Aquatide Activation of SIRT1 Reduces Cellular Senescence through a SIRT1-FOXO1-Autophagy Axis

A literature review on signaling pathways of cervical cancer cell death-apoptosis induced by Traditional Chinese Medicine

ETHNOPHARMACOLOGICAL RELEVANCE

Cervical cancer (CC) is a potentially lethal disorder that can have serious consequences for a woman's health. Because early symptoms are typically only present in the middle to late stages of the disease, clinical diagnosis and treatment can be challenging. Traditional Chinese medicine (TCM) has been shown to have unique benefits in terms of alleviating cancer clinical symptoms, lowering the risk of recurrence after surgery, and reducing toxic side effects and medication resistance after radiation therapy. It has also been shown to improve the quality of life for patients. Because of its improved anti-tumor effectiveness and biosafety, it could be considered an alternative therapy option. This study examines how TCM causes apoptosis in CC cells via signal transduction, including the active components and medicinal tonics. It also intends to provide a reliable clinical basis and protocol selection for the TCM therapy of CC.

METHODS

The following search terms were employed in PubMed, Web of Science, Embase, CNKI, Wanfang, VIP, SinoMed, and other scientific databases to retrieve pertinent literature on "cervical cancer," "apoptosis," "signaling pathway," "traditional Chinese medicine," "herbal monomers," "herbal components," "herbal extracts," and "herbal formulas."

RESULTS

It has been demonstrated that herbal medicines can induce apoptosis in cells of the cervix, a type of cancer, by influencing the signaling pathways involved.

CONCLUSION

A comprehensive literature search was conducted, and 148 papers from the period between January 2017 and December 2023 were identified as eligible for inclusion. After a meticulous process of screening, elimination and summary, generalization, and analysis, it was found that TCM can regulate multiple intracellular signaling pathways and related molecular targets, such as STAT3, PI3K/AKT, Wnt/β-catenin, MAPK, NF-κB, p53, HIF-1α, Fas/FasL and so forth. This regulatory capacity was observed to induce apoptosis in cervical cancer cells. The study of the mechanism of TCM against cervical cancer and the screening of new drug targets is of great significance for future research in this field. The results of this study will provide ideas and references for the future development of Chinese medicine in the diagnosis and treatment of cervical cancer.

PARP-2 mediates cardiomyocyte aging and damage induced by doxorubicin through SIRT1 Inhibition

Doxorubicin (DOX) is an anthracycline antibiotic used as an antitumor treatment. However, its clinical application is limited due to severe side effects such as cardiotoxicity. In recent years, numerous studies have demonstrated that cellular aging has become a therapeutic target for DOX-induced cardiomyopathy. However, the underlying mechanism and specific molecular targets of DOX-induced cardiomyocyte aging remain unclear. Poly (ADP-ribose) polymerase (PARP) is a family of protein post-translational modification enzymes in eukaryotic cells, including 18 members. PARP-1, the most well-studied member of this family, has become a potential molecular target for the prevention and treatment of various cardiovascular diseases, such as DOX cardiomyopathy and heart failure. PARP-1 and PARP-2 share 69% homology in the catalytic regions. However, they do not entirely overlap in function. The role of PARP-2 in cardiovascular diseases, especially in DOX-induced cardiomyocyte aging, is less studied. In this study, we found for the first time that down-regulation of PARP-2 can inhibit DOX-induced cellular aging in cardiomyocytes. On the contrary, overexpression of PARP-2 can aggravate DOX-induced cardiomyocyte aging and injury. Further research showed that PARP-2 inhibited the expression and activity of SIRT1, which in turn was involved in the development of DOX-induced cardiomyocyte aging and injury. Our findings provide a preliminary experimental basis for establishing PARP-2 as a new target for preventing and treating DOX cardiomyopathy and related drug development.

A comprehensive AI-driven analysis of large-scale omic datasets reveals novel dual-purpose targets for the treatment of cancer and aging

As aging and tumorigenesis are tightly interconnected biological processes, targeting their common underlying driving pathways may induce dual-purpose anti-aging and anti-cancer effects. Our transcriptomic analyses of 16,740 healthy samples demonstrated tissue-specific age-associated gene expression, with most tumor suppressor genes downregulated during aging. Furthermore, a large-scale pan-cancer analysis of 11 solid tumor types (11,303 cases and 4431 control samples) revealed that many cellular processes, such as protein localization, DNA replication, DNA repair, cell cycle, and RNA metabolism, were upregulated in cancer but downregulated in healthy aging tissues, whereas pathways regulating cellular senescence were upregulated in both aging and cancer. Common cancer targets were identified by the AI-driven target discovery platform-PandaOmics. Age-associated cancer targets were selected and further classified into four groups based on their reported roles in lifespan. Among the 51 identified age-associated cancer targets with anti-aging experimental evidence, 22 were proposed as dual-purpose targets for anti-aging and anti-cancer treatment with the same therapeutic direction. Among age-associated cancer targets without known lifespan-regulating activity, 23 genes were selected based on predicted dual-purpose properties. Knockdown of histone demethylase KDM1A, one of these unexplored candidates, significantly extended lifespan in Caenorhabditis elegans. Given KDM1A's anti-cancer activities reported in both preclinical and clinical studies, our findings propose KDM1A as a promising dual-purpose target. This is the first study utilizing an innovative AI-driven approach to identify dual-purpose target candidates for anti-aging and anti-cancer treatment, supporting the value of AI-assisted target identification for drug discovery.

