Insulin-like growth factor-1 attenuates oxidative stress-induced hepatocyte premature senescence in liver fibrogenesis via regulating nuclear p53-progerin interaction

Pharmacological blockade of infection chronification modulates oxy-inflammation and prevents the activation of stress-induced premature senescence markers in schistosomiasis

Chronic inflammation, oxidative stress, and DNA damage are observed in schistosomiasis and premature aging. However, the potential of these events to trigger stress-induced premature senescence (SIPS) throughout schistosomiasis progression remains overlooked, especially in response to the first-line pharmacological treatment. Thus, we investigated the relationship between oxidative stress and SIPS sentinel markers in untreated Schistosoma mansoni-infected mice and those receiving praziquantel (Pz)-based reference treatment. Swiss mice were randomized into 5 groups: uninfected (followed by 60- and 180-days post-infection), acutely (60 days) and chronically (180 days) infected untreated, and infected treated with Pz followed until 180 days. Our results indicated that infection chronification was accompanied by the worsening of hepatic granulomatous inflammation, increased number of granulomas, IL-4, TGF-β, reactive oxygen species (ROS) levels, fibrosis, hepatocytes DNA damage, upregulation in SA-β-gal activity, p16 and p21 gene expression, and hepatocytes proliferation down-regulation in the absence of telomeric shortening. These abnormalities were blocked by Pz treatment, which prevented infection chronification and the decline in hepatocytes proliferative potential, stimulating granulomatous inflammation resolution. Taken together, our findings provide the evidence that progressive fibrosis, sustained production of high ROS levels, marked DNA damage and decline in p16 and p21 expression are associated with hepatocytes replication attenuation in the chronic phase of S. mansoni infection. Thus, pharmacological blockade of infection and granulomatous inflammation is essential to prevent these premature senescence markers associated with hepatocytes replicative disorders, stimulating liver regeneration in schistosomiasis mansoni.

Deacetylation of HnRNP U mediated by sirtuin1 ameliorates aged rat with liver fibrosis via inhibiting p53-related senescence and NLRP3-related inflammation

Senescence represents a major risk factor promoting liver fibrosis progression. Sirtuin 1 (SIRT1), an essential regulator of cellular senescence, may be involved in developing liver fibrosis. However, the role and mechanism of SIRT1 in liver fibrosis development were largely unknown. We constructed the liver fibrosis in aged rats induced by carbon tetrachloride (CCl4) and then transfected with GFP-SIRT1 adenoviral vectors. After that, we performed acetylomic analysis of liver tissue in aged rats to identify potential substrates of SIRT1. Furthermore, replicative senescent rat hepatocytes were pretreated with siRNA HnRNP U, SIRT1 adenoviral vectors, resveratrol, and siRNA SIRT1, following stimulation with H2O2. We found that the protein levels of SIRT1 and HnRNP U were down-regulation in aged rat liver fibrotic tissues, with an accumulation of NLRP3 inflammasome and activation of the p53/p21 pathway in liver tissue, as well as an increased level of plasma IL-1β secretion. In comparison, these effects were reversed by overexpressing SIRT1 with adenoviral vectors. Acetylation of HnRNP U and its sites at K28 and K787 might be potential targets for SIRT1-mediated liver fibrosis in aged rats. Silencing HnRNP U reduced H2O2-induced up-regulation expression of p53, p21, and NLRP3 inflammasome at protein levels. Additionally, H2O2 induced high acetylation of HnRNP U in senescent hepatocytes, whereas overexpressing SIRT1 with adenoviral vectors and resveratrol deacetylate HnRNP U to inhibit NLRP3 inflammasome and the p53/p21 pathway. Besides, the silence of SIRT1 aggravated H2O2-induced p53-related senescence and NLRP3-related inflammation in senescent hepatocytes. Our findings suggested that deacetylation of HnRNPU mediated by SIRT1 attenuated liver fibrosis in the elderly by inhibiting p53/p21 pathway and NLRP3-related inflammation.

Proteomic and metabolomic analysis of GH deficiency-induced NAFLD in hypopituitarism: insights into oxidative stress

Objective

Individuals with hypopituitarism (HPs) have an increased risk of developing non-alcoholic fatty liver disease (NAFLD)/non-alcoholic steatohepatitis (NASH) due to growth hormone deficiency (GHD). We aimed to investigate the possible mechanisms underlying the relationship between GHD and NAFLD using proteomic and metabolomic insights.

Methods

Serum metabolic alternations were assessed in male HPs using untargeted metabolomics. A rat model of HP was established through hypophysectomy, followed by recombinant human growth hormone (rhGH) intervention. The mechanisms underlying GHD-mediated NAFLD were elucidated through the application of label-free proteomics and phosphorylation proteomics.

Results

Metabolomic analysis revealed that biomarkers of mitochondrial dysfunction and oxidative stress, such as alanine, lactate, and creatine, were significantly elevated in HPs compared to age-matched controls. In rats, hypophysectomy led to marked hepatic steatosis, lipid peroxidation, and reduced glutathione (GSH), which were subsequently modulated by rhGH replacement. Proteomic analysis identified cytochrome P450s, mitochondrial translation elongation, and PPARA activating genes as the major distinguishing pathways in hypophysectomized rats. The processes of fatty acid transport, synthesis, oxidation, and NADP metabolism were tightly described. An enhanced regulation of peroxisome β-oxidation and ω-oxidation, together with a decreased NADPH regeneration, may exacerbate oxidative stress. Phosphoproteome data showed downregulation of JAK2-STAT5B and upregulation of mTOR signaling pathway.

Conclusions

This study identified proteo-metabolomic signatures associated with the development of NAFLD in pituitary GHD. Evidence was found of oxidative stress imbalance resulting from abnormal fatty acid oxidation and NADPH regeneration, highlighting the role of GH deficiency in the development of NAFLD.

Targeting tumor suppressor p53 for organ fibrosis therapy

Fibrosis is a reparative and progressive process characterized by abnormal extracellular matrix deposition, contributing to organ dysfunction in chronic diseases. The tumor suppressor p53 (p53), known for its regulatory roles in cell proliferation, apoptosis, aging, and metabolism across diverse tissues, appears to play a pivotal role in aggravating biological processes such as epithelial-mesenchymal transition (EMT), cell apoptosis, and cell senescence. These processes are closely intertwined with the pathogenesis of fibrotic disease. In this review, we briefly introduce the background and specific mechanism of p53, investigate the pathogenesis of fibrosis, and further discuss p53's relationship and role in fibrosis affecting the kidney, liver, lung, and heart. In summary, targeting p53 represents a promising and innovative therapeutic approach for the prevention and treatment of organ fibrosis.

U-Shaped relationship of insulin-like growth factor I and incidence of nonalcoholic fatty liver in patients with pituitary neuroendocrine tumors: a cohort study

Context

Although the role of insulin-like growth factor I (IGF-1) in nonalcoholic fatty liver disease (NAFLD) has garnered attention in recent years, few studies have examined both reduced and elevated levels of IGF-1.

