IGF-1 Inhibits Apoptosis of Porcine Primary Granulosa Cell by Targeting Degradation of BimEL

The impact of Apis dorsata forest honey administration on follicle-stimulating hormone and luteinizing hormone levels in rats (Rattus norvegicus) forced swim test as a chronic physical animal model

Background

Chronic physical stress has many effects on the nervous system and can cause structural changes in different parts of the brain and hemomodulatory, including hormonal. Current pharmacotherapeutic treatments have limited efficacy and are associated with many deleterious side effects.

Aim

The aim of this research is to determine how Apis dorsata forest honey administration affects follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels in rats who are subjected to forced swim tests as a model of chronic physical stress placed in a container filled with water from which it cannot escape.

Methods

This was an experimental laboratory study with 32 rats divided into four treatment groups: control (C), Treatment 1 (T1) with a forced swim test + honey (2 g/rat/day), Treatment 2 (T2) with a forced swim test + honey (4 g/rat/day), and Treatment 3 (T3) with a forced swim test + honey (6 g/rat/day). All treatments were administered for 14 days. Then, blood was taken for FSH and LH serum tests, and a one-way ANOVA and Duncan test were used to statistically test the data analysis.

Results

The results of this study indicate that the administration of forest honey had no significant effect (p > 0.05) on the FSH parameter, but there was a significant decrease in LH levels in the T2 and T3 groups (p < 0.05).

Conclusion

It can be concluded that giving forest honey to rats who were subjected to a 14-day forced swim test had no effect on FSH and LH levels. In rats given a forced swim test as a model of chronic stress, administration at doses of 4 and 6 g/rat/day reduced LH serum levels. Thus, giving forest honey could maintain reproductive health in rat that experience chronic stress.

IGF‑1 inhibits palmitic acid‑induced mitochondrial apoptosis in macrophages

Insulin growth factor‑1 (IGF‑1) is an endocrine regulator that plays an important role in normal growth and development. IGF‑1 mediated effects may result in protecting macrophages from immunometabolic response. However, it is unclear whether IGF‑1 has a protective effect on fatty acid‑induced macrophages damage. In the present study, THP‑1 cells were differentiated into macrophages and stimulated with palmitic acid (PA) in the absence or presence of IGF‑1. Macrophages apoptosis was measured by Cell Counting Kit‑8 assay, flow cytometry, Hoechst 33342 staining and western blotting. The mitochondrial damage was evaluated using JC‑1 staining and mitochondrial reactive oxygen species detection. The activation of mitophagy was assessed using immunofluorescence and western blotting. As a result, IGF‑1 significantly restored the survival rate in macrophages, while the apoptosis was inhibited through mitochondrial pathway. In addition, IGF‑1 protected the mitochondrial damage induced by PA. Furthermore, PA induced mitophagy via phosphatase and tensin homolog‑induced putative kinase protein 1/Parkin, which was reversed by IGF‑1. Taken together, the present study demonstrated the protective effect of IGF‑1 on PA‑induced mitochondrial apoptosis in macrophages, which might provide a potential therapeutic strategy for treatment of lipotoxicity.

Effects of insulin-like growth factor-1 on the proliferation and apoptosis of stallion testicular cells under normal and heat stress culture conditions