Long Non-coding RNA H19-Overexpressing Exosomes Ameliorate UVB-Induced Photoaging by Upregulating SIRT1 Via Sponging miR-138

UVB-induced photoaging is characterized by wrinkle formation, slackness and senile plaques, affecting the health and beauty of human being. Our previous study revealed that exosomes derived from adipose-derived stem cells (ADSCs) could efficiently alleviate UVB-induced photodamage. However, the functional ingredients in exosomes were undefined. LncRNA H19, one of the well-researched lncRNAs in exosomes, exhibits multiple physiological effects. This study aims to demonstrate the photo-protective role of lncRNA H19 on skin photoaging in UVB-irradiated human skin fibroblasts cells (HSFs) and Kunming mice. LncRNA H19-overexpressing exosomes (H19-Exo) were isolated from the supernatant of ADSCs infected with lncRNA H19-loaded lentivirus. The results showed that H19-Exo significantly inhibited MMPs production, DNA damage and ROS generation while enhancing procollagen type I synthesis in UVB-irradiated HSFs. Meanwhile, H19-Exo markedly reversed epidermal thickening and collagen degradation in UVB-irradiated mice. Furthermore, luciferase reporter assays indicated that lncRNA H19 acted as a sponge for miR-138 expression, and SIRT1 was targeted by miR-138. Evidence from both in vitro and in vivo studies also revealed that H19-Exo could enhance SIRT1 expression by knocking down miR-138. In conclusion, lncRNA H19 served as a therapeutic candidate in treating UVB-induced skin photoaging by upregulation of SIRT1 via miR-138.

Assessment of in vitro anti-skin aging activities of Phyllanthus indofischeri Bennet extracts for dermatological and aesthetic applications

Giant Indian Gooseberry (GIG) or Phyllanthus indofischeri Bennet are commercially cultivated and commonly used herbs in Traditional medicine, especially in Thailand. The aim of this study was to assess the potential of the GIG extracts in anti-aging activities to be a dermatological application. The juice, meat residues, and seeds of GIG collected from Sra Kaeo Province, Thailand, were extracted by the Boiling method (B) and the Maceration process (M) by using 95% ethanol as a solvent. The GIG extracts gave the total phenolic, total flavonoid contents and quercetin contents, as well as exhibited anti-oxidative activities. The GIG-R-B extract inhibited tyrosinase activity and had the highest anti-melanogenesis activity on B16F10 cells at 31.63 ± 0.70%. The GIG-S-B, GIG-S-M, and GIG-R-M extracts demonstrated the highest collagen biosynthesis, which was comparable to vitamin C (p < 0.05), whereas the GIG-R-B extracts gave the highest stimulation of anti-aging genes (SIRT1 and FOXO1). All extracts at the concentration of 0.1 mg/mL showed no cytotoxicity on human skin fibroblasts. Therefore, the GIG-S-B extract was discovered to be a promising natural anti-aging agent for dermatological health and aesthetic applications that can be further developed in cosmetic, functional food and food supplement industries.

c-Jun N-terminal kinase signaling in cellular senescence

Cellular senescence leads to decreased tissue regeneration and inflammation and is associated with diabetes, neurodegenerative diseases, and tumorigenesis. However, the mechanisms of cellular senescence are not fully understood. Emerging evidence has indicated that c-Jun N-terminal kinase (JNK) signaling is involved in the regulation of cellular senescence. JNK can downregulate hypoxia inducible factor-1α to accelerate hypoxia-induced neuronal cell senescence. The activation of JNK inhibits mTOR activity and triggers autophagy, which promotes cellular senescence. JNK can upregulate the expression of p53 and Bcl-2 and accelerates cancer cell senescence; however, this signaling also mediates the expression of amphiregulin and PD-LI to achieve cancer cell immune evasion and prevents their senescence. The activation of JNK further triggers forkhead box O expression and its target gene Jafrac1 to extend the lifespan of Drosophila. JNK can also upregulate the expression of DNA repair protein poly ADP-ribose polymerase 1 and heat shock protein to delay cellular senescence. This review discusses recent advances in understanding the function of JNK signaling in cellular senescence and includes a comprehensive analysis of the molecular mechanisms underlying JNK-mediated senescence evasion and oncogene-induced cellular senescence. We also summarize the research progress in anti-aging agents that target JNK signaling. This study will contribute to a better understanding of the molecular targets of cellular senescence and provides insights into anti-aging, which may be used to develop drugs for the treatment of aging-related diseases.

The role of sirtuins in dermal fibroblast function

The sirtuins are a family of seven proteins that perform a variety of dermatological functions and help maintain both the structure and function of the skin. More specifically, the sirtuins have been shown to be altered in multiple dermal cell types including dermal fibroblasts. The functions of dermal fibroblasts are extensive, and include playing a significant role in wound healing as well as helping to maintain the integrity of the skin. As dermal fibroblasts age, they can undergo a state of permanent cell cycle arrest, known as cellular senescence. This senescent process can occur as a result of various stressors, including oxidative stress, ultraviolet radiation -induced stress, and replicative stress. In recent years, there has been a growing interest in both enhancing the cutaneous fibroblast’s ability to facilitate wound healing and altering fibroblast cellular senescence. Thus, in this review, we examine the relationship between sirtuin signaling and dermal fibroblasts to understand how this family of proteins may modulate skin conditions ranging from the wound healing process to photocarcinogenesis associated with fibroblast senescence. Additionally, we offer supporting data from experiments examining the relationship between fibroblast senescence and sirtuin levels in an oxidative stress model indicating that senescent dermal fibroblasts exhibit diminished sirtuin levels. Furthermore, we survey the research on the role of sirtuins in specific dermatological disease states that where dermal fibroblast function has been implicated. Finally, we conclude with outlining potential clinical applications of sirtuins in dermatology. In sum, we find that the literature on the involvement of sirtuins in dermal fibroblasts is limited, with research still in its early stages. Nevertheless, intriguing preliminary findings merit additional investigation into the clinical implications of sirtuins in dermatology.

Naringin protects mice from D-galactose-induced lung aging and mitochondrial dysfunction: Implication of SIRT1 pathways

AIM

Aging is the leading risk factor for diminishing lung function, as well as injury and lung disorder. The target of our research was to examine the potential protective effect of naringin and the possible role of SIRT1 in mice with D-galactose-induced lung aging, by evaluating its effects on antioxidant systems, mitochondrial biogenesis, autophagy, and apoptosis, by referring to the potential involvement of Nrf2/NQO1, LKB1/AMPK/PGC-1α, FOXO1, and P53/caspase-3 signaling.