Objective

The aim of this study was to examine the potential relationship between IGF-1 levels and the risk of new-onset NAFLD in patients with pituitary neuroendocrine tumors (PitNET).

Methods

We employed multivariable Cox regression models and two-piecewise regression models to assess the association between IGF-1 and new-onset NAFLD. Hazard ratios (HRs) and their corresponding 95% confidence intervals (CIs) were calculated to quantify this association. Furthermore, a dose-response correlation between lgIGF-1 and the development of NAFLD was plotted. Additionally, we also performed subgroup analysis and a series sensitivity analysis.

Results

A total of 3,291 PitNET patients were enrolled in the present study, and the median duration of follow-up was 65 months. Patients with either reduced or elevated levels of IGF-1 at baseline were found to be at a higher risk of NAFLD compared to PitNET patients with normal IGF-1(log-rank test, P < 0.001). In the adjusted Cox regression analysis model (model IV), compared with participants with normal IGF-1, the HRs of those with elevated and reduced IGF-1 were 2.33 (95% CI 1.75, 3.11) and 2.2 (95% CI 1.78, 2.7). Furthermore, in non-adjusted or adjusted models, our study revealed a U-shaped relationship between lgIGF-1 and the risk of NAFLD. Moreover, the results from subgroup and sensitivity analyses were consistent with the main results.

Conclusions

There was a U-shaped trend between IGF-1 and new-onset NAFLD in patients with PitNET. Further evaluation of our discoveries is warranted.

Blockade of angiotensin II modulates insulin-like growth factor 1-mediated skeletal muscle homeostasis in experimental steatohepatitis

Sarcopenia is associated with mortality in patients with nonalcoholic steatohepatitis (NASH). Angiotensin II receptor blocker (ARB) has been suggested to prevent sarcopenia, but reports on its effect on NASH-derived skeletal muscle atrophy in conjunction with insulin-like growth factor 1 (IGF-1)-mediated muscle homeostasis are few. Our aim was to examine the combined effect of the ARB losartan and IGF-1 replacement on skeletal muscle atrophy in a methionine-choline deficient (MCD) diet-fed murine steatohepatitis model. The MCD-fed mice developed steatohepatitis and skeletal muscle atrophy, as indicated by the reduction of psoas muscle mass and attenuation of forelimb and hindlimb grip strength. Significantly suppressed steatohepatitis and skeletal muscle atrophy was observed after single treatment with ARB or IGF-1, and these effects were augmented after combination treatment. Treatment with ARB and IGF-1 effectively inhibited ubiquitin proteasome-mediated protein degradation by reducing forkhead box protein O1 (FOXO1) and FOXO3a transcriptional activity in the skeletal muscle. Combined ARB and IGF-1 decreased the intramuscular expression of proinflammatory cytokines (i.e., TNFα, IL6, and IL1β) and increased the Trolox equivalent antioxidant capacity and antioxidant enzymes (CAT, GPX1, SOD2, and CYTB). This antioxidant effect was based on downregulation of NADPH oxidase (NOX) 2, normalization of mitochondrial biogenesis and dynamics. Moreover, ARB increased the hepatic and plasma IGF-1 levels and improved steatohepatitis, leading to enhanced skeletal muscle protein synthesis mediated by IGF-1/ AKT/ mechanistic target of rapamycin signaling. Collectively, combined ARB and IGF-1 replacement could be a promising new therapeutic target for NASH-derived skeletal muscle wasting.

Research Progress of Aging-related MicroRNAs

Senescence refers to the irreversible state in which cells enter cell cycle arrest due to internal or external stimuli. The accumulation of senescent cells can lead to many age-related diseases, such as neurodegenerative diseases, cardiovascular diseases, and cancers. MicroRNAs are short non-coding RNAs that bind to target mRNA to regulate gene expression after transcription and play an important regulatory role in the aging process. From nematodes to humans, a variety of miRNAs have been confirmed to alter and affect the aging process. Studying the regulatory mechanisms of miRNAs in aging can further deepen our understanding of cell and body aging and provide a new perspective for the diagnosis and treatment of aging-related diseases. In this review, we illustrate the current research status of miRNAs in aging and discuss the possible prospects for clinical applications of targeting miRNAs in senile diseases.

Effects and potential mechanisms of IGF1/IGF1R in the liver fibrosis: A review

Liver fibrosis is a wound-healing response due to persistent liver damage and it may progress to cirrhosis and even liver cancer if no intervention is given. In the current cognition, liver fibrosis is reversible. So, it is of great significance to explore the related gene targets or biomarker for anti-fibrosis of liver. Insulin like growth factor 1 (IGF1) and IGF1 receptor (IGF1R) are mainly expressed in the liver tissues and play critical roles in the liver function. The present review summarized the role of IGF1/IGF1R and its signaling system in liver fibrosis and illustrated the potential mechanisms including DNA damage repair, cell senescence, lipid metabolism and oxidative stress that may be involved in this process according to the studies on the fibrosis of liver or other organs. In particular, the roles of IGF1 and IGF1R in DNA damage repair were elaborated, including membrane-localized and nucleus-localized IGF1R. In addition, for each of the potential mechanism in anti-fibrosis of liver, the signaling pathways of the IGF1/IGF1R mediated and the cell species in liver acted by IGF1 and IGF1R under different conditions were included. The data in this review will support for the study about the effect of IGF1/IGF1R on liver fibrosis induced by various factors, meanwhile, provide a basis for the study of liver fibrosis to focus on the communications between the different kinds of liver cells.

Progerin, an Aberrant Spliced Form of Lamin A, Is a Potential Therapeutic Target for HGPS

Hutchinson-Gilford progeria syndrome (HGPS) is an extremely rare genetic disorder caused by the mutant protein progerin, which is expressed by the abnormal splicing of the LMNA gene. HGPS affects systemic levels, with the exception of cognition or brain development, in children, showing that cellular aging can occur in the short term. Studying progeria could be useful in unraveling the causes of human aging (as well as fatal age-related disorders). Elucidating the clear cause of HGPS or the development of a therapeutic medicine could improve the quality of life and extend the survival of patients. This review aimed to (i) briefly describe how progerin was discovered as the causative agent of HGPS, (ii) elucidate the puzzling observation of the absence of primary neurological disease in HGPS, (iii) present several studies showing the deleterious effects of progerin and the beneficial effects of its inhibition, and (iv) summarize research to develop a therapy for HGPS and introduce clinical trials for its treatment.

Hepatocyte Ninjurin2 promotes hepatic stellate cell activation and liver fibrosis through the IGF1R/EGR1/PDGF-BB signaling pathway

BACKGROUND

Liver fibrogenesis is orchestrated by the paracrine signaling interaction between several resident cell types regulating the activation of hepatic stellate cells (HSCs). However, the molecular mechanisms underlying paracrine regulation are largely unknown. The aim of this study is to elucidate the role of Ninjurin2 in the crosstalk between hepatocytes and HSCs and better understand the implications of Ninjurin2 in liver fibrosis.