This study investigated the effect of heat stress on stallion testicular cells (TCs) and the effect of insulin-like growth factor (IGF)-1 on TC viability, proliferation, and apoptosis, including different stages of germ cells. TCs were divided into control or treatment groups with 0.01, 0.1, 1, 10, and 100 ng/mL of recombinant human IGF-1 (rhIGF-1) for 24 h at 34 °C and 37 °C. The population and viability were measured before and after treatment. The effects of rhIGF-1 on TC viability, proliferation, and apoptosis were determined using RT-qPCR. Proliferating cell nuclear antigen (PCNA) and marker of proliferation Ki-67 (MKI-67) were used as proliferation markers. Myeloid leukemia-1 (MCL-1) was used as an antiapoptotic marker. BCL2 antagonist/killer-1 (BAK-1) was used as a proapoptotic marker. The relative abundance of mRNA transcript of undifferentiated cell transcription factor 1 (UTF-1), protein gene product 9.5 (PGP9.5), and deleted in azoospermia-like (DAZL), was measured for spermatogenesis progression. TCs treated with 1 ng/mL rhIGF-1 at 34 °C exhibited the highest viability. Significant upregulation of the relative abundance of mRNA transcript of PCNA, MKI-67, and MCL-1 was observed in treated TCs compared with untreated TCs; however, BAK-1 was significantly downregulated in treated TCs. Germ cells treated with 1 ng/mL rhIGF-1 exhibited the highest relative abundance of mRNA transcript of UTF-1 and DAZL, whereas TCs exposed to 0.1 ng/mL showed the highest PGP9.5 level. These data confirm that heat stress in stallions decreases TC viability. These findings may help identify a basal IGF-1 level for TC proliferation and apoptosis during heat stress-induced testicular degeneration in stallions.

Current Advances in Cellular Approaches for Pathophysiology and Treatment of Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a prevalent gynecological and endocrine disorder that results in irregular menstruation, incomplete follicular development, disrupted ovulation, and reduced fertility rates among affected women of reproductive age. While these symptoms can be managed through appropriate medication and lifestyle interventions, both etiology and treatment options remain limited. Here we provide a comprehensive overview of the latest advancements in cellular approaches utilized for investigating the pathophysiology of PCOS through in vitro cell models, to avoid the confounding systemic effects such as in vitro fertilization (IVF) therapy. The primary objective is to enhance the understanding of abnormalities in PCOS-associated folliculogenesis, particularly focusing on the aberrant roles of granulosa cells and other relevant cell types. Furthermore, this article encompasses analyses of the mechanisms and signaling pathways, microRNA expression and target genes altered in PCOS, and explores the pharmacological approaches considered as potential treatments. By summarizing the aforementioned key findings, this article not only allows us to appreciate the value of using in vitro cell models, but also provides guidance for selecting suitable research models to facilitate the identification of potential treatments and understand the pathophysiology of PCOS at the cellular level.

Characterization of polymorphisms in the follicle-stimulating hormone receptor and insulin-like growth factor-1 genes and their association with fertility traits in Jawa-Brebes cows

Background and Aim

The availability of fertility markers is crucial for maintaining, protecting, and improving the genetics of Jawa-Brebes (Jabres) cows. Follicle-stimulating hormone receptor (FSHR) and insulin-like growth factor-1 (IGF-1) play critical roles in female reproductive physiology. The single-nucleotide polymorphisms (SNPs) FSHR G-278A and IGF-1 C-512T correlate with cows' fertility traits. This study aimed to identify these SNPs and their potential associations with fertility parameters in Jabres cows.

Materials and Methods

Samples were collected from 45 heads of multiparous Jabres cows aged 3-10 years with body condition scores of 2.5-5.0 on a 5-point scale in Brebes Regency, Java, Indonesia. These cows were assigned to fertile (n = 16) and infertile groups (n = 29). Polymerase chain reaction (PCR) was carried out for DNA amplification of FSHR G-278A and IGF-1 C-512T fragments. Restriction fragment length polymorphism-PCR with the restriction enzymes FaqI for the product of FSHR G-278A and SnaBI for the product of IGF-1 C-512T was used to identify SNPs.

Results

The FaqI enzyme cut the 211 bp DNA fragment of FSHR G-278A in all samples into two bands of 128 bp and 83 bp (GG genotype). Meanwhile, the genotyping of amplicon products of IGF-1 C-512T generated a single 249 bp fragment (CC genotype) in both groups.

Conclusion

The results showed that the FSHR G-278A/FaqI and IGF-1 C-512T/SnaBI loci were monomorphic in Jabres cows. Thus, neither FSHR G-278A/FaqI nor IGF-1 C-512T/SnaBI is a possible genetic marker for fertility in Jabres cows.