MATERIAL AND METHODS

The mice were randomly sorted into 5 groups (10 each): 1st^: normal group received subcutaneous normal saline and intragastric distilled water, 2nd^: naringin 300 mg/kg orally, 3rd^: D-galactose (200 mg/kg/day) was administered subcutaneously into mice for eight weeks, to accelerate aging, 4th & 5th: oral naringin (150, 300 mg/kg) was given daily concurrently with D-galactose injection for 8 weeks.

KEY FINDING

In silico investigation revealed that naringin substantially stimulates the SIRT1 and AMPK molecules. At the molecular level, our findings indicated that treatment with naringin stimulated the mitochondrial biogenesis pathway through regulation of the LKB1/AMPK/PGC-1α signals and upregulated FOXO1-mediated autophagy. Furthermore, naringin exhibited antioxidant properties by activating the Nrf2/NQO1 pathway and inhibiting MDA and AGEs levels. In addition, Naringin ameliorated alveolar spaces destruction and bronchial wall thickening, as well as alleviated P53/caspase-3 apoptosis signaling.

SIGNIFICANCE

Naringin exerts protective effects against D-galactose-induced lung aging and enhances longevity by activating SIRT1. SIRT1 regulates various aging-related molecular pathways via restoring pro-oxidant/antioxidant homeostasis, activation of mitochondrial biogenesis, modulating of autophagy and inhibition of apoptosis.

Induction of autophagy improves skin and hair conditions in dogs with underlying diseases

Background

Autophagy was reported to play a crucial role in maintaining general and skin health.

Methods

The study used a synthesized autophagy inducer (AI) (Aquatide™ cospharm Inc.; Daejeon, Korea), for evaluating the effects of autophagy on skin and hair in dogs. Twenty-two dogs with poor skin and hair which were diagnosed with canine atopic dermatitis (CAD) or pituitary-dependent hyperadrenocorticism (PDH) were included. Clinical scores using Canine Atopic Dermatitis Extent and Severity Index-04 (CADESI-04), Pruritus Visual Analog Scale (PVAS) and skin barrier function using measurement of transepidermal water loss (TEWL) were evaluated and canine keratinocytes were also used in vitro investigation of pro-inflammatory cytokines after AI treatment.

Results

In the AI group, clinical scores and skin barrier function were improved at week 8 significantly compared to in the other groups. In particular, the AI significantly improved the hair surface damage at 8 weeks compared to the baseline. In vitro, the AI reduced pro-inflammatory cytokines by activating the 78-kDa glucose-regulated protein (GRP78).

Conclusion

AI improve skin barrier function and hair damage and reduce pro-inflammatory cytokines by inhibiting reactive oxygen species (ROS) production in dogs.

Salidroside Ameliorates Ultraviolet-Induced Keratinocyte Injury by Inducing SIRT1-Dependent Autophagy

Introduction

Methods

Results

Discussion

Metabolic Regulation: A Potential Strategy for Rescuing Stem Cell Senescence

Stem cell senescence and exhaustion are closely related to organ failure and individual aging, which not only induces age-related diseases, but also hinders stem cell applications in regenerative medicine. Thus, it's imminent to find effective ways to delay and retrieve stem cell senescence. Metabolic abnormalities are one of the main characteristics of age-associated declines in stem cell function. Understanding the underlying mechanisms may reveal potential strategies for ameliorating age-associated phenotypes and treating age-related diseases. This review focuses on recent advances in the association between metabolism including glucose, lipid, glutamine and NAD⁺ metabolism and stem cell senescence, as well as the other properties like proliferation and differentiation. Layers of studies are summarized to demonstrate how metabolism varies in senescent stem cells and how metabolic reprogramming regulates stem cell senescence. Additionally, we mentioned some recent progress in therapeutic strategies to rejuvenate dysfunctional aged stem cells. Finally, a brief conclusion about the prospect of metabolic regulation as a potential strategy for rescuing stem cell senescence is displayed. Stem cell senescence is induced by the metabolic reprogramming. The metabolic alterations of glucose, lipid, glutamine and NAD⁺ can conversely facilitate or inhibit stem cell senescence. Glycolysis, OXPHOS and PPP are all attenuated. But gluconeogenesis alterations still remain unclear. In lipid metabolisms, both FAO and DNL are suppressed. As for the glutamine metabolism, stem cells' dependence on glutamine is enhanced. Last, NAD⁺ metabolism undergoes a down-regulated synthesis and up-regulated consumption. All these alterations can be potential targets for reversing stem cell senescence.

NAD+ improved experimental autoimmune encephalomyelitis by regulating SIRT1 to inhibit PI3K/Akt/mTOR signaling pathway

OBJECTIVE

To investigate the effect of NAD+ on thymus autophagy in experimental autoimmune encephalomyelitis (EAE) mice through SIRT1.

METHODS

Bioinformatic analysis was used to identify hub genes. Forty female C57BL/6 mice were randomly divided into 4 groups: control, EAE, NAD+, and NAD+ +SIRT1 inhibitor (SIRT-IN-3) groups and SIRT1 group. The NAD+ group and SIRT1 inhibitor group were treated with NAD+ drug and fed for 4 weeks. The neurological function scores were evaluated weekly. The thymus tissues of wild-type mice were removed, ground and filtered into single-cell suspension. MOG 35-55 (1 μg/mL) was given to primary thymic epithelial cells (TECs) to induce EAE model in vitro. The expression of LC-3A/B was observed by immunofluorescence. The expressions or the activation/phosphorylation of associated proteins were detected by Western blot.

RESULTS

Enrichment analysis showed PI3K-Akt-mTOR and autophagy pathway were main terms in EAE diseases, and the relationship between NAD+ and SIRT1. The activation of p-PI3K, p-Akt and p-mTOR were the highest in the EAE group consistent with decreased P62, Beclin1, LC-3A/B and SIRT1, and NAD+ reversed these results, furthermore SIRT1 inhibitor: SIRT-IN3 weakened the NAD+' effects in both in vivo and in vitro experiments. Immunofluorescence study in vivo and in vitro were accord with the results of western blot.

CONCLUSIONS

NAD+ exerted a protective effect on EAE mice by inhibiting PI3K/Akt/mTOR signaling pathway through SIRT1 in TECs, and prevented EAE mice from sustained damage.