METHODS

Ninj2 knockout mice (Ninj2^-/-) and hepatocyte-specific Ninj2 overexpression mice (Ninj2^Hep-tg) were constructed and followed by the induction of liver fibrosis using methionine- and choline-deficient (MCD) diet. The relationship between Ninjurin2 and liver fibrosis phenotype was evaluated in vivo by measurement of fibrotic markers and related genes. We used an in vitro transwell cell co-culture model to examine the impact of Ninjurin2 in hepatocytes on the crosstalk to HSCs. The interaction of Ninjurin2 and IGF1R and the regulation of PI3K-AKT-EGR1 were analyzed in vivo and in vitro. Finally, an inhibitory Ninjurin2 peptide was injected intravenously via the tail vein to investigate whether inhibiting of Ninjurin2 cascade can attenuate MCD diet-induced liver fibrosis in mice.

RESULTS

We found that hepatic Ninjurin2 expression was significantly increased in fibrotic human liver and MCD diet-induced liver injury mouse models. In the mouse model, hepatocyte-specific overexpression of Ninj2 exacerbates MCD-induced liver fibrosis, while global Ninj2 knockout reverses the phenotype. To mimic hepatocyte-HSC crosstalk during liver fibrosis, we used co-culture systems containing hepatocytes and HSCs and determined that Ninjurin2 overexpression in hepatocytes directly activates HSCs in vitro. Mechanistically, Ninjurin2 directly interacts with insulin-like growth factor 1 receptor (IGF1R) and increases the hepatocyte secretion of the fibrogenic cytokine, platelet-derived growth factor-BB (PDGF-BB) through IGF1R-PI3K-AKT-EGR1 cascade. Inhibition of PDGFRB signaling in HSCs can abolish the profibrogenic effect of Ninjurin2. In addition, we demonstrated that a specific inhibitory Ninjurin2 peptide containing an N-terminal adhesion motif mitigates liver fibrosis and improves hepatic function in the mouse models by negatively regulating the sensitivity of IGF1R to IGF1 in hepatocytes.

CONCLUSION

Hepatic Ninjurin2 plays a key role in liver fibrosis through paracrine regulation of PDGF-BB/PDGFRB signaling in HSCs, and the results suggesting Ninjurin2 may be a potential therapeutic target.

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.

Nucleophagic Degradation of Progerin Ameliorates Defenestration in Liver Sinusoidal Endothelium Due to SIRT1-Mediated Deacetylation of Nuclear LC3

Progerin, a permanently farnesylated prelamin A protein in cell nuclei, is potentially implicated in the defenestration of liver sinusoidal endothelial cells (LSECs) and liver fibrogenesis. Autophagy regulates the degradation of nuclear components, called nucleophagy, in response to damage. However, little is known about the role of nucleophagy in LSEC defenestration. Herein, we aim to dissect the underlying mechanism of progerin and nucleophagy in LSEC phenotype. We found an abnormal accumulation of progerin and a loss of SIRT1 in the nucleus of intrahepatic cells in human fibrotic liver tissue. In vivo, nuclear progerin abnormally accumulated in defenestrated LSECs, along with a depletion of SIRT1 and Cav-1 during liver fibrogenesis, whereas these effects were reversed by the overexpression of SIRT1 with the adenovirus vector. In vitro, H₂O₂ induced the excessive accumulation of progeirn, with the depletion of Lamin B1 and Cav-1 to aggravate LSEC defenestration. NAC and mito-TEMPO, classical antioxidants, inhibited NOX2- and NOX4-dependent oxidative stress to improve the depletion of Lamin B1 and Cav-1 and promoted progerin-related nucleophagy, leading to a reverse in H₂O₂-induced LSEC defenestration. However, rapamycin aggravated the H₂O₂-induced depletion of Lamin B1 and Cav-1 due to excessive autophagy, despite promoting progerin nucleophagic degradation. In addition, overexpressing SIRT1 with the adenovirus vector inhibited oxidative stress to rescue the production of Lamin B1 and Cav-1. Moreover, the SIRT1-mediated deacetylation of nuclear LC3 promoted progerin nucleophagic degradation and subsequently inhibited the degradation of Lamin B1 and Cav-1, as well as improved F-actin remodeling, contributing to maintaining LSEC fenestrae. Hence, our findings indicate a new strategy for reversing LSEC defenestration by promoting progerin clearance via the SIRT1-mediated deacetylation of nuclear LC3.

Covert actions of growth hormone: fibrosis, cardiovascular diseases and cancer

Since its discovery nearly a century ago, over 100,000 studies of growth hormone (GH) have investigated its structure, how it interacts with the GH receptor and its multiple actions. These include effects on growth, substrate metabolism, body composition, bone mineral density, the cardiovascular system and brain function, among many others. Recombinant human GH is approved for use to promote growth in children with GH deficiency (GHD), along with several additional clinical indications. Studies of humans and animals with altered levels of GH, from complete or partial GHD to GH excess, have revealed several covert or hidden actions of GH, such as effects on fibrosis, cardiovascular function and cancer. In this Review, we do not concentrate on the classic and controversial indications for GH therapy, nor do we cover all covert actions of GH. Instead, we stress the importance of the relationship between GH and fibrosis, and how fibrosis (or lack thereof) might be an emerging factor in both cardiovascular and cancer pathologies. We highlight clinical data from patients with acromegaly or GHD, alongside data from cellular and animal studies, to reveal novel phenotypes and molecular pathways responsible for these actions of GH in fibrosis, cardiovascular function and cancer.

Oxidative stress-induced premature senescence and aggravated denervated skeletal muscular atrophy by regulating progerin-p53 interaction

Background

Progerin elevates atrophic gene expression and helps modify the nuclear membrane to cause severe muscle pathology, which is similar to muscle weakness in the elderly, to alter the development and function of the skeletal muscles. Stress-induced premature senescence (SIPS), a state of cell growth arrest owing to such stimuli as oxidation, can be caused by progerin. However, evidence for whether SIPS-induced progerin accumulation is connected to denervation-induced muscle atrophy is not sufficient.

Methods

Flow cytometry and a reactive oxygen species (ROS) as well as inducible nitric oxide synthase (iNOS) inhibitors were used to assess the effect of oxidation on protein (p53), progerin, and nuclear progerin–p53 interaction in the denervated muscles of models of mice suffering from sciatic injury. Loss-of-function approach with the targeted deletion of p53 was used to assess connection among SIPS, denervated muscle atrophy, and fibrogenesis.

Results

The augmentation of ROS and iNOS-derived NO in the denervated muscles of models of mice suffering from sciatic injury upregulates p53 and progerin. The abnormal accumulation of progerin in the nuclear membrane as well as the activation of nuclear progerin–p53 interaction triggered premature senescence in the denervated muscle cells of mice. The p53-dependent SIPS in denervated muscles contributes to their atrophy and fibrogenesis.

Conclusion

Oxidative stress-triggered premature senescence via nuclear progerin–p53 interaction that promotes denervated skeletal muscular atrophy and fibrogenesis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13395-022-00302-y.

