2 and slit2 in the outer and inner dental epithelia of the enamel organ, a non-neurogenic tissue, during the cap stage of 3rd molar germs. In contrast, BDNF was predominantly localized in dental papilla cells and odontoblasts during the root formation stage. These results suggest that neuroregulatory molecules, such as BDNF, slit2 and ephrin-B2, may be important in identifying therapeutic targets for modulating dental pulp pain.

Roles of pigment epithelium-derived factor in exercise-induced suppression of senescence and its impact on lung pathology in mice.

Senescent cells contribute to tissue aging and underlie the pathology of chronic diseases. The benefits of eliminating senescent cells have been demonstrated in several disease models, and the efficacy of senolytic drugs is currently being tested in humans. Exercise training has been shown to reduce cellular senescence in several tissues; however, the mechanisms responsible remain unclear. We found that myocyte-derived factors significantly extended the replicative lifespan of fibroblasts, suggesting that myokines mediate the anti-senescence effects of exercise. A number of proteins within myocyte-derived factors were identified by mass spectrometry. Among these, pigment epithelium-derived factor (PEDF) exerted inhibitory effects on cellular senescence. Eight weeks of voluntary running increased Pedf levels in skeletal muscles and suppressed senescence markers in the lungs. The administration of PEDF reduced senescence markers in multiple tissues and attenuated the decline in respiratory function in the pulmonary emphysema mouse model. We also showed that blood levels of PEDF inversely correlated with the severity of COPD in patients. Collectively, these results strongly suggest that PEDF contributes to the beneficial effects of exercise, potentially suppressing cellular senescence and its associated pathologies.

Stable inhibition of choroidal neovascularization by adeno-associated virus 2/8-vectored bispecific molecules.

Neovascular age-related macular degeneration (nAMD) causes severe visual impairment. Pigment epithelium-derived factor (PEDF), soluble CD59 (sCD59), and soluble fms-like tyrosine kinase-1 (sFLT-1) are potential therapeutic agents for nAMD, which target angiogenesis and the complement system. Using the AAV2/8 vector, two bi-target gene therapy agents, AAV2/8-PEDF-P2A-sCD59 and AAV2/8-sFLT-1-P2A-sCD59, were generated, and their therapeutic efficacy was investigated in laser-induced choroidal neovascularization (CNV) and Vldlr-/- mouse models. After a single injection, AAV2/8-mediated gene expression was maintained at high levels in the retina for two months. Both AAV2/8-PEDF-P2A-sCD59 and AAV2/8-sFLT-1-P2A-sCD59 significantly reduced CNV development for an extended period without side effects and provided efficacy similar to two injections of current anti-vascular endothelial growth factor monotherapy. Mechanistically, these agents suppressed the extracellular signal-regulated kinase and nuclear factor-κB pathways, resulting in anti-angiogenic activity. This study demonstrated the safety and long-lasting effects of AAV2/8-PEDF-P2A-sCD59 and AAV2/8-sFLT-1-P2A-sCD59 in CNV treatment, providing a promising therapeutic strategy for nAMD.

PEDF and 34-mer peptide inhibit cardiac microvascular endothelial cell ferroptosis via Nrf2/HO-1 signalling in myocardial ischemia-reperfusion injury.

Myocardial ischemia-reperfusion injury (MIRI) represents a critical pathology in acute myocardial infarction (AMI), which is characterized by high mortality and morbidity. Cardiac microvascular dysfunction contributes to MIRI, potentially culminating in heart failure (HF). Pigment epithelium-derived factor (PEDF), which belongs to the non-inhibitory serpin family, exhibits several physiological effects, including anti-angiogenesis, anti-inflammatory and antioxidant properties. Our study aims to explore the impact of PEDF and its functional peptide 34-mer on both cardiac microvascular perfusion in MIRI rats and human cardiac microvascular endothelial cells (HCMECs) injury under hypoxia reoxygenation (HR). It has been shown that MIRI is accompanied by ferroptosis in HCMECs. Furthermore, we investigated the effect of PEDF and its 34-mer, particularly regarding the Nrf2/HO-1 signalling pathway. Our results demonstrated that PEDF 34-mer significantly ameliorated cardiac microvascular dysfunction following MIRI. Additionally, they exhibited a notable suppression of ferroptosis in HCMECs, and these effects were mediated through activation of Nrf2/HO-1 signalling. These findings highlight the therapeutic potential of PEDF and 34-mer in alleviating microvascular dysfunction and MIRI. By enhancing cardiac microvascular perfusion and mitigating endothelial ferroptosis, PEDF and its derivative peptide represent promising candidates for the treatment of AMI.