β-Nicotinamide Mononucleotide (NMN) Administrated by Intraperitoneal Injection Mediates Protection Against UVB-Induced Skin Damage in Mice

Objective

Ultraviolet light is an important environmental factor that induces skin oxidation, inflammation, and other diseases. Nicotinamide mononucleotide (NMN) has the effect of anti-oxidation and improving various physiological processes. This study explores the protective effect of NMN monomers given via intraperitoneal injection on UVB-induced photodamage.

Methods

We used a murine model of UVB-induced photodamage to evaluate the effect of an NMN monomer on photoaging skin by assessing skin and liver tissue sections, serum and skin oxidative stress levels, inflammatory markers, mRNA expression, and protein expression of skin- and liver-related genes.

Results

The results showed that NMN treatment blocked UVB-induced photodamage in mice, maintaining normal structure and amount of collagen fibers, normal thickness of epidermis and dermis, reducing the production of mast cells, and maintaining complete organized skin structure. NMN intraperitoneal injection also maintained the normal morphology of the mouse liver after UVB exposure. Meanwhile, NMN intraperitoneal injection was found to increase antioxidant ability and regulate the proinflammatory response of the skin and liver to UVB irradiation by enhancing the activity of antioxidant enzymes, release of anti-inflammatory cytokines, reduction of hydrogen peroxide production (H₂O₂), and decreased inflammatory cytokines. Furthermore, RT-qPCR results indicated that NMN reduced oxidative stress of skin and liver by promoting the activation of the AMP-activated protein kinase (AMPK) signaling pathway and further increasing the expression of downstream antioxidant genes of AMPK. RT-qPCR results also revealed that NMN treatment could downregulate the mRNA expression of interleukin (IL)-6, interleukin (IL)-1β, and tumor necrosis factor (TNF)-α, and upregulate NF-kappa-B inhibitor-α (IκB-α) and interleukin (IL)-10 by inhibiting the activation of nuclear factor-κBp65 (NFκB-p65). Finally, NMN upregulated AMPK, IκB-α, SOD1, and CAT in the skin and downregulated NF-κBp65 protein expression, which is in line with the RT-qPCR results.

Conclusion

Based on the above results, NMN monomer treatment with intraperitoneal injection also block the photodamage caused by UVB irradiation in mice by regulating the oxidative stress response and inflammatory response.

Salvianolic Acid C Protects against Cisplatin-Induced Acute Kidney Injury through Attenuation of Inflammation, Oxidative Stress and Apoptotic Effects and Activation of the CaMKK-AMPK-Sirt1-Associated Signaling Pathway in Mouse Models

Acute kidney injury (AKI) is a sudden reduction in kidney activity and has a high mortality rate. Salvianolic acid C (SAC), one of the main polyphenolic components of Salvia miltiorrhiza, displays significant pharmacologically active effects. An animal model of cisplatin-induced kidney injury was used to study the potential of SAC to improve AKI. First, SAC was administered intraperitoneally in mice for 10 consecutive days, and then cisplatin was administered intraperitoneally on day 7 to establish a nephrotoxicity mouse model. SAC mitigated renal histological changes, blood creatinine (CRE) and blood urea nitrogen (BUN) production and the levels of inflammatory mediators in the cisplatin-induced AKI. Furthermore, malondialdehyde (MDA) levels were reduced and glutathione (GSH) was increased after intraperitoneal injection (i.p.) administration of SAC. In addition, based on Western blot data, SAC reduced the expression of inducible NO synthase (iNOS), cyclooxygenase-2 (COX-2), nuclear factor kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) activation in mouse renal tissues. Finally, SAC diminished the level of TLR-4 expression and enhanced the production of several antioxidative enzymes (superoxidase dismutase (SOD1), glutathione peroxidase (GPx3), catalase, nuclear-factor-erythroid-2-related factor 2 (Nrf2) and heme oxygenase 1 (HO-1)), Sirtuin 1 (Sirt1), p-AMP-activated protein kinase (AMPK) and p-Ca²⁺/calmodulin-dependent protein kinase kinase (CaMKK). In addition, Sirt1 inhibition (EX 527) inverted the effect of SAC against cisplatin-induced nephrotoxicity. Collectively, SAC provides a therapeutic target with promising clinical potential after cisplatin treatment by attenuating oxidative stress and inflammation.

The osteogenic differentiation of human bone marrow stromal cells induced by nanofiber scaffolds using bioinformatics

This article aims to investigate the mechanism of behaviors of human bone marrow stromal cells (hBMSCs) affected by scaffold structure combining Monte Carlo feature selection (MFCS), incremental feature selection (IFS) and support vector machine (SVM). The specific differentially expressed genes (DEGs) of hBMSCs cultured on nanofiber (NF) scaffolds and freeform fabrication (FFF) scaffolds were obtained. Key genes were screened from common genes between osteogenic DEGs and NF specific DEGs with MFCS, IFS and SVM. The results demonstrated that NF scaffolds induced hBMSCs to express more genes related to osteogenic differentiation. Finally, 16 key genes were identified among the common genes. The common genes were significantly enriched in Rap1 signaling pathway, extracellular matrix and ossification. The results in this study suggested that the gene expression of hBMSCs was sensitive to NF scaffolds and FFF scaffolds, and the osteogenic differentiation of hBMSCs could be enhanced by NF scaffolds.

SIRT1: Mechanism and Protective Effect in Diabetic Nephropathy

Diabetic nephropathy (DN) is referred to as the microvascular complication of the kidneys induced by insufficient production of insulin or an ineffective cellular response to insulin, and is the main cause of end-stage renal disease. Currently, available therapies provide only symptomatic relief and fail to improve the outcome of diabetic nephropathy. Studies on diabetic animals had shown overexpression of SIRT1 in both podocytes and renal tubular cells attenuated proteinuria and kidney injury in the animal model of DN. Sirt1 exerts renoprotective effects in DKD in part through the deacetylation of transcription factors involved in the disease pathogenesis, such as NF-кB, Smad3, FOXO and p53. The purpose of this review is to highlight the protective mechanism of SIRT1 involved in the pathogenesis of diabetic nephropathy.