Paracrine IGF-1 Activates SOD2 Expression and Regulates ROS/p53 Axis in the Treatment of Cardiac Damage in D-Galactose-Induced Aging Rats after Receiving Mesenchymal Stem Cells

Aging is one of the causative agents associated with heart failure. Cell-based therapies show potential in the treatment of cardiac aging due to the characteristics of stem cells, including differentiation and the paracrine effect. This study aimed to investigate in detail the mechanism related to biomolecules released from mesenchymal stem cells in the treatment of cardiac aging. In vitro and in vivo models were designed to explore the above hypothesis. Experimental results from the in vitro model indicated that the elevation of oxidative stress, the expression of aging marker p53, and the suppression of antioxidant marker SOD2 could be found in D-galactose-stressed H9c2 cardiomyoblasts. The co-culture of D-galactose-stressed H9c2 with mesenchymal stem cells significantly improved the above pathological signaling. An animal model revealed that the change in cardiac structure, the accumulation of fibrotic collagen, and the activation of the above pathological signaling could be observed in heart tissues of D-galactose-stressed rats. After the rats had received mesenchymal stem cells, all the pathological conditions were significantly improved in D-galactose-stressed hearts. Further evidence indicated that the release of the survival marker IGF-1 was detected in a stem-cell-conditioned medium. Significant increases in cell viability and the expression of SOD2, as well as a reduction in oxidative stress and the suppression of p53, were found in D-galactose-stressed H9c2 cells cultured with a stem-cell-conditioned medium, whereas the depletion of IGF-1 in stem-cell-conditioned medium diminished the antiaging effect on H9c2 cells. In conclusion, the paracrine release of IGF-1 from mesenchymal stem cells increases the expression of antioxidant marker SOD2, and the expression of SOD2 reduces oxidative stress as well as suppresses p53, leading to a reduction in cardiac senescence in D-galactose-stressed rats.

Ageing - Oxidative stress, PTMs and disease

Post-translational modifications (PTMs) have been proposed as a link between the oxidative stress-inflammation-ageing trinity, thereby affecting several hallmarks of ageing. Phosphorylation, acetylation, and ubiquitination cover >90% of all the reported PTMs. Several of the main PTMs are involved in normal "healthy" ageing and in different age-related diseases, for instance neurodegenerative, metabolic, cardiovascular, and bone diseases, as well as cancer and chronic kidney disease. Ultimately, data from human rare progeroid syndromes, but also from long-living animal species, imply that PTMs are critical regulators of the ageing process. Mechanistically, PTMs target epigenetic and non-epigenetic pathways during ageing. In particular, epigenetic histone modification has critical implications for the ageing process and can modulate lifespan. Therefore, PTM-based therapeutics appear to be attractive pharmaceutical candidates to reduce the burden of ageing-related diseases. Several phosphorylation and acetylation inhibitors have already been FDA-approved for the treatment of other diseases and offer a unique potential to investigate both beneficial effects and possible side-effects. As an example, the most well-studied senolytic compounds dasatinib and quercetin, which have already been tested in Phase 1 pilot studies, also act as kinase inhibitors, targeting cellular senescence and increasing lifespan. Future studies need to carefully determine the best PTM-based candidates for the treatment of the "diseasome of ageing".

Mannan-Binding Lectin via Interaction With Cell Surface Calreticulin Promotes Senescence of Activated Hepatic Stellate Cells to Limit Liver Fibrosis Progression

BACKGROUND & AIMS

Liver fibrosis represents a hallmark of most chronic liver diseases (CLD) triggered by recurrent liver injury and subsequent myofibroblast transdifferentiations of resident hepatic stellate cells (HSCs). Mannan-binding lectin (MBL) is potentially involved in hepatic fibrosis in CLD through unclear mechanisms. Therefore, we investigated the crosstalk between MBL and HSCs, and the consequent effects on fibrosis progression.

METHODS

Samples from patients with liver cirrhosis were collected. MBL deficiency (MBL-/-) and wild-type (WT) C57BL/6J mice were used to construct a CCl4-induced liver fibrosis model. Administration of MBL-expressing, liver-specific, adeno-associated virus was performed to restore hepatic MBL expression in MBL-/- mice. The human HSC line LX-2 was used for in vitro experiments.

RESULTS

MBL levels in patients with liver cirrhosis were correlated with disease severity. In the CCl4-induced liver fibrosis model, MBL-/- mice showed severer liver fibrosis accompanied by reduced senescent activated HSCs in liver tissue compared with WT mice, which could be inhibited by administering MBL-expressing, liver-specific, adeno-associated virus. Moreover, depleting senescent cells with senolytic treatment could abrogate these differences owing to MBL absence. Furthermore, MBL could interact directly with calreticulin associated with low-density lipoprotein receptor-related protein 1 on the cell surface of HSCs, which further promotes senescence in HSCs by up-regulating the mammalian target of rapamycin/p53/p21 signaling pathway.

CONCLUSIONS

MBL as a newfound senescence-promoting modulator and its crosstalk with HSCs in the liver microenvironment is essential for the control of hepatic fibrosis progression, suggesting its potential therapeutic use in treating CLD associated with liver fibrosis.

Regulation of Cr(VI)-Induced Premature Senescence in L02 Hepatocytes by ROS-Ca2+-NF-κB Signaling

Stress-induced premature senescence may be involved in the pathogeneses of acute liver injury. Hexavalent chromium [Cr(VI)], a common environmental pollutant related to liver injury, likely leads to premature senescence in L02 hepatocytes. However, the underlying mechanisms regarding hepatocyte premature senility in Cr(VI) exposure remain poorly understood. In this study, we found that chronic exposure of L02 hepatocytes to Cr(VI) led to premature senescence characterized by increased β-galactosidase activity, senescence-associated heterochromatin foci, G1 phase arrest, and decreased cell proliferation. Additionally, Cr(VI)-induced senescent L02 hepatocytes showed upregulated inflammation-related factors, such as IL-6 and fibroblast growth factor 23 (FGF23), which also exhibited reactive oxygen species (ROS) accumulation derived from mitochondria accompanied with increased concentration of intracellular calcium ions (Ca²⁺) and activity of nuclear factor kappa B (NF-κB). Of note is that ROS inhibition by N-acetyl-Lcysteine pretreatment not only alleviated Cr(VI)-induced premature senescence but also reduced the elevated intracellular Ca²⁺, activated NF-κB, and secretion of IL-6/FGF23. Intriguingly, the toxic effect of Cr(VI) upon premature senescence of L02 hepatocytes and increased levels of IL-6/FGF23 could be partially reversed by the intracellular Ca²⁺ chelator BAPTA-AM pretreatment. Furthermore, by utilizing the NF-κB inhibitor pyrrolidine dithiocarbamate (PDTC), we confirmed that NF-κB mediated IL-6/FGF23 to regulate the Cr(VI)-induced L02 hepatocyte premature senescence, whilst the concentration of intracellular Ca²⁺ was not influenced by PDTC. To the best of our knowledge, our data reports for the first time the role of ROS-Ca²⁺-NF-κB signaling pathway in Cr(VI)-induced premature senescence. Our results collectively shed light on further exploration of innovative intervention strategies and treatment targeting Cr(VI)-induced chronic liver damage related to premature senescence.