Programmed cell death: NINJ1 and mechanisms of plasma membrane rupture.

Lytic cell death culminates in cell swelling and plasma membrane rupture (PMR). The cellular contents released, including proteins, metabolites, and nucleic acids, can act as danger signals and induce inflammation. During regulated cell death (RCD), lysis is actively initiated and can be preceded by an initial loss of membrane integrity caused by pore-forming proteins, allowing small molecules and cytokines to exit the cell. A recent seminal discovery showed that ninjurin1 (NINJ1) is the common executioner of PMR downstream of RCD, resulting in the release of large proinflammatory molecules and representing a novel target of cell death-associated lysis. We summarize recent developments in understanding membrane integrity and rupture of the plasma membrane with a focus on NINJ1.

Pigment epithelium-derived factor expression and role in follicular development.

RESEARCH QUESTION: What is the involvement of pigment epithelium-derived factor (PEDF), expressed in granulosa cells, in folliculogenesis? DESIGN: mRNA expression of PEDF and other key factors [Cyp19, anti-Müllerian hormone receptor (AMHR) and vascular endothelial growth factor (VEGF)] in mice follicles was examined in order to typify the expression of PEDF in growing follicles and in human primary granulosa cells (hpGC), and to follow the interplay between PEDF and the other main players in folliculogenesis: FSH and AMH. RESULTS: mRNA expression of PEDF increased through folliculogenesis, although the pattern differed from that of the other examined genes, affecting the follicular angiogenic and oxidative balance. In hpGC, prolonged exposure to FSH stimulated the up-regulation of PEDF mRNA. Furthermore, a negative correlation between AMH and PEDF was observed: AMH stimulation reduced the expression of PEDF mRNA and PEDF stimulation reduced the expression of AMHR mRNA. CONCLUSIONS: Folliculogenesis, an intricate process that requires close dialogue between the oocyte and its supporting granulosa cells, is mediated by various endocrine and paracrine factors. The current findings suggest that PEDF, expressed in granulosa cells, is a pro-folliculogenesis player that interacts with FSH and AMH in the process of follicular growth. However, the mechanism of this process is yet to be determined.

Combined Ionizing Radiation Exposure by Gamma Rays and Carbon-12 Nuclei Increases Neurotrophic Factor Content and Prevents Age-Associated Decreases in the Volume of the Sensorimotor Cortex in Rats.

In orbital and ground-based experiments, it has been demonstrated that ionizing radiation (IR) can stimulate the locomotor and exploratory activity of rodents, but the underlying mechanism of this phenomenon remains undisclosed. Here, we studied the effect of combined IR (0.4 Gy γ-rays and 0.14 Gy carbon-12 nuclei) on the locomotor and exploratory activity of rats, and assessed the sensorimotor cortex volume by magnetic resonance imaging-based morphometry at 1 week and 7 months post-irradiation. The sensorimotor cortex tissues were processed to determine whether the behavioral and morphologic effects were associated with changes in neurotrophin content. The irradiated rats were characterized by increased locomotor and exploratory activity, as well as novelty-seeking behavior, at 3 days post-irradiation. At the same time, only unirradiated rats experienced a significant decrease in the sensorimotor cortex volume at 7 months. While there were no significant differences at 1 week, at 7 months, the irradiated rats were characterized by higher neurotrophin-3 and neurotrophin-4 content in the sensorimotor cortex. Thus, IR prevents the age-associated decrease in the sensorimotor cortex volume, which is associated with neurotrophic and neurogenic changes. Meanwhile, IR-induced increases in locomotor activity may be the cause of the observed changes.