Hypoxic postconditioning-induced neuroprotection increases neuronal autophagy via activation of the SIRT1/FoxO1 signaling pathway in rats with global cerebral ischemia

Hypoxic postconditioning (HPC) has been reported to be a beneficial and promising treatment for global cerebral ischemia (GCI). However, its neuroprotective mechanism remains unclear. The aim of the present study was to determine whether the protective effects of HPC in a rat model of GCI were due to the upregulation of autophagy via the silent information regulator transcript-1 (SIRT1)/Forkhead box protein 1 (FoxO1) pathway. Morris water maze test revealed that HPC attenuated cognitive damage in GCI rats. HPC also significantly increased the levels of the autophagy-related protein LC3-II, SIRT1 and FoxO1 compared with those in the GCI group. However, the HPC-induced LC3-II upregulation was blocked by the SIRT1 inhibitor EX527. These results suggested that the beneficial effects of HPC on GCI rats were due to the upregulation of ischemiainduced autophagy and involved the SIRT1/FoxO1 signaling pathway.

The Role of Autophagy in Skin Fibroblasts, Keratinocytes, Melanocytes, and Epidermal Stem Cells

Human skin acts as a barrier to protect our bodies from UV rays and external pathogens and to prevent water loss. Phenotypes of aging, or natural aging due to chronic damage, include wrinkles and the reduction of skin thickness that occur because of a loss of skin cell function. The dysregulation of autophagy, a lysosome-related degradation pathway, can lead to cell senescence, cancer, and various human diseases due to abnormal cellular homeostasis. Here, we discuss the roles and molecular mechanisms of autophagy involved in the anti-aging effects of autophagy and the relationship between autophagy and aging in skin cells.

Gypenoside inhibits ox-LDL uptake and foam cell formation through enhancing Sirt1-FOXO1 mediated autophagy flux restoration

BACKGROUND

Gypenoside (GP) is the major bioactive constituent of G. pentaphyllum, a traditional Chinese medicine. It has been reported that GP can affect autophagy and lipid metabolism in cultured cells. We hypothesize that GP can inhibit foam cell formation in cultured macrophages through autophagy modulation.

METHODS

THP1 cells were cultured and treated with oxidized low-density lipoprotein (ox-LDL), followed by GP treatment at different concentrations. The autophagy flux was evaluated using western blot and confocal microscope analyses. The ox-LDL uptake and foam cell formation abilities were measured.

RESULTS

We found that ox-LDL impaired the autophagy flux in the cultured macrophages, indicated by a significant reduction of LC3-II and autophagosome puncta quantification, as well as an accumulation of p62 proteins. GP treatment, however, dose-dependently restored the autophagy flux impaired by ox-LDL and reduced the ox-LDL uptake and foam cell transformation from THP1 cells, which can be alleviated, or exacerbated, by modulation of autophagy status using autophagy enhancer or inhibitor. Coimmunoprecipitation assays showed that GP up-regulated Srit1 and FOXO1 expression and enhanced their direct interaction, and thus contributed to the regulation of autophagy.

CONCLUSION

GP inhibits ox-LDL uptake and foam cell formation through enhancing Sirt1-FOXO1 mediated autophagy flux restoration, suggesting this compound has therapeutic potential for atherosclerosis.

SIRT1 Activation Using CRISPR/dCas9 Promotes Regeneration of Human Corneal Endothelial Cells through Inhibiting Senescence

Human corneal endothelial cells (hCECs) are restricted in proliferative capacity in vivo. Reduction in the number of hCEC leads to persistent corneal edema requiring corneal transplantation. This study demonstrates the functions of SIRT1 in hCECs and its potential for corneal endothelial regeneration. Cell morphology, cell growth rates and proliferation-associated proteins were compared in normal and senescent hCECs. SIRT1 was activated using the CRISPR/dCas9 activation system (SIRT1a). The plasmids were transfected into CECs of six-week-old Sprague–Dawley rats using electroporation and cryoinjury was performed. Senescent cells were larger, elongated and showed lower proliferation rates and lower SIRT1 levels. SIRT1 activation promoted the wound healing of CECs. In vivo transfection of SIRT1a promoted the regeneration of CECs. The proportion of the S-phase cells was lower in senescent cells and elevated upon SIRT1a activation. SIRT1 regulated cell proliferation, proliferation-associated proteins, mitochondrial membrane potential, and oxidative stress levels. In conclusion, corneal endothelial senescence is related with a decreased SIRT1 level. SIRT1a promotes the regeneration of CECs by inhibiting cytokine-induced cell death and senescence. Gene function activation therapy using SIRT1a may serve as a novel treatment strategy for hCEC diseases.

Topical application of autophagy-activating peptide improved skin barrier function and reduced acne symptoms in acne-prone skin

BACKGROUND

Recent studies about the important roles of autophagy signaling in sebaceous lipogenesis and epidermal differentiation suggest potential benefits of autophagy activation in acne.

AIMS

To investigate the effects of an autophagy activator on acne-prone skin.

METHODS

Autophagy signaling in human immortalized SZ95 sebocytes, normal human epidermal keratinocytes, and 3D reconstituted skin was examined. Effects of an autophagy-activating peptide on sebaceous lipogenesis were measured by fluorescence microscopic analysis. The clinical efficacy in acne-prone skin was evaluated through an eight-week, double-blind, randomized, vehicle-controlled study. Changes in skin surface lipid compositions were further analyzed.

RESULTS

In cultured sebocytes and keratinocytes, the investigated autophagy-activating peptide increased LC3-II expression, indicating a stimulation of autophagy signaling. Testosterone and linoleic acid treatment induced lipogenesis in cultured sebocytes and is further inhibited by the autophagy activator peptide treatment. Increased expression of differentiation marker proteins in cultured keratinocytes was also observed by autophagy-activating peptide. In clinical study, reduction of closed comedones and the amount of skin surface lipids as well as of trans-epidermal water loss (TEWL) were observed in acne-prone skin after autophagy-activating peptide application. In addition, reduction of squalene and increase in cholesterol were observed after an 8-week application.

CONCLUSIONS

Topical application of an autophagy activator downregulated sebaceous lipogenesis and improved the skin barrier function. Considering the important roles of sebum and skin barrier function in acne pathogenesis, autophagy activation might represent a new therapeutic option in early forms of acne.