IGF-1 alleviates CCL4-induced hepatic cirrhosis and dysfunction of intestinal barrier through inhibition TLR4/NF-κB signaling mediated by down-regulation HMGB1

INTRODUCTION AND OBJECTIVES

Cirrhosis has gradually become a serious public health issue, especially the national prevalence of cirrhosis was 29.2% in northwest China. Recent evidence has revealed that intestinal barrier (IB) dysfunction results from and contributes to cirrhosis. Our previous results have indicated that insulin-like growth factors (IGF-1) improved the impaired IB function and downregulated high mobility group protein box-1 (HMGB-1). Nevertheless, the role of the IGF-1/HMGB1 axis in cirrhosis remains largely unknown.

MATERIALS AND METHODS

Western blotting and qRT-PCR were used to detect protein and mRNA levels of related genes. The levels of AST, ALT, IL-1β, and TNF-α were examined using commercial kits. Immunofluorescence was used to evaluate the expression of HMGB1 in tissues.

RESULTS

In carbon tetrachloride (CCl4)-treated rat, the levels of AST (380.12 vs. 183.97), ALT (148.12 vs. 53.56), IL-1β (155.94 vs. 55.60), and TNF-α (155.00 vs. 48.90) were significantly increased compared with the control group, while IGF-1 treatment significantly alleviated CCL4-induced inflammatory response and IB dysfunction by downregulating HMGB1-mediated the TLR4/MyD88/NF-κB signaling pathway. In vitro experiments, HMGB1 treatment promoted inflammatory cytokines secretion and reduced cell viability and tight junctions by activating the TLR4/MyD88/NF-κB signaling pathway in Caco-2 cells, but IGF-1 alleviated these effects.

CONCLUSION

Our findings suggest that IGF-1 might serve as a potential therapeutic target for cirrhosis and IB dysfunction via inactivation of the TLR4/MyD88/NF-κB pathway through down-regulation HMGB1.

Insight into the Protective Effect of Salidroside against H2O2-Induced Injury in H9C2 Cells

Salidroside is the important active ingredient of Rhodiola species, which shows a wide range of pharmacological activities such as antioxidative stress, anti-inflammation, and antiliver fibrosis. In this paper, we aimed to study the protective effect and mechanism of salidroside against H2O2-induced oxidative damage in H9C2 cells by determining cell proliferation rate, intracellular reactive oxygen species (ROS) level, antioxidant enzyme activities, and the expression of apoptosis-related proteins. The results showed that salidroside significantly alleviated cell growth inhibition induced by H2O2 treatment in H9C2 cells, decreased the levels of intracellular ROS and malondialdehyde (MDA), and increased the activity of superoxide dismutase (SOD) and catalase (CAT); meanwhile, salidroside upregulated the expression of Bcl-2 while downregulated the expression of Bax, p53, and caspase-3 in H2O2-treated H9C2 cells. Furthermore, the antiapoptotic effect of salidroside was almost eliminated by the knockdown of Bcl-2. In the further exploration, the Bcl-2 expression was decreased by the p53 overexpression and increased by p53 knockdown in H2O2-treated H9C2 cells. Consequently, salidroside could protect H9C2 cells against H2O2-induced oxidative damage, and the underlying mechanism may be related to scavenging intracellular ROS, increasing the activities of intracellular antioxidant enzymes and inhibiting the expression of apoptosis-related proteins.

Effects of Silver Nanoparticles and Silver Nitrate on mRNA and microRNA Expression in Human Hepatocellular Carcinoma Cells (HepG2)

In order to understand toxicity of nano silver, human hepatocellular carcinoma (HepG2) cells were treated either with silver nitrate (AgNO₃) or with nano silver capped with glutathione (Ag-S) at various concentration. Differentially expressed genelists for mRNA and microRNA were obtained through Illumina RNA sequencing and DEseq data analyses. Both treatments showed non-linear dose response relationships for mRNA and microRNA. Gene expression analysis showed signaling pathways common to both nano Ag-S and AgNO₃, such as cell cycle regulation, DNA damage response and cancer related pathways. But, nano Ag-S caused signaling pathway changes that were not altered by AgNO₃ such as NRF2-mediated oxidative stress response inflammation, cell membrane signaling, and cell proliferation. Nano Ag-S also affected p53 signaling, survival, apoptosis, tissue repair, lipid synthesis, angiogenesis, liver fibrosis and tumor development. Several of the pathways affected by nano Ag-S are hypothesized as major contributors to nanotoxicity. MicroRNA target filter analysis revealed additional affected pathways that were not reflected in the mRNA expression response alone, including DNA damage signaling, genomic stability, ROS, cell cycle, ubiquitination, DNA methylation, cell proliferation and fibrosis for AgNO₃; and cell cycle regulation, P53 signaling, cell proliferation, survival, apoptosis, tissue repair and so on for nano Ag-S. These pathways may be mediated by microRNA repression of protein translation.Our study clearly showed that the addition of microRNA profiling increased the numbers of signaling pathways discovered that affected by the treatments on HepG2 cells and gave US a better picture of the effects of these reagents in the cells.

The Effect of Oxidative Stress on the Chicken Ovary: Involvement of Microbiota and Melatonin Interventions

The poultry ovary is used as a classic model to study ovarian biology and ovarian cancer. Stress factors induced oxidative stress to cause follicle atresia, which may be a fundamental reason for the reduction in fertility in older laying hens or in aging women. In the present study, we set out to characterize the relationships between oxidative stress and ovarian function. Layers (62 weeks of age; BW = 1.42 ± 0.12 kg) were injected with tert-butyl hydroperoxide (tBHP) at 0 (CON) and 800 μmol/kg BW (oxidative stress group, OS) for 24 days and the role of melatonin (Mel) on tBHP-induced ovary oxidative stress was assessed through ovary culture in vitro. The OS (800 μmol/kg BW tert-butyl hydroperoxide) treatment decreased the reproduction performance and ovarian follicle numbers. OS decreased the expression of SIRT1 and increased the P53 and FoxO1 expression of the ovary. A decreased Firmicutes to Bacteroidetes ratio, enriched Marinifilaceae (family), Odoribacter (genus) and Bacteroides_plebeius (species) were observed in the cecum of the OS group. Using Mel in vitro enhanced the follicle numbers and decreased the ovary cell apoptosis induced by tBHP. In addition, it increased the expression of SIRT1 and decreased the P53 and FoxO1 expression. These findings indicated that oxidative stress could decrease the laying performance, ovarian function and influence gut microbiota and body metabolites in the layer model, while the melatonin exerts an amelioration the ovary oxidative stress through SIRT1-P53/FoxO1 pathway.