Arsenic trioxide promotes ERK1/2-mediated phosphorylation and degradation of BIMEL to attenuate apoptosis in BEAS-2B cells

Inorganic arsenic is highly toxic, widely distributed in the human environment and may result in multisystem diseases and several types of cancers. The BCL-2-interacting mediator of cell death protein (BIM) is a key modulator of the intrinsic apoptosis pathway. Interestingly, in the present study, we found that arsenic trioxide (As₂O₃) decreased BIM_EL levels in human bronchial epithelial cell line BEAS-2B and increased BIM_EL levels in human lung carcinoma cell line A549 and mouse Sertoli cell line TM4. Mechanismly, the 26S proteasome inhibitors MG132 and bortezomib could effectively inhibit BIM_EL degradation induced by As₂O₃ in BEAS-2B cells. As₂O₃ activated extracellular signal-regulated kinase (ERK) 1/2, c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK) signaling pathways, but only the ERK1/2 MAPK inhibitor PD98059 blocked BIM_EL degradation induced by As₂O₃. Furthermore, As₂O₃ induced-phosphorylation of BIM_EL at multiple sites was inhibited by ERK1/2 MAPK inhibitor PD98059. Inhibition of As₂O₃-induced ERK1/2 MAPK phosphorylation increased the levels of BIM_EL and cleaved-caspase-3 proteins and decreased BEAS-2B cell viability. As₂O₃ also markedly mitigated tunicamycin-induced apoptosis of BEAS-2B cells by increasing ERK1/2 phosphorylation and BIM_EL degradation. Our results suggest that As₂O₃-induced activation of the ERK1/2 MAPK pathway increases phosphorylation of BIM_EL and promotes BIM_EL degradation, thereby alleviating the role of apoptosis in As₂O₃-induced cell death. This study provides new insights into how to maintain the survival of BEAS-2B cells before malignant transformation induced by high doses of As₂O₃.

IGF-Binding Proteins and Their Proteolysis as a Mechanism of Regulated IGF Release in the Nervous Tissue

Insulin-like growth factors 1 and 2 (IGF-1 and IGF-2) play a key role in the maintenance of the nervous tissue viability. IGF-1 and IGF-2 exhibit the neuroprotective effects by stimulating migration and proliferation of nervous cells, activating cellular metabolism, inducing regeneration of damaged cells, and regulating various stages of prenatal and postnatal development of the nervous system. The availability of IGFs for the cells is controlled via their interaction with the IGF-binding proteins (IGFBPs) that inhibit their activity. On the contrary, the cleavage of IGFBPs by specific proteases leads to the IGF release and activation of its cellular effects. The viability of neurons in the nervous tissue is controlled by a complex system of trophic factors secreted by auxiliary glial cells. The main source of IGF for the neurons are astrocytes. IGFs can accumulate as an extracellular free ligand near the neuronal membranes as a result of proteolytic degradation of IGFBPs by proteases secreted by astrocytes. This mechanism promotes interaction of IGFs with their genuine receptors and triggers intracellular signaling cascades. Therefore, the release of IGF by proteolytic cleavage of IGFBPs is an important mechanism of neuronal protection. This review summarizes the published data on the role of IGFs and IGFBPs as the key players in the neuroprotective regulation with a special focus on the specific proteolysis of IGFBPs as a mechanism for the regulation of IGF bioavailability and viability of neurons.

Kurarinone attenuates hydrogen peroxide-induced oxidative stress and apoptosis through activating the PI3K/Akt signaling by upregulating IGF1 expression in human ovarian granulosa cells

