PTEN Inhibition in Human Disease Therapy

HES1 is required for mouse fetal hematopoiesis

BACKGROUND

Hematopoiesis in mammal is a complex and highly regulated process in which hematopoietic stem cells (HSCs) give rise to all types of differentiated blood cells. Previous studies have shown that hairy and enhancer of split (HES) repressors are essential regulators of adult HSC development downstream of Notch signaling.

METHODS

In this study, we investigated the role of HES1, a member of HES family, in fetal hematopoiesis using an embryonic hematopoietic specific Hes1 conditional knockout mouse model by using phenotypic flow cytometry, histopathology analysis, and functional in vitro colony forming unit (CFU) assay and in vivo bone marrow transplant (BMT) assay.

RESULTS

We found that loss of Hes1 in early embryonic stage leads to smaller embryos and fetal livers, decreases hematopoietic stem progenitor cell (HSPC) pool, results in defective multi-lineage differentiation. Functionally, fetal hematopoietic cells deficient for Hes1 exhibit reduced in vitro progenitor activity and compromised in vivo repopulation capacity in the transplanted recipients. Further analysis shows that fetal hematopoiesis defects in Hes1fl/flFlt3Cre embryos are resulted from decreased proliferation and elevated apoptosis, associated with de-repressed HES1 targets, p27 and PTEN in Hes1-KO fetal HSPCs. Finally, pharmacological inhibition of p27 or PTEN improves fetal HSPCs function both in vitro and in vivo.

CONCLUSION

Together, our findings reveal a previously unappreciated role for HES1 in regulating fetal hematopoiesis, and provide new insight into the differences between fetal and adult HSC maintenance.

Redox Regulation of Phosphatase and Tensin Homolog by Bicarbonate and Hydrogen Peroxide: Implication of Peroxymonocarbonate in Cell Signaling

Phosphatase and tensin homolog (PTEN) is a negative regulator of the phosphoinositide 3-kinases/protein kinase B (PI3K/AKT) signaling pathway. Notably, its active site contains a cysteine residue that is susceptible to oxidation by hydrogen peroxide (H2O2). This oxidation inhibits the phosphatase function of PTEN, critically contributing to the activation of the PI3K/AKT pathway. Upon the stimulation of cell surface receptors, the activity of NADPH oxidase (NOX) generates a transient amount of H2O2, serving as a mediator in this pathway by oxidizing PTEN. The mechanism underlying this oxidation, occurring despite the presence of highly efficient and abundant cellular oxidant-protecting and reducing systems, continues to pose a perplexing conundrum. Here, we demonstrate that the presence of bicarbonate (HCO3-) promoted the rate of H2O2-mediated PTEN oxidation, probably through the formation of peroxymonocarbonate (HCO4-), and consequently potentiated the phosphorylation of AKT. Acetazolamide (ATZ), a carbonic anhydrase (CA) inhibitor, was shown to diminish the oxidation of PTEN. Thus, CA can also be considered as a modulator in this context. In essence, our findings consolidate the crucial role of HCO3- in the redox regulation of PTEN by H2O2, leading to the presumption that HCO4- is a signaling molecule during cellular physiological processes.

Redox Regulation of PTEN by Reactive Oxygen Species: Its Role in Physiological Processes

Phosphatase and tensin homolog (PTEN) is a tumor suppressor due to its ability to regulate cell survival, growth, and proliferation by downregulating the PI3K/AKT signaling pathway. In addition, PTEN plays an essential role in other physiological events associated with cell growth demands, such as ischemia-reperfusion, nerve injury, and immune responsiveness. Therefore, recently, PTEN inhibition has emerged as a potential therapeutic intervention in these situations. Increasing evidence demonstrates that reactive oxygen species (ROS), especially hydrogen peroxide (H2O2), are produced and required for the signaling in many important cellular processes under such physiological conditions. ROS have been shown to oxidize PTEN at the cysteine residue of its active site, consequently inhibiting its function. Herein, we provide an overview of studies that highlight the role of the oxidative inhibition of PTEN in physiological processes.

Mechanistic study of dual-function inhibitors targeting topoisomerase II and Rad51-mediated DNA repair pathway against castration-resistant prostate cancer

BACKGROUND

Castration-resistant prostate cancer (CRPC) is refractory to hormone treatment and the therapeutic options are continuously advancing. This study aims to discover the anti-CRPC effects and underlying mechanisms of small-molecule compounds targeting topoisomerase (TOP) II and cellular components of DNA damage repair.