Lack of Mof reduces acute liver injury by enhancing transcriptional activation of Igf1

Acute liver injury (ALI) is a rapid pathological process that may cause severe liver disease and may even be life-threatening. During ALI, the function of males absent on the first (MOF) has not yet been elucidated. In this study, we unveiled the expression pattern of MOF during carbon tetrachloride (CCl4 )-induced ALI and role of MOF in the regulation of liver regeneration. In the process of ALI, MOF is significantly overexpressed in the liver injury area. Knockdown of Mof attenuated CCl4 -induced ALI, and promoted liver cell proliferation, hepatic stellate cell activation and aggregation to the injured area, and liver fibrosis. Simultaneously, overexpression of Mof aggravated liver dysfunction caused by ALI. By directly binding to the promoter, MOF suppressed the transcriptional activation of Igf1. Knockdown of Mof promotes the expression of Igf1 and activates the Insulin-like growth factor 1 signaling pathway in the liver. Through this pathway, Knockdown of Mof reduces CCl4 -induced ALI and promotes liver regeneration. Our results provide the first demonstration for MOF contributing to ALI. Further understanding of the role of MOF in ALI may lead to new therapeutic strategies for ALI.

ASCs -derived exosomes loaded with vitamin A and quercetin inhibit rapid senescence-like response after acute liver injury

Acute liver injury is a short-term burst of liver cell damage, which has many causes and complex mechanisms. Despite the unique ability of the liver to heal itself, there is still no effective treatment except liver transplantation for chronic liver injury or even liver failure caused by acute liver injury. Stem cell-derived exosomes are ideal drug carriers due to their unique immunomodulatory effects and structural characteristics. In this study, quercetin and vitamin A loaded adipose mesenchymal stem cells (ASCs)-derived exosomes were constructed and used to treat acute liver injury induced by CCl4 in mice. Quercetin enhances the therapeutic efficacy of exosomes, while vitamin A enhances the liver targeting of exosomes, and it was found that quercetin and vitamin A loaded mesenchymal stem cell exosomes reduce rapid senescence-like response induced by acute liver injury.

Alpha lipoic acid priming enhances the hepatoprotective effect of adipose derived stem cells in CCl4 induced hepatic injury in-vitro

Mesenchymal stem cells are known to support hepatic defense against liver fibrosis. However, the fibrosis induced oxidative microenvironment affects the proliferative, regenerative, and angiogenic properties of mesenchymal stem cells. Alpha lipoic acid (ALA) is a strong anti-oxidant which has been shown to ameliorate the adverse effects of fibrosis that otherwise can lead to severe liver problems like cirrhosis and liver failure. Here, we studied the protective role of ALA primed adipose derived stem cells (ADSCs) against carbon tetrachloride (CCl₄₎ induced hepatotoxicity in primary hepatocytes in-vitro. Priming of ADSCs helped to abrogate the damaging effects of fibrosis induced oxidative stress as evidenced by significantly reduced levels of alkaline phosphatase (ALP), Alanine Aminotransferase (ALAT) along with decreased lactate dehydrogenase (LDH) release and improved superoxide dismutase (SOD) activity. ALA and ADSCs synergistically down-regulated the expression of Bax gene, an apoptosis regulator while enhancing cell proliferation by up-regulating the expression of Bcl2l1 gene. This treatment improved the expression of albumin (Alb), cytokeratin-8 (Ck8), and hepatic nuclear factor alpha (Hnf4α). Cytochrome P450 2E1 (Cyp2e1) and Alpha fetoprotein (Afp) were down-regulated to lessen the damage caused by CCl₄ treatment. Furthermore, paracrine release of several growth factors like hepatocyte growth factor (HGF), vascular endothelial growth factor (VEGF), interleukin-6 (IL-6), tumor necrosis factor alpha (TNFα), and insulin growth factor (IGF) reinforced the improved response of primary hepatocytes against CCl₄ induced hepatotoxicity in the presence of ALA primed ADSCs. This study suggests that ALA priming may improve the therapeutic potential of ADSCs against chronic liver problems by activating the nuclear factor erythroid 2-related factor 2 (Nrf2) and its downstream antioxidant factors heme oxygenase 1 (HO-1) and quinone acceptor oxidoreductase-1 (NQO1).

Insulin Resistance across the Spectrum of Nonalcoholic Fatty Liver Disease

Insulin resistance (IR) is defined as a lower-than-expected response to insulin action from target tissues, leading to the development of type 2 diabetes through the impairment of both glucose and lipid metabolism. IR is a common condition in subjects with nonalcoholic fatty liver disease (NAFLD) and is considered one of the main factors involved in the pathogenesis of nonalcoholic steatohepatitis (NASH) and in the progression of liver disease. The liver, the adipose tissue and the skeletal muscle are major contributors for the development and worsening of IR. In this review, we discuss the sites and mechanisms of insulin action and the IR-related impairment along the spectrum of NAFLD, from simple steatosis to progressive NASH and cirrhosis.

Sirtuin 1 ameliorates defenestration in hepatic sinusoidal endothelial cells during liver fibrosis via inhibiting stress-induced premature senescence

OBJECTIVE

Premature senescence is related to progerin and involves in endothelial dysfunction and liver diseases. Activating sirtuin 1 (SIRT1) ameliorates liver fibrosis. However, the mechanisms of premature senescence in defenestration of hepatic sinusoidal endothelial cells (HSECs) and how SIRT1 affects HSECs fenestrae remain elusive.

METHODS

We employed the CCl4 -induced liver fibrogenesis rat models and cultured primary HSECs in vitro, administered with the SIRT1-adenovirus vector, the activator of SIRT1 and knockdown NOX2. We measured the activity of senescence-associated β-galactosidase (SA-β-gal) in HSECs. Meanwhile, the protein expression of SIRT1, NOX2, progerin, Lamin A/C, Ac p53 K381 and total p53 was detected by Western blot, co-immunoprecipitation and immunofluorescence.

RESULTS

In vivo, premature senescence was triggered by oxidative stress during CCl4 -induced HSECs defenestration and liver fibrogenesis, whereas overexpressing SIRT1 with adenovirus vector lessened premature senescence to relieve CCl4 -induced HSECs defenestration and liver fibrosis. In vitro, HSECs fenestrae disappeared, with emerging progerin-associated premature senescence; these effects were aggravated by H2 O2 . Nevertheless, knockdown of NOX2, activation of SIRT1 with resveratrol and SIRT1-adenovirus vector inhibited progerin-associated premature senescence to maintain fenestrae through deacetylating p53. Furthermore, more Ac p53 K381 and progerin co-localized with the abnormal accumulation of actin filament (F-actin) in the nuclear envelope of H2 O2 -treated HSECs; in contrast, these effects were rescued by overexpressing SIRT1.

CONCLUSION

SIRT1-mediated deacetylation maintains HSECs fenestrae and attenuates liver fibrogenesis through inhibiting oxidative stress-induced premature senescence.