SIRT1 and aging related signaling pathways

Aging is a biological phenomenon in which the structure and function of organisms declining with the increasing of age. It has become a major risk factor of human diseases, including diabetes, cancers, cardiovascular diseases and neurodegenerative diseases. Silencing information regulator 2 related enzyme 1(sirtuin1, SIRT1) is an NAD⁺-dependent deacetylase, which has been reported to be involved in the regulation of cellular senescence and aging. The expression of SIRT1 is diminished with aging in mice. By contrast, increased expression of SIRT1 is sufficient to extend lifespan in yeast, caenorhabditis elegans and mice. In this review, the relationship between SIRT1 and aging and various signaling networks associated with aging, including NF-κB, AMPK, mTOR, P53, PGC1α, and FoxOs will be discussed. Meanwhile, the potential therapeutic strategies of targeting SIRT1 to anti-aging are also addressed.

Overexpression of Pitx1 attenuates the senescence of chondrocytes from osteoarthritis degeneration cartilage-A self-controlled model for studying the etiology and treatment of osteoarthritis

To explore the role of low expression of Pitx1 in degenerative cartilage tissue. A cartilage injury model was established by using the cartilage scratch method. The newly generated tissue by BrdU labeled in injured cartilage region expressed SOX-9 and Col2A1 in 5-week-old rats. Compared with that, the number of BrdU-positive cells was lower in 4-month-old cartilage injury model rats. Compared with that in lateral cartilage, the expression of Pitx1 was lower in medial cartilage. Compared with chondrocytes derived from the lateral cartilage, chondrocytes derived from the medial cartilage exhibited significantly increased cell aging, as determined by SA-β-GAL staining; downregulated Pitx1 expression; reduced autophagy levels; and decreased Col2A1 expression in a chondrogenic differentiation assay. Inhibition of Pitx1 expression in chondrocytes from the lateral cartilage significantly increased the ratio of cell senescence. Overexpression of Pitx1 in chondrocytes derived from the medial cartilage decreased the cell senescence ratio. In a luciferase assay, Pitx1 was found to promote Sirt1 gene transcription. Decreased Pitx1 expression is an essential cause of cartilage degeneration in the medial tibial plateau. The described self-controlled model is an excellent way to study OA etiology and screen therapeutic drugs for OA.

Autophagy induction can regulate skin pigmentation by causing melanosome degradation in keratinocytes and melanocytes

Autophagy regulates cellular turnover by disassembling unnecessary or dysfunctional constituents. Recent studies demonstrated that autophagy and its regulators play a wide variety of roles in melanocyte biology. Activation of autophagy is known to induce melanogenesis and regulate melanosome biogenesis in melanocytes. Also, autophagy induction was reported to regulate physiologic skin color via melanosome degradation, although the downstream effectors are not yet clarified. To determine the role of autophagy as a melanosome degradation machinery, we administered several autophagy inducers in human keratinocytes and melanocytes. Our results showed that the synthetic autophagy inducer PTPD-12 stimulated autophagic flux in human melanocytes and in keratinocytes containing transferred melanosomes. Increased autophagic flux led to melanosome degradation without affecting the expression of MITF. Furthermore, the color of cell pellets of both melanocytes and keratinocytes was visibly lightened. Inhibition of autophagic flux by chloroquine resulted in marked attenuation of PTPD-12-induced melanosome degradation, whereas the expression of melanogenesis pathway genes and proteins remained unaffected. Taken together, our results suggest that the modulation of autophagy can contribute to the regulation of melanocyte biology and skin pigmentation.

Metformin inhibits high glucose-induced mesangial cell proliferation, inflammation and ECM expression through the SIRT1-FOXO1-autophagy axis

The aim of this study was to investigate the role of metformin in high glucose-induced mesangial cell proliferation, inflammation and extracellular matrix (ECM) accumulation and to elucidate the underlying mechanism of metformin function. An MTT assay was used to examine rat mesangial cell (RMC) proliferation. The levels of TNF-α, IL-6 and TGF-β in RMCs were determined by ELISA. The protein expression of fibronectin, collagen IV and autophagy-related proteins (Beclin-1, LC3-I and LC3-II) in RMCs was detected using western blot. Fluorescence microscopy analysis was carried out to evaluate RMC autophagy. Our results showed that high glucose-induced RMC proliferation, inflammation and ECM expression, but these effects were markedly reduced by metformin. We confirmed that metformin suppressed high glucose-induced RMC proliferation, inflammation and ECM expression via induction of autophagy. Mechanistic investigation demonstrated an axis of SIRT1-FOXO1 in RMC autophagy. Our data indicated that metformin inhibits high glucose-induced mesangial cell proliferation, inflammation and ECM expression through a SIRT1-FOXO1-autophagy axis.

Salidroside protects against ox-LDL-induced endothelial injury by enhancing autophagy mediated by SIRT1-FoxO1 pathway

Background

Atherosclerosis is a condition with the vascular accumulation of lipid plaques, and its main major contributing factor is endothelial injury induced by oxidized low-density lipoprotein (ox-LDL). Salidroside (SAL) is the primary active ingredient of Rhodiola rosea, and exhibits antioxidant properties on endothelial cells and alleviates atherosclerosis. However, the effect of SAL on autophagy in ox-LDL-induced vascular endothelial injury remains unclear. Here, we investigated the effect and underlying mechanisms of SAL on autophagy in human umbilical vein endothelial cells (HUVECs).

Methods

HUVECs were incubated with ox-LDL to induce in vitro atherosclerosis model. The cell viability and injury were evaluated by cell counting kit-8 (CCK-8) assay and lactate dehydrogenase (LDH) release assay. The oxidative stress was evaluated by NADPH oxidase, malondialdehyde (MDA) and superoxide dismutase (SOD) activities. Immunofluorescence was performed to detect autophagy using LC3β antibody. Quantitative real-time PCR (qRT-PCR) and western blot were performed to measure the mRNA expressions of SIRT1 and Forkhead box O1 (FOXO1). Nicotinamide (NAM) and AS1842856 were used to inhibit activities of SIRT1 and FOXO1, respectively.