Dysregulated follicular development may lead to follicular atresia, and this is associated with oxidative stress in granulosa cells. Kurarinone is a natural compound possessing multiple activities, including antioxidative ability. However, the role of kurarinone in granulosa cell damage during follicular atresia remains unknown. Human ovarian granulosa KGN cells were treated with hydrogen peroxide (H₂ O₂ ) to induce cellular damage. Cytotoxicity was investigated by lactate dehydrogenase (LDH) release assay. Oxidative stress was evaluated by detection of reactive oxygen species (ROS) generation and oxidative biomarker levels. Cell apoptosis was evaluated by flow cytometry, a Cell Death Detection ELISA Kit, and a Caspase-3 Assay Kit. The downstream target and related signaling pathway were analyzed by western blotting. Kurarinone attenuated H₂ O₂ -induced LDH release in KGN cells. Kurarinone relieved H₂ O₂ -induced increase in ROS generation and malondialdehyde level as well as decrease in superoxide dismutase-1 activity and heme oxygenase 1 and NAD(P)H quinone dehydrogenase 1 mRNA levels. Kurarinone inhibited H₂ O₂ -induced apoptosis in KGN cells. Kurarinone targeted insulin-like growth factor 1 (IGF1) and upregulated IGF1 expression to activate the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) signaling. IGF1 silencing attenuated the suppressive effects of kurarinone on H₂ O₂ -induced oxidative stress and apoptosis in KGN cells. In conclusion, kurarinone attenuates H₂ O₂ -induced oxidative stress and apoptosis in KGN cells through activating the PI3K/Akt signaling by upregulating IGF1 expression, indicating the therapeutic potential of kurarinone in follicular atresia.

The Photoperiod Regulates Granulosa Cell Apoptosis through the FSH-Nodal/ALK7 Signaling Pathway in Phodopus sungorus

The photoperiod regulates the seasonal reproduction of mammals by affecting the follicle development, for which the granulosa cells provide nutrition. However, the underlying mechanism remains unclear. Here, Djungarian hamsters (Phodopus sungorus) were raised under different photoperiods to study the ovarian status and explore the potential mechanism of the follicle development mediated by the FSH-Nodal/ALK7 signaling pathway. Compared with the moderate daylight (MD) group, the short daylight (SD) group exhibited a significant decrease in the ovarian weight and increase in the atretic follicle number and granulosa cell apoptosis, whereas the long daylight (LD) group showed an increase in the ovarian weight, the growing follicle number, and the antral follicle number, but a decrease in the granulosa cell apoptosis. Based on these findings, the key genes of the Nodal/ALK7 signaling pathway controlling the granulosa cell apoptosis were studied using the quantitative real-time polymerase chain reaction and western blotting. In the SD group, the follicle-stimulating hormone (FSH) concentration significantly decreased and the Nodal/ALK7/Smad signaling pathways were activated, while the phosphatidylinositol 3-kinase (PIK3)/Akt signaling pathway was inhibited. The BAX expression was significantly increased, while the Bcl-xL expression was significantly decreased, leading to an increase in the caspase-3 activity, the granulosa cell apoptosis, and ovarian degeneration. However, in the LD group, the FSH concentration significantly increased, the Nodal/ALK7/Smad signaling pathway was inhibited, and the PIK3/Akt signaling pathway was activated. Taken together, our results indicate that the photoperiod can regulate the apoptosis of the granulosa cells by regulating the concentration of FSH, activating or inhibiting the Nodal/ALK7 signaling pathway, thereby affecting the ovarian function. Our research provides an important theoretical basis for understanding the photoperiod-regulated mechanisms of the mammalian seasonal reproduction.

Leptin Promotes Primordial Follicle Activation by Regulating Ovarian Insulin-like Growth Factor System in Chicken

Leptin and insulin-like growth factor 1 (IGF-1) regulate follicle development and reproduction in vertebrates. This study investigated the role played by leptin and IGF-1 in primordial follicle activation in the ovary of 7-day-old chicks. Different doses of leptin were intraperitoneally administrated to female layer chicks, and further analyses were performed. While leptin administration did not affect hepatic leptin receptor (LEPR), growth hormone receptor (GHR), or IGF-1, the lower dose of leptin significantly increased the messenger RNA (mRNA) expression of IGF-1, IGF-1 receptor, and IGF-binding protein (IGFBP)-2 and attenuated anti-Müllerian hormone (AMH) gene expression in the ovary. Furthermore, the ovaries of the same age chicks were challenged with leptin and/or IGF-1 in vitro. Leptin at a lower dose increased the mRNA expression of IGF-1, LEPR, and leptin; 100 ng/mL leptin and 10 ng/mL IGF-1 alone or combined with leptin reduced IGFBP-2 mRNA expression. AMH gene expression was also reduced by all doses except 10 ng/mL leptin. Histological studies showed that a lower dose of leptin injection induced the primordial follicle growth in the ovary in vivo, and the number of primordial follicles was higher in all leptin treatments over control in vitro. Moreover, the luciferase assay revealed that leptin enhanced IGF-1 promoter activity in LEPR-expressing CHO-K1 cells. Collectively, these results indicate that leptin directly affects the IGF-1/IGFBP system and promotes primordial follicular growth in the ovary of early posthatch chicks. In addition, the follicular development by leptin-induced IGF-1 is, at least in part, caused by the suppression of AMH in the ovary.

IGF-1 as a Potential Therapy for Spinocerebellar Ataxia Type 3

Although the effects of growth hormone (GH) therapy on spinocerebellar ataxia type 3 (SCA3) have been examined in transgenic SCA3 mice, it still poses a nonnegligible risk of cancer when used for a long term. This study investigated the efficacy of IGF-1, a downstream mediator of GH, in vivo for SCA3 treatment. IGF-1 (50 mg/kg) or saline, once a week, was intraperitoneally injected to SCA3 84Q transgenic mice harboring a human ATXN3 gene with a pathogenic expanded 84 cytosine–adenine–guanine (CAG) repeat motif at 9 months of age. Compared with the control mice harboring a 15 CAG repeat motif, the SCA3 84Q mice treated with IGF-1 for 9 months exhibited the improvement only in locomotor function and minimized degeneration of the cerebellar cortex as indicated by the survival of more Purkinje cells with a more favorable mitochondrial function along with a decrease in oxidative stress caused by DNA damage. These findings could be attributable to the inhibition of mitochondrial fission, resulting in mitochondrial fusion, and decreased immunofluorescence staining in aggresome formation and ataxin-3 mutant protein levels, possibly through the enhancement of autophagy. The findings of this study show the therapeutic potential effect of IGF-1 injection for SCA3 to prevent the exacerbation of disease progress.

SMAD4-induced knockdown of the antisense long noncoding RNA BRE-AS contributes to granulosa cell apoptosis

Antisense long noncoding RNAs (AS-lncRNAs), a sub-class of lncRNAs, are transcribed in the opposite direction from their overlapping protein-coding genes and are implicated in various physiological and pathological processes. However, their role in female reproduction remains largely unknown. Here, we report that BRE-AS, an AS-lncRNA transcript from intron 10 of the protein-coding gene BRE, is involved in granulosa cell (GC) apoptosis. Based on our previous RNA sequencing data, we identified 28 AS-lncRNAs as important in the initiation of porcine follicular atresia, with BRE-AS showing the most significant upregulation in early atretic follicles. In this study, gain- and loss-of-function assays demonstrated that BRE-AS induces early apoptosis in GCs. Mechanistically, BRE-AS acts in cis to suppress the expression of BRE, an anti-apoptotic factor, via direct interaction with the pre-mRNA transcript of the latter, inducing increased GC apoptosis. Notably, we also found that BRE-AS was upregulated in SMAD4-silenced GCs. SMAD4 was identified as a transcriptional repressor of BRE-AS because it inhibits BRE-AS expression and BRE-AS-mediated GC apoptosis. In conclusion, we not only identified a novel AS-lncRNA related to the early apoptosis of GCs and initiation of follicular atresia but also described a novel regulatory pathway, SMAD4/BRE-AS/BRE, coordinating GC function and female fertility.

TGF-β1 controls porcine granulosa cell states: A miRNA-mRNA network view

TGF-β1, an important multi-functional cytokine of the TGF-β signaling pathway, has been reported to be crucial for ovarian granulosa cell (GC) states and female fertility. However, the molecular mechanism underlying TGF-β1 regulation of GC states remains largely unknown. Here, we provide a comprehensive transcriptomic view on TGF-β1 regulation of cell states in porcine GCs. We first confirmed that TGF-β1 can control GC states (apoptosis and proliferation) in pig ovary. RNA-seq showed that 909 differentially expressed genes (DEGs), including 890 DEmRNAs and 19 DEmiRNAs, were identified in TGF-β1-treated porcine GCs. Functional annotation showed that these DEGs were mainly involved in regulating cell states. In addition, multiple hub genes were identified by constructing the protein-protein interaction network, DEmiRNA-DEmRNAs regulatory network, and gene-pathway-function co-expression networks, which were further found to be enriched in FoxO, TGF-β, Wnt, PIK3-Akt, p53 and Ras signaling pathways that play important roles in regulating cell states, cell cycle, proliferation, stress-responses and inflammation. The current research deeply reveals the effects of TGF-β1 on porcine GCs, and also identifies potential therapeutic RNA molecules for inhibiting and rescuing female infertility.

Degradation of Mutant Protein Aggregates within the Endoplasmic Reticulum of Vasopressin Neurons

Misfolded or unfolded proteins in the ER are said to be degraded only after translocation or isolation from the ER. Here, we describe a mechanism by which mutant proteins are degraded within the ER. Aggregates of mutant arginine vasopressin (AVP) precursor were confined to ER-associated compartments (ERACs) connected to the ER in AVP neurons of a mouse model of familial neurohypophysial diabetes insipidus. The ERACs were enclosed by membranes, an ER chaperone and marker protein of phagophores and autophagosomes were expressed around the aggregates, and lysosomes fused with the ERACs. Moreover, lysosome-related molecules were present within the ERACs, and aggregate degradation within the ERACs was dependent on autophagic-lysosomal activity. Thus, we demonstrate that protein aggregates can be degraded by autophagic-lysosomal machinery within specialized compartments of the ER.

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Mutant AVP precursors are confined to ERACs connected to the ER of FNDI AVP neurons

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Lysosomes fuse with ERACs surrounded by phagophore-like membranes

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Lysosome-related molecules are localized within ERACs

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Rapamycin reduces and chloroquine increases protein aggregate accumulation in ERACs

Dynamics and Regulations of BimEL Ser65 and Thr112 Phosphorylation in Porcine Granulosa Cells during Follicular Atresia

BimEL protein is involved in follicular atresia by regulating granulosa cell apoptosis, but the dynamic changes of BimEL phosphorylation during follicular atresia are poorly understood. The aim of this study was to explore the changes of key BimEL phosphorylation sites and their upstream regulatory pathways. First, the levels of BimEL-Ser65 and BimEL-Thr112 phosphorylation (p-BimEL-S65, p-BimEL-T112) in granulosa cells (GC) from healthy (H), slightly-atretic (SA), and atretic (A) follicles and in cultured GC after different treatments were detected by Western blotting. Next, the effects of the corresponding site mutations of BIM on apoptosis of GC were investigated. Finally, the pathways of two phosphorylation sites were investigated by kinase inhibitors. The results revealed that p-BimEL-S65 levels were higher in GC from H than SA and A, whereas p-BimEL-T112 was reversed. The prosurvival factors like FSH and IGF-1 upregulated the level of p-BimEL-S65, while the proapoptotic factor, heat stress, increased the level of p-BimEL-T112 in cultured GC. Compared with the overexpression of wild BimEL, the apoptotic rate of the GC overexpressed BimEL-S65A (replace Ser65 with Ala) mutant was significantly higher, but the apoptotic rate of the cells overexpressing BimEL-T112A did not differ. In addition, inhibition of the ERK1/2 or JNK pathway by specific inhibitors reduced the levels of p-BimEL-S65 and p-BimEL-T112. In conclusion, the levels of p-BimEL-S65 and p-BimEL-T112 were reversed during follicular atresia. Prosurvival factors promote p-BimEL-S65 levels via ERK1/2 to inhibit GC apoptosis, whereas proapoptotic factor upregulates the level of p-BimEL-T112 via JNK to induce GC apoptosis.