The Dynamic Inflammatory Tissue Microenvironment: Signality and Disease Therapy by Biomaterials

Tissue regeneration is an active multiplex process involving the dynamic inflammatory microenvironment. Under a normal physiological framework, inflammation is necessary for the systematic immunity including tissue repair and regeneration as well as returning to homeostasis. Inflammatory cellular response and metabolic mechanisms play key roles in the well-orchestrated tissue regeneration. If this response is dysregulated, it becomes chronic, which in turn causes progressive fibrosis, improper repair, and autoimmune disorders, ultimately leading to organ failure and death. Therefore, understanding of the complex inflammatory multiple player responses and their cellular metabolisms facilitates the latest insights and brings novel therapeutic methods for early diseases and modern health challenges. This review discusses the recent advances in molecular interactions of immune cells, controlled shift of pro- to anti-inflammation, reparative inflammatory metabolisms in tissue regeneration, controlling of an unfavorable microenvironment, dysregulated inflammatory diseases, and emerging therapeutic strategies including the use of biomaterials, which expand therapeutic views and briefly denote important gaps that are still prevailing.

Vitamin E pretreated Wharton's jelly-derived mesenchymal stem cells attenuate CCl4-induced hepatocyte injury in vitro and liver fibrosis in vivo

Oxidative microenvironment in fibrotic liver alleviates the efficacious outcome of mesenchymal stem cells (MSCs)-based cell therapy. Recent evidence suggests that pharmacological pretreatment is a rational approach to harness the MSCs with higher therapeutic potential. Here, we investigated whether Vitamin E pretreatment can boost the antifibrotic effects of Wharton's jelly-derived MSCs (WJMSCs). We used rat liver-derived hepatocytes injured by CCl₄ treatment in co-culture system with Vitamin E pretreated-WJMSCs (Vit E-WJMSCs) to evaluate the hepatoprotective effect of Vit E-WJMSCs. After 24 h of co-culturing, we found that Vit E-WJMSCs rescued injured hepatocytes as hepatocyte injury-associated medium (AST, ALT, and ALP) and mRNA (Cyp2e1, Hif1-α, and Il-1β) markers reduced to normal levels. Subsequently, CCl₄-induced liver fibrosis rat models were employed to examine the antifibrotic potential of Vit E-WJMSCs. After 1 month of cell transplantation, it was revealed that Vit E-WJMSCs transplantation ceased fibrotic progression, as evident by improved hepatic architecture and functions, more significantly in comparison to naïve WJMSCs. In addition, Vit E-WJMSCs transplantation decreased the expressions of fibrosis-associated gene (Tgf-β1, α-Sma, and Col1α1) markers in the liver parenchyma. Intriguingly, the results of tracing experiments discovered that more WJMSCs engrafted in the Vit E-WJMSCs treated rat livers compared to naïve WJMSCs treated livers. These findings implicate that pretreatment of WJMSCs with Vitamin E improves their tolerance to hostile niche of fibrotic liver; thereby further enhancing their efficacy for hepatic fibrosis.

Relationship of IGF-1 and IGF-Binding Proteins to Disease Severity and Glycemia in Nonalcoholic Fatty Liver Disease

CONTEXT

Growth hormone (GH) and IGF-1 help regulate hepatic glucose and lipid metabolism, and reductions in these hormones may contribute to development of nonalcoholic fatty liver disease (NAFLD).

OBJECTIVE

To assess relationships between hepatic expression of IGF1 and IGF-binding proteins (IGFBPs) and measures of glycemia and liver disease in adults with NAFLD. Secondarily to assess effects of GH-releasing hormone (GHRH) on circulating IGFBPs.

DESIGN

Analysis of data from a randomized clinical trial of GHRH.

SETTING

Two US academic medical centers.

PARTICIPANTS

Participants were 61 men and women 18 to 70 years of age with HIV-infection, ≥5% hepatic fat fraction, including 39 with RNA-Seq data from liver biopsy.

MAIN OUTCOME MEASURES

Hepatic steatosis, inflammation, and fibrosis by histopathology and measures of glucose homeostasis.

RESULTS

Hepatic IGF1 mRNA was significantly lower in individuals with higher steatosis and NAFLD Activity Score (NAS) and was inversely related to glucose parameters, independent of circulating IGF-1. Among the IGFBPs, IGFBP2 and IGFBP4 were lower and IGFBP6 and IGFBP7 (also known as IGFBP-related protein 1) were higher with increasing steatosis. Hepatic IGFBP6 and IGFBP7 mRNA levels were positively associated with NAS. IGFBP7 mRNA increased with increasing fibrosis. Hepatic IGFBP1 mRNA was inversely associated with glycemia and insulin resistance, with opposite relationships present for IGFBP3 and IGFBP7. GHRH increased circulating IGFBP-1 and IGFBP-3, but decreased IGFBP-2 and IGFBP-6.

CONCLUSIONS

These data demonstrate novel relationships of IGF-1 and IGFBPs with NAFLD severity and glucose control, with divergent roles seen for different IGFBPs. Moreover, the data provide new information on the complex effects of GHRH on IGFBPs.

Immunohistochemical expression of insulin-like growth factor-1Ec in primary endometrial carcinoma: Association with PTEN, p53 and survivin expression

Chronic hyperinsulinemia due to insulin resistance and elevated levels of insulin-like growth factor (IGF)-1 and IGF-2 are suggestive of a significantly higher risk of endometrial carcinoma. There is a wealth of evidence showing differential expression of IGF-1 isoforms in various types of cancer. In the present study, 99 archived endometrial carcinoma tissue sections were retrospectively assessed by immunohistochemistry for IGF-1Ec isoform expression. Expression of IGF-1Ec was also assessed in nine cases of non-neoplastic endometrial tissue adjacent to the tumor, in 30 cases with normal endometrium and in 30 cases with endometrial hyperplasia. Furthermore, the association between IGF-1Ec and the concurrent expression of phosphatase and tensin homologue deleted on chromosome 10 (PTEN), p53 or survivin was assessed, as well as their combined expression in association with clinicopathological variables. In endometrial carcinoma, IGF-1Ec expression was high in non-endometrioid carcinoma (serous papillary or clear cell carcinoma) compared with that in endometrioid adenocarcinoma. IGF-1Ec expression was also high in the presence of tumoral necrosis. Furthermore, there was a significant correlation between the histological differentiation and the sum of staining intensity and the number of IGF-1Ec immunopositive cells in endometrial carcinoma. There was a moderate negative correlation between co-expression of IGF-1Ec and PTEN, for both the number of immunopositive cells (P=0.006, ρ=−0.343) and the sum of staining (scores and intensity; P=0.006, ρ=−0.343). Furthermore, there was a positive correlation between the sum of staining (scores and intensity) and co-expression of IGF-1Ec and survivin (P=0.043, ρ=0.225). However, there was no association between concomitant expression of IGF-1Ec and p53. These results emphasized the importance of IGF-1Ec expression during development of non-estrogen dependent endometrial adenocarcinoma. IGF-1Ec and PTEN may function opposingly during endometrial carcinogenesis. By contrast, IGF-1Ec and survivin may share common molecular pathways and may promote, in parallel, tumoral development.