Results

Exposure of HUVECs to ox-LDL (100 μg/mL) reduced cell viability, increased cellular MDA, and reduced SOD in a concentration-dependent manner. The pretreatment with SAL (20, 50 and 100 μM) significantly enhanced the cell viability and decreased LDH release in HUVECs exposed to ox-LDL (100 μg/mL). ox-LDL induced autophagy in HUVECs, which was further enhanced by pretreatment with SAL. However, SAL attenuated increase in oxidative stress in HUVECs induced by ox-LDL. ox-LDL reduced mRNA and protein expressions of SIRT1 and FOXO1, which could be reversed by SAL. The protective, anti-oxidative and pro-autophagic effects of SAL could be obviously abolished by cotreatment with SIRT1 inhibitor or FOXO1 inhibitor.

Conclusion

Salidroside shows protective effect on endothelial cell induced by ox-LDL, and the mechanisms might be related to autophagy induction via increasing SIRT1 and FoxO1 expressions.

Chromatin remodeling factor BAZ1A regulates cellular senescence in both cancer and normal cells

AIMS

Cellular senescence is a well-known cancer prevention mechanism, inducing cancer cells to senescence can enhance cancer immunotherapy. However, how cellular senescence is regulated is not fully understood. Dynamic chromatin changes have been discovered during cellular senescence, while the causality remains elusive. BAZ1A, a gene coding the accessory subunit of ATP-dependent chromatin remodeling complex, showed decreased expression in multiple cellular senescence models. We aim to investigate the functional role of BAZ1A in regulating senescence in cancer and normal cells.

MATERIALS AND METHODS

Knockdown of BAZ1A was performed via lentivirus mediated short hairpin RNA (shRNA) in various cancer cell lines (A549 and U2OS) and normal cells (HUVEC, NIH3T3 and MEF). A series of senescence-associated phenotypes were quantified by CCK-8 assay, SA-β-Gal staining and EdU incorporation assay, etc. KEY FINDINGS: Knockdown (KD) of BAZ1A induced series of senescence-associated phenotypes in both cancer and normal cells. BAZ1A-KD caused the upregulated expression of SMAD3, which in turn activated the transcription of p21 coding gene CDKN1A and resulted in senescence-associated phenotypes in human cancer cells (A549 and U2OS).

SIGNIFICANCE

Our results revealed chromatin remodeling modulator BAZ1A acting as a novel regulator of cellular senescence in both normal and cancer cells, indicating a new target for potential cancer treatment.

Insights into autophagy machinery in cells related to skin diseases and strategies for therapeutic modulation

Autophagy, literally meaning "self-eating," is a highly conserved process that is part of the eukaryotic cell cycle. Morphologically, the double membrane contains vesicles with phagocytic components known as autophagosomes. Autophagy is often used as a cellular stress response and quality control mechanisms are used to maintain cell survival. Survival is facilitated by providing energy and metabolic precursors as well as removing damaged proteins or organelles. Moreover, autophagy refers to organelles fused together with part of the cell cytoplasm with a double or multi-membrane structure called phagosome. Research has demonstrated that autophagy is an important mediator of cell fate and has effects on inflammation, pathogen clearance, and antigen presentation. In recent years, studies discussing autophagy have increased in number. Nevertheless, only a small amount of research has considered the impact of autophagy on the pathogenesis of skin diseases. The skin is the largest organ of the body, with a surface area of around two square metre; it is the first line of defense against numerous environmental insults, including ultraviolet radiation, pathogens, mechanical stresses, and toxic chemicals. Autophagy is thought to be a vital modality for endogenous defenses against environmental derangements. This review provides an overview of autophagy machinery in keratinocytes, skin fibroblasts, melanocytes related to skin diseases as well as strategies for therapeutic modulation, for the future development of treatment for skin diseases.

Autophagy Activation by Crepidiastrum Denticulatum Extract Attenuates Environmental Pollutant-Induced Damage in Dermal Fibroblasts

Pollution-induced skin damage results in oxidative stress; cellular toxicity; inflammation; and, ultimately, premature skin aging. Previous studies suggest that the activation of autophagy can protect oxidation-induced cellular damage and aging-like changes in skin. In order to develop new anti-pollution ingredients, this study screened various kinds of natural extracts to measure their autophagy activation efficacy in cultured dermal fibroblast. The stimulation of autophagy flux by the selected extracts was further confirmed both by the expression of proteins associated with the autophagy signals and by electron microscope. Crepidiastrum denticulatum (CD) extract treated cells showed the highest autophagic vacuole formation in the non-cytotoxic range. The phosphorylation of adenosine monophosphate kinase (AMPK), but not the inhibition of mammalian target of rapamycin (mTOR), was observed by CD-extract treatment. Its anti-pollution effects were further evaluated with model compounds, benzo[a]pyrene (BaP) and cadmium chloride (CdCl₂), and a CD extract treatment resulted in both the protection of cytotoxicity and a reduction of proinflammatory cytokines. These results suggest that the autophagy activators can be a new protection regimen for anti-pollution. Therefore, CD extract can be used for anti-inflammatory and anti-pollution cosmetic ingredients.

The effect of autophagy-enhancing peptide in moisturizer on atopic dermatitis: a randomized controlled trial

Background: Pentasodium tetracarboxymethyl palmitoyl dipeptide-12 (PTPD-12), a newly-synthesized peptide, enhances the autophagy activity, ultimately managing inflammation. Objective: To determine the effect of a new moisturizer containing PTPD-12 as the treatment of mild-to-moderate atopic dermatitis (AD). Methods: In this double-blind, randomized, placebo-controlled trial, 43 patients with mild-to-moderate AD were randomly assigned to either the PTPD-12 or control groups. Evaluations were performed at baseline, week 2, and week 4, including SCORing Atopic Dermatitis (SCORAD) index score, corneometry, trans-epidermal water loss (TEWL), visual analog scale (VAS) for pruritus, 7-point investigator's global assessment (IGA), and collection of adverse events. Results: The PTPD-12 group showed significant improvement with respect to SCORAD score, skin hydration, TEWL, and pruritus at weeks 2 and 4 when compared with baseline. Although the control group showed significant improvement regarding the SCORAD score and skin hydration, no significant change in TEWL or pruritus was demonstrated throughout the study. The mean changes in the SCORAD index score, skin hydration, TEWL, pruritus, and number of patients with improvement in IGA were not statistically different between the two groups. Conclusion: The moisturizer with autophagy-stimulating property provides a good therapeutic option to mild-to-moderate atopic dermatitis by contributing to skin barrier restoration and control of inflammation.