METHODS

Cell proliferation was determined in CRPC PC-3 and DU-145 cells using anchorage-dependent colony formation, sulforhodamine B assay and flow cytometric analysis of CFSE staining. Flow cytometric analyses of propidium iodide staining and JC-1 staining were used to examine the population of cell-cycle phases and mitochondrial membrane potential, respectively. Nuclear extraction was performed to detect the nuclear localization of cellular components in DNA repair pathways. Protein expressions were determined using Western blot analysis.

RESULTS

A series of azathioxanthone-based derivatives were synthesized and examined for bioactivities in which WC-A13, WC-A14, WC-A15, and WC-A16 displayed potent anti-CRPC activities in both PC-3 and DU-145 cell models. These WC-A compounds selectively downregulated both TOP IIα and TOP IIβ but not TOP I protein expression. WC-A13, WC-A14, and WC-A15 were more potent than WC-A16 on TOP II inhibition, mitochondrial dysfunction, and induction of caspase cascades indicating the key role of amine-containing side chain of the compounds in determining anti-CRPC activities. Furthermore, WC-A compounds induced an increase of γH2AX and activated ATR-Chk1 and ATM-Chk2 signaling pathways. P21 protein expression was also upregulated by WC-A compounds in which WC-A16 showed the least activity. Notably, WC-A compounds exhibited different regulation on Rad51, a major protein in homologous recombination of DNA in double-stranded break repair. WC-A13, WC-A14, and WC-A15 inhibited, whereas WC-A16 induced, the nuclear translocation of Rad51.

CONCLUSION

The data suggest that WC-A compounds exhibit anti-CRPC effects through the inhibition of TOP II activities, leading to mitochondrial stress-involved caspase activation and apoptosis. Moreover, WC-A13, WC-A14, and WC-A15 but not WC-A16 display inhibitory activities of Rad51-mediated DNA repair pathway which may increase apoptotic effect of CRPC cells.

Bone repair and key signalling pathways for cell-based bone regenerative therapy: A review

Advances in cell-based regenerative therapy create new opportunities for the treatment of bone-related disorders and injuries, by improving the reparative phase of bone healing. Apart from the classical approach of bone grafting, the application of cell-based therapies, particularly stem cells (SCs), has gained a lot of attention in recent years. SCs play an important role in regenerative therapy due to their excellent ability to differentiate into bone-forming cells. Regeneration of new bone is regulated by a wide variety of signalling molecules and intracellular networks, which are responsible for coordinating cellular processes. The activated signalling cascade is significantly involved in cell survival, proliferation, apoptosis, and interaction with the microenvironment and other types of cells within the healing site. Despite the increasing evidence from studies conducted on signalling pathways associated with bone formation, the exact mechanism involved in controlling the differentiation stage of transplanted cells is not well understood. Identifying the key activated pathways involved in bone regeneration may allow for precise manipulation of the relevant signalling molecules within the progenitor cell population to accelerate the healing process. The in-depth knowledge of molecular mechanisms would be advantageous in improving the efficiency of personalised medicine and targeted therapy in regenerative medicine. In this review, we briefly introduce the theory of bone repair mechanism and bone tissue engineering followed by an overview of relevant signalling pathways that have been identified to play an important role in cell-based bone regenerative therapy.

Effect and mechanism of microRNAs on various diabetic wound local cells

The difficulty of wound healing in diabetes mellitus has long been regarded as a thorny problem in the medical field. One of the important reasons is the abnormal function of wound-related cells. A large number of recent studies have shown that microRNA (miR), a noncoding RNA that exists in eukaryotic cells, is closely linked to the functions of various cells in diabetic wound, and ultimately affects the healing of wound. This paper establishes for the first time the connection between miR and wound healing from the cellular perspective and summarizes the effects of various miRs on one or more kinds of wound cells, including their targets and related mechanisms. The abnormal expression of miRs in the wound has certain value for the early diagnosis of diabetic wounds. Moreover, it seems that correcting miRs that are abnormal expressed in the wound or artificially adding miRs that can promote wound healing has an essential therapeutic value.

Differences in the phospholipid profile of melanocytes and melanoma cells irradiated with UVA and treated with cannabigerol and cannabidiol

UV radiation inducing mutations in melanocytes might cause melanoma. As changes in lipid composition and metabolism are associated with many types of cancer including skin cancer, we aimed to evaluate the effects of two phytocannabinoids cannabidiol (CBD) and cannabigerol (CBG), on changes in phospholipid and ceramide (CER) profiles induced by UVA irradiation in human melanocytes and melanoma. UVA radiation caused a significant up-regulation PC, PI and SM species and decrease of CERs content in both types of cells, while up-regulation of PEo was only observed in melanocytes. Exposure of UVA-irradiated melanocytes or melanoma cells to CBD and/or CBG led to significant decrease in relative content of PC, PI and SM specie; however, this effect was more pronounced in cancer cells. Interestingly, only in UVA-irradiated melanocytes and not in melanoma, PEo content was lowered after CBD treatment, while CBG led to additional up-regulation of PEo species. CBD and CBG used together caused decrease of zeta potential, inhibiting PS externalization, and different changes in relative contents of CER and SM species of irradiated and non-irradiated melanoma cells. Obtained results are quite promising due to CBD and CBG abilities to partial reverse pro-cancerogenic changes in phospholipid and CER profiles induced by UVA.

PTEN inhibitor bisperoxovanadium protects against noise-induced hearing loss

Studies have shown that phosphatase and tensin homolog deleted on chromosome ten (PTEN) participates in the regulation of cochlear hair cell survival. Bisperoxovanadium protects against neurodegeneration by inhibiting PTEN expression. However, whether bisperoxovanadium can protect against noise-induced hearing loss and the underlying mechanism remains unclear. In this study, we established a mouse model of noise-induced hearing loss by exposure to 105 dB sound for 2 hours. We found that PTEN expression was increased in the organ of Corti, including outer hair cells, inner hair cells, and lateral wall tissues. Intraperitoneal administration of bisperoxovanadium decreased the auditory threshold and the loss of cochlear hair cells and inner hair cell ribbons. In addition, noise exposure decreased p-PI3K and p-Akt levels. Bisperoxovanadium preconditioning or PTEN knockdown upregulated the activity of PI3K-Akt. Bisperoxovanadium also prevented H₂O₂-induced hair cell death by reducing mitochondrial reactive oxygen species generation in cochlear explants. These findings suggest that bisperoxovanadium reduces noise-induced hearing injury and reduces cochlear hair cell loss.

PTEN Inhibitor Treatment Lowers Muscle Plasma Membrane Damage and Enhances Muscle ECM Homeostasis after High-Intensity Eccentric Exercise in Mice

Exercise-induced muscle damage (EIMD) is a common occurrence in athletes and can lead to delayed onset muscle soreness, reduced athletic performance, and an increased risk of secondary injury. EIMD is a complex process involving oxidative stress, inflammation, and various cellular signaling pathways. Timely and effective repair of the extracellular matrix (ECM) and plasma membrane (PM) damage is critical for recovery from EIMD. Recent studies have shown that the targeted inhibition of phosphatase and tension homolog (PTEN) in skeletal muscles can enhance the ECM environment and reduce membrane damage in Duchenne muscular dystrophy (DMD) mice. However, the effects of PTEN inhibition on EIMD are unknown. Therefore, the present study aimed to investigate the potential therapeutic effects of VO-OHpic (VO), a PTEN inhibitor, on EIMD symptoms and underlying mechanisms. Our findings indicate that VO treatment effectively enhances skeletal muscle function and reduces strength loss during EIMD by upregulating membrane repair signals related to MG53 and ECM repair signals related to the tissue inhibitor of metalloproteinases (TIMPs) and matrix metalloproteinase (MMPs). These results highlight the potential of pharmacological PTEN inhibition as a promising therapeutic approach for EIMD.

Exercise Promotes Tissue Regeneration: Mechanisms Involved and Therapeutic Scope

Exercise has well-recognized beneficial effects on the whole body. Previous studies suggest that exercise could promote tissue regeneration and repair in various organs. In this review, we have summarized the major effects of exercise on tissue regeneration primarily mediated by stem cells and progenitor cells in skeletal muscle, nervous system, and vascular system. The protective function of exercise-induced stem cell activation under pathological conditions and aging in different organs have also been discussed in detail. Moreover, we have described the primary molecular mechanisms involved in exercise-induced tissue regeneration, including the roles of growth factors, signaling pathways, oxidative stress, metabolic factors, and non-coding RNAs. We have also summarized therapeutic approaches that target crucial signaling pathways and molecules responsible for exercise-induced tissue regeneration, such as IGF1, PI3K, and microRNAs. Collectively, the comprehensive understanding of exercise-induced tissue regeneration will facilitate the discovery of novel drug targets and therapeutic strategies.

Bone marrow mesenchymal stem cell-derived exosomal microRNAs target PI3K/Akt signaling pathway to promote the activation of fibroblasts

BACKGROUND

Fibroblast plays a major role in tendon-bone healing. Exosomes derived from bone marrow mesenchymal stem cells (BMSCs) can activate fibroblasts and promote tendon-bone healing via the contained microRNAs (miRNAs). However, the underlying mechanism is not comprehensively understood. Herein, this study aimed to identify overlapped BMSC-derived exosomal miRNAs in three GSE datasets, and to verify their effects as well as mechanisms on fibroblasts.

AIM

To identify overlapped BMSC-derived exosomal miRNAs in three GSE datasets and verify their effects as well as mechanisms on fibroblasts.

METHODS

BMSC-derived exosomal miRNAs data (GSE71241, GSE153752, and GSE85341) were downloaded from the Gene Expression Omnibus (GEO) database. The candidate miRNAs were obtained by the intersection of three data sets. TargetScan was used to predict potential target genes for the candidate miRNAs. Functional and pathway analyses were conducted using the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases, respectively, by processing data with the Metascape. Highly interconnected genes in the protein-protein interaction (PPI) network were analyzed using Cytoscape software. Bromodeoxyuridine, wound healing assay, collagen contraction assay and the expression of COL I and α-smooth muscle actin positive were applied to investigate the cell proliferation, migration and collagen synthesis. Quantitative real-time reverse transcription polymerase chain reaction was applied to determine the cell fibroblastic, tenogenic, and chondrogenic potential.

RESULTS

Bioinformatics analyses found two BMSC-derived exosomal miRNAs, has-miR-144-3p and has-miR-23b-3p, were overlapped in three GSE datasets. PPI network analysis and functional enrichment analyses in the GO and KEGG databases indicated that both miRNAs regulated the PI3K/Akt signaling pathway by targeting phosphatase and tensin homolog (PTEN). In vitro experiments confirmed that miR-144-3p and miR-23b-3p stimulated proliferation, migration and collagen synthesis of NIH3T3 fibroblasts. Interfering with PTEN affected the phosphorylation of Akt and thus activated fibroblasts. Inhibition of PTEN also promoted the fibroblastic, tenogenic, and chondrogenic potential of NIH3T3 fibroblasts.

CONCLUSION

BMSC-derived exosomes promote fibroblast activation possibly through the PTEN and PI3K/Akt signaling pathways, which may serve as potential targets to further promote tendon-bone healing.

PTEN inhibitor VO-OHpic protects endplate chondrocytes against apoptosis and calcification via activating Nrf-2 signaling pathway

Cartilage endplate (CEP) degeneration and calcification is an important contributor to the onset and pathogenesis of intervertebral disc degeneration (IDD). However, the underlying mechanisms of CEP degeneration remain elusive, let alone according treatment strategies to prevent CEP degeneration. Phosphatase and tensin homolog (PTEN) is a tumor suppressor gene that promotes cell apoptosis, and recent studies indicated that PTEN is overexpressed in degenerated intervertebral disc. However, whether direct inhibition of PTEN attenuates CEP degeneration and IDD development remains largely unknown. In the present study, our in vivo experiments demonstrated that VO-OHpic could attenuate IDD progression and CEP calcification. We also found that VO-OHpic inhibited oxidative stress induced chondrocytes apoptosis and degeneration by activating Nrf-2/HO-1 pathway, thus promoted parkin mediated mitophagy process and inhibited chondrocytes ferroptosis, alleviated redox imbalance and eventually improved cell survival. Nrf-2 siRNA transfection significantly reversed the protective effect of VO-OHpic on endplate chondrocytes. In conclusion, our study demonstrated that inhibition of PTEN with VO-OHpic attenuates CEP calcification and IDD progression. Moreover, VO-OHpic protects endplate chondrocytes against apoptosis and degeneration via activating Nrf-2/HO-1 mediated mitophagy process and ferroptosis inhibition. Our results suggest that VO-OHpic may be a potential effective medicine for IDD prevention and treatment.

The orchestrated signaling by PI3Kα and PTEN at the membrane interface

The oncogene PI3Kα and the tumor suppressor PTEN represent two antagonistic enzymatic activities that regulate the interconversion of the phosphoinositide lipids PI(4,5)P2 and PI(3,4,5)P3 in membranes. As such, they are defining components of phosphoinositide-based cellular signaling and membrane trafficking pathways that regulate cell survival, growth, and proliferation, and are often deregulated in cancer. In this review, we highlight aspects of PI3Kα and PTEN interplay at the intersection of signaling and membrane trafficking. We also discuss the mechanisms of PI3Kα- and PTEN- membrane interaction and catalytic activation, which are fundamental for our understanding of the structural and allosteric implications on signaling at the membrane interface and may aid current efforts in pharmacological targeting of these proteins.

Neuronal Death Mechanisms and Therapeutic Strategy in Ischemic Stroke

Ischemic stroke caused by intracranial vascular occlusion has become increasingly prevalent with considerable mortality and disability, which gravely burdens the global economy. Current relatively effective clinical treatments are limited to intravenous alteplase and thrombectomy. Even so, patients still benefit little due to the short therapeutic window and the risk of ischemia/reperfusion injury. It is therefore urgent to figure out the neuronal death mechanisms following ischemic stroke in order to develop new neuroprotective strategies. Regarding the pathogenesis, multiple pathological events trigger the activation of cell death pathways. Particular attention should be devoted to excitotoxicity, oxidative stress, and inflammatory responses. Thus, in this article, we first review the principal mechanisms underlying neuronal death mediated by these significant events, such as intrinsic and extrinsic apoptosis, ferroptosis, parthanatos, pyroptosis, necroptosis, and autophagic cell death. Then, we further discuss the possibility of interventions targeting these pathological events and summarize the present pharmacological achievements.

PTEN expression in human cumulus cells is associated with embryo development competence

Embryo quality determines the success of in vitro fertilization and embryo transfer (IVF-ET) treatment. Biomarkers for the evaluation of embryo quality have some limitations. Apoptosis in cumulus cells (CCs) is important for ovarian function. PTEN (phosphatase and tensin homolog) is a well known tumour suppressor gene that functions as a mediator of apoptosis and is crucial for mammalian reproduction. In the present study, we analyzed the expression level of PTEN in human CCs and aimed to investigate its association with embryo developmental competence in IVF treatment cycles. The PTEN mRNA level in CCs was measured using real-time fluorescence quantitative PCR. The association of the differential expression of PTEN with embryo quality was analyzed. Our data showed that PTEN mRNA levels were significantly decreased in CCs surrounding mature oocytes compared with immature oocytes. Similar changes were found in the analysis of fertilization and blastocyst formation. The speculation that the measurement of PTEN mRNA levels in human CCs would provide a useful tool for selecting oocytes with greater chances to implant into the uterus needs to be further verified through single-embryo transfer in the future. The proapoptotic mechanism of PTEN in human reproduction needs to be further studied.

Losartan Attenuates Atherosclerosis in Uremic Mice by Regulating Treg/Th17 Balance via Mediating PTEN/PI3K/Akt Pathway

INTRODUCTION

Uremia could accelerate atherosclerosis (AS) formation involving Treg/Th17 imbalance. Losartan regulates the imbalance between regulatory T cells (Treg cells) and T helper 17 cells (Th17 cells). However, their interactions in uremia accelerated AS (UAAS) remained poorly understood.

METHODS

UAAS mice model was established, and after losartan and VO-OHpic (VO, phosphatase and tensin homolog [PTEN] inhibitor) injection, biological indexes, and inflammatory cytokines (transforming growth factor-β1, TGF-β1; interleukin-10 [IL-10]; IL-17 and IL-6) levels were determined using enzyme-linked immunosorbent assay. Pathological changes on aorta were observed using hematoxylin-eosin staining. Percentages of Treg cells (CD4+CD25+Foxp3+) and Th17 cells (CD4+IL-17+) in total CD4+ T cells were determined using flow cytometry. PTEN expressions were measured using Western blot, quantitative real-time polymerase chain reaction, and immunohistochemistry staining as needed.

RESULTS

After UAAS mice model construction, biological indexes (urea, cholesterol, and triglycerides) levels were increased, and aortic atherosclerotic plaque was formed. In UAAS mice, in total CD4+ T cells, Treg cells percentage was decreased yet Th17 cells percentage was increased, and TGF-β1 and IL-10 levels were downregulated yet IL-17 and IL-6 levels were upregulated. An opposite effect was found after losartan treatment. PTEN was downregulated in UAAS mice, and suppressing PTEN reversed the alleviating effects of losartan in UAAS mice.

CONCLUSION

Losartan attenuated UAAS in mice by regulating Treg/Th17 cells balance via mediating PTEN/PI3K/Akt pathway, providing possible therapeutic method for UAAS in clinical practice.

The biochemical and clinical implications of phosphatase and tensin homolog deleted on chromosome ten in different cancers

Phosphatase and tensin homolog deleted on chromosome ten (PTEN) is widely known as a tumor suppressor gene. It is located on chromosome 10q23 with 200 kb, and has dual activity of both protein and lipid phosphatase. In addition, as a targeted gene in multiple pathways, PTEN has a variety of physiological activities, such as those regulating the cell cycle, inducing cell apoptosis, and inhibiting cell invasion, etc. The PTEN gene have been identified in many kinds of cancers due to its mutations, deletions and inactivation, such as lung cancer, liver cancer, and breast cancer, and they are closely connected with the genesis and progression of cancers. To a large extent, the tumor suppressive function of PTEN is realized through its inhibition of the PI3K/AKT signaling pathway which controls cells apoptosis and development. In addition, PTEN loss has been associated with the prognosis of many cancers, such as lung cancer, liver cancer, and breast cancer. PTEN gene is related to many cancers and their pathological development. On the basis of a large number of related studies, this study describes in detail the structure, regulation, function and classical signal pathways of PTEN, as well as the relationship between various tumors related to PTEN. In addition, some drug studies targeting PTEN/PI3K/AKT/mTOR are also introduced in order to provide some directions for experimental research and clinical treatment of tumors.

Neuropathic Pain: Biomolecular Intervention and Imaging via Targeting Microglia Activation

Many diseases, including cancer, can lead to neuropathic pain (NP). NP is one of the accompanying symptoms of suffering in many conditions and the life quality of NP patient is seriously affected. Due to complex causes, the effects of clinical treatments have been very unsatisfactory. Many experts have found that neuron-microglia interaction plays an essential role in NP occurrence and development. Therefore, the activation of microglia, related inflammatory mediators and molecular and cellular signaling pathways have become the focus of NP research. With the help of modern functional imaging technology, advanced pre-and clinical studies have been carried out and NP interventions have been attempted by using the different pharmaceuticals and the extracted active components of various traditional herbal medicines. In this communication, we review the mechanism of microglia on NP formation and treatment and molecular imaging technology's role in the clinical diagnosis and evaluation of NP therapies.

Hsa_circ_0066523 promotes the proliferation and osteogenic differentiation of bone mesenchymal stem cells by repressing PTEN

Aims

Circular RNAs (circRNAs) are a novel type of non-coding RNA that plays major roles in the development of diverse diseases including osteonecrosis of the femoral head (ONFH). Here, we explored the impact of hsa_circ_0066523 derived from forkhead box P1 (FOXP1) (also called circFOXP1) on bone mesenchymal stem cells (BMSCs), which is important for ONFH development.

Methods

RNA or protein expression in BMSCs was analyzed by quantitative real-time polymerase chain reaction (qRT-PCR) or western blot, respectively. Cell Counting Kit 8 (CCK8) and 5-ethynyl-2’-deoxyuridine (EdU) were used to analyze cell proliferation. Alkaline phosphatase (ALP) activity, ALP staining, and Alizarin Red S staining were employed to evaluate the osteoblastic differentiation. Chromatin immunoprecipitation (ChIP), luciferase reporter, RNA pull down, and RNA immunoprecipitation (RIP) assays were combined for exploring molecular associations.

Results

Circ_0066523 was upregulated in osteogenic induction process of BMSCs. Silencing circ_0066523 restrained the proliferation and osteogenic differentiation of BMSCs. Mechanistically, circ_0066523 activated phosphatidylinositol-4,5-bisphosphate 3-kinase / AKT serine/threonine kinase 1 (PI3K/AKT) pathway via recruiting lysine demethylase 5B (KDM5B) to epigenetically repress the transcription of phosphatase and tensin homolog (PTEN). Functionally, AKT signalling pathway agonist or PTEN knockdown counteracted the effects of silenced circ_0066523 on BMSC proliferation and differentiation.

Conclusion

Circ_0066523 promotes the proliferation and differentiation of BMSCs by epigenetically repressing PTEN and therefore activating AKT pathway. This finding might open new avenues for the identification of therapeutic targets for