Hydrogen sulfide is a regulator of mammary gland development in prepubescent female mice

The present study aimed to investigate the effects of exogenous H2S on mammary gland development in pubescent mice and to explore the underlying mechanism. The mouse mammary epithelial cell line HC11, along with C57BL/6J mice, were treated with different concentrations of sodium hydrosulfide (NaHS), which is a donor of H2S. The HC11 cell viability, pubescent mammary gland development, and the involvement of proliferative proteins and pathways were assessed by CCK‑8 assay, EdU assay, whole mount staining, H&E staining, western blotting and reverse transcription‑quantitative PCR. Both in vitro and in vivo, a low concentration of NaHS (100 µM in vitro; 9 mg/kg in vivo) significantly promoted the viability of HC11 cells and the development of mammary glands by increasing the expression of the proliferative markers cyclin D1/3 and proliferating cell nuclear antigen. However, a high concentration of NaHS (1,000 µM in vitro; 18 mg/kg in vivo) inhibited HC11 cell viability, mammary gland development and the expression levels of proteins involved in proliferation. Subsequent experiments revealed that NaHS regulated the phosphatidylinositol 3‑kinase (PI3K)/protein kinase B (Akt)‑mammalian target of rapamycin (mTOR) signaling pathway during this process. In vivo, intraperitoneal injection of low concentration NaHS (9 mg/kg) activated the PI3K/Akt‑mTOR pathway in mammary glands of pubescent mice, increased the secretion of insulin‑like growth factor 1 (IGF‑1) and estradiol (E2), and then stimulated mammary gland ductal development. Whereas a high concentration of NaHS (18 mg/kg) elicited the opposite effects to those of low‑dose NaHS. In conclusion, the present study demonstrated that exogenous H2S supplied by NaHS may exert bidirectional effects on mammary gland ductal development; promoting ductal development at a low concentration and inhibiting it at a high concentration. The effects of H2S may occur via the intracellular PI3K/Akt‑mTOR signaling pathway, or by regulation of the secretion of IGF‑1 and E2.

MiR-483 induces senescence of human adipose-derived mesenchymal stem cells through IGF1 inhibition

Human adipose-derived mesenchymal stem cells (hADSCs) are an ideal source of seed cells for regenerative applications and tissue engineering. However, long-term in vitro culture of hADSCs reduces their quantity and quality, which lessens their value in research and clinical applications. The molecular mechanisms underlying this biological process are poorly defined. Recently identified microRNAs (miRNAs) have emerged as critical modulators of cellular senescence. In this study, we examined the changes in hADSCs undergoing senescence. Significant miR-483-3p upregulation was noted during in vitro passaging of hADSCs, which correlated with the adipogenic differentiation and cellular senescence. Knockdown of miR-483-3p retarded the adipogenic differentiation potential of hADSCs and reduced cellular senescence. Dual-luciferase reporter assays identified insulin-like growth factor-1 (IGF1) as the target gene of miR-483-3p. IGF1 inhibition confirmed its inhibitory effects on replicative senescence in hADSCs. In conclusion, our study revealed essential regulatory roles of miR-483-3p in the adipogenesis and aging of hADSCs mediated by targeting IGF1.

Effects of GH/IGF on the Aging Mitochondria

The mitochondria are key organelles regulating vital processes in the eukaryote cell. A decline in mitochondrial function is one of the hallmarks of aging. Growth hormone (GH) and the insulin-like growth factor-1 (IGF-1) are somatotropic hormones that regulate cellular homeostasis and play significant roles in cell differentiation, function, and survival. In mammals, these hormones peak during puberty and decline gradually during adulthood and aging. Here, we review the evidence that GH and IGF-1 regulate mitochondrial mass and function and contribute to specific processes of cellular aging. Specifically, we discuss the contribution of GH and IGF-1 to mitochondrial biogenesis, respiration and ATP production, oxidative stress, senescence, and apoptosis. Particular emphasis was placed on how these pathways intersect during aging.

Senescence-associated miR-34a and miR-126 in middle-aged Indians with type 2 diabetes

Rapid urbanization and unhealthy dietary patterns critically increase the risk of type 2 diabetes (T2D) in middle-aged Indians. However, despite recent evidence of senescence-associated microRNAs (SA-miRNAs) in regulating complex pathways of ageing, their expressions in middle-aged Indians with T2D remain unexplored. Hence we aimed to investigate the changes in expressions of SA-miRNAs miR-34a and miR-126 in middle-aged T2D patients. A total of 30 T2D patients and 30 controls were recruited of age 31-50 years. The expressions of plasma miR-34a and miR-126 were determined by quantitative PCR. Oxidized LDL (OxLDL) and malondialdehyde (MDA) levels were quantified using enzyme-linked immunosorbent assay (ELISA). The effect of different glucose concentrations on miR-34a, miR-126, senescence-associated, and oxidative stress-responsive genes were also studied in an in vitro model of mice pancreatic β-cells. MiR-34a was significantly upregulated, whereas miR-126 was nonsignificantly reduced in T2D patients as compared to controls. T2D patients showed elevated levels of oxidative stress markers than controls. Analysis of cultured mice pancreatic β-cells exposed to high glucose showed significant upregulation of miR-34a, miR-126, p53, and superoxide dismutase 2 (SOD2). We found that circulating miR-34a levels and oxidative stress markers levels were elevated in the middle-aged Indians with T2D as compared to controls. The presence of diabetes may aggravate the normal ageing process in the middle-aged Indians. These SA-miRNAs can also be used to check the cellular dysfunctions and ageing of pancreatic β-cells.

PAS kinase deficiency reduces aging effects in mice

Several signaling pathways may be affected during aging. All are regulated by nutrient levels leading to a decline in mitochondrial function and autophagy and to an increase in oxidative stress. PAS Domain Kinase (PASK) is a nutrient and bioenergetic sensor. We have previously found that PASK plays a role in the control of hepatic metabolic balance and mitochondrial homeostasis. To investigate PASK’s role in hepatic oxidative stress during aging, we analyzed the mitochondrial function, glucose tolerance, insulin resistance, and lipid-related parameters in aged PASK-deficient mice. Hepatic Pask mRNA decreased in step with aging, being undetectable in aged wild-type (WT) mice. Aged PASK-deficient mice recorded lower levels of ROS/RNS compared to aged WT. The regulators of mitochondrial biogenesis, PGC1a, SIRT1 and NRF2, decreased in aged WT, while aged PASK-deficient mice recorded a higher expression of NRF2, GCLm and HO1 proteins and CS activity under fasted conditions. Additionally, aged PASK-deficient mice recorded an overexpression of the longevity gene FoxO3a, and maintained elevated PCNA protein, suggesting that hepatic cell repair mechanisms might be functional. PASK-deficient mice have better insulin sensitivity and no glucose intolerance, as confirmed by a normal HOMA-IR index. PASK may be a good target for reducing damage during aging.