MALAT1 lncRNA Induces Autophagy and Protects Brain Microvascular Endothelial Cells Against Oxygen-Glucose Deprivation by Binding to miR-200c-3p and Upregulating SIRT1 Expression

There is growing evidence that long noncoding RNAs (lncRNAs) play important roles in various biological processes. Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is one of the most highly upregulated lncRNAs in cerebral ischemia. However, the molecular mechanism of MALAT1 during cerebral ischemia is still unclear. This experiment is intended to investigate the role of MALAT1 in cerebral ischemia and its relationship with autophagy. Oxygen-glucose deprivation (OGD) in brain microvascular endothelial cells (BMECs) was used to mimic ischemic-like conditions in vitro. Real-time PCR, MTT, LDH assay and western blot were used to evaluate the levels of MALAT1, miR-200c-3p, SIRT1, cell survival and proteins. We found that the expression of MALAT1 and LC3BII were upregulated and p62 was downregulated by OGD. Inhibition of MALAT1 attenuated the autophagy activation and promoted cell death. We further revealed that MALAT1 downregulated the expression of miR-200c-3p by directly binding to miR-200c-3p. Furthermore, miR-200c-3p inhibited the autophagy and survival in BMECs by binding to 3'UTR of SIRT1, whereas MALAT1 overturned the inhibitory effect of miR-200c-3p. In conclusion, our study illuminated a novel Malat1-miR-200c-3p-SIRT1 pathway in the regulation of autophagy, in which, MALAT1 activates autophagy and promotes cell survival by binding to miR-200c-3p and upregulating SIRT1 expression.

Melatonin protects vertebral endplate chondrocytes against apoptosis and calcification via the Sirt1-autophagy pathway

Melatonin is reportedly associated with intervertebral disc degeneration (IDD). Endplate cartilage is vitally important to intervertebral discs in physiological and pathological conditions. However, the effects and mechanism of melatonin on endplate chondrocytes (EPCs) are still unclear. Herein, we studied the effects of melatonin on EPC apoptosis and calcification and elucidated the underlying mechanism. Our study revealed that melatonin treatment decreases the incidence of apoptosis and inhibits EPC calcification in a dose-dependent manner. We also found that melatonin upregulates Sirt1 expression and activity and promotes autophagy in EPCs. Autophagy inhibition by 3-methyladenine reversed the protective effect of melatonin on apoptosis and calcification, while the Sirt1 inhibitor EX-527 suppressed melatonin-induced autophagy and the protective effects of melatonin against apoptosis and calcification, indicating that the beneficial effects of melatonin in EPCs are mediated through the Sirt1-autophagy pathway. Furthermore, melatonin may ameliorate IDD in vivo in rats. Collectively, this study revealed that melatonin reduces EPC apoptosis and calcification and that the underlying mechanism may be related to Sirt1-autophagy pathway regulation, which may help us better understand the association between melatonin and IDD.

Role of the Inflammation-Autophagy-Senescence Integrative Network in Osteoarthritis

Osteoarthritis is the most common musculoskeletal disease causing chronic disability in adults. Studying cartilage aging, chondrocyte senescence, inflammation, and autophagy mechanisms have identified promising targets and pathways with clinical translatability potential. In this review, we highlight the most recent mechanistic and therapeutic preclinical models of aging with particular relevance in the context of articular cartilage and OA. Evidence supporting the role of metabolism, nuclear receptors and transcription factors, cell senescence, and circadian rhythms in the development of musculoskeletal system degeneration assure further translational efforts. This information might be useful not only to propose hypothesis and advanced models to study the molecular mechanisms underlying joint degeneration, but also to translate our knowledge into novel disease-modifying therapies for OA.

MiR-138-5p affects insulin resistance to regulate type 2 diabetes progression through inducing autophagy in HepG2 cells by regulating SIRT1

Insulin resistance (IR) is considered as a major factor of type 2 diabetes (T2D), which is seriously detrimental to human health. In our present study, we found that the expression of miR-138-5p was increased in the insulin-resistant HepG2 cells induced by TNF-α. Therefore, we hypothesized that miR-138-5p might play a regulatory role in the IR. To examine this hypothesis, HepG2 cells were transfected with miR-138-5p inhibitor. Silencing of miR-138-5p increased glucose uptake and glycogen synthesis of TNF-α-stimulated HepG2 cells and decreased glucose concentration in medium, suggesting that downregulation of miR-138-5p suppressed IR in HepG2 cells. Besides that, we found that sirtuin 1 (SIRT1) was the target gene of the miR-138-5p. Moreover, co-transfection with SIRT1-siRNA and miR-138-5p inhibitor suppressed glucose uptake and glycogen synthesis of HepG2 cells compared with miR-138-5p inhibitor-transfected group, indicating that downregulation of SIRT1 weakened the inhibitory effect of miR-138-5p inhibitor on IR. In addition, overexpressed SIRT1 increased Beclin1, LC3 II/I level, and the number of GFP-LC3 dots and decreased p62 level, whereas downregulation of SIRT1 had the opposite effects. Our results demonstrated that overexpressed SIRT1 activated autophagy in HepG2 cells. Moreover, we observed that 3-methyladenine (an inhibitor of autophagy) treatment decreased the high glucose uptake and glycogen synthesis of miR-138-5p inhibitor-transfected HepG2 cells, suggesting that the inhibition of autophagy abolished the inhibitory effect of miR-138-5p inhibitor on IR in HepG2 cells. Taken together, this study suggested that miR-138-5p contributed to the TNF-α-induced IR, possibly through inducing autophagy in HepG2 cells by regulating SIRT1. MiR-138-5p might be a potential and promising target for the treatment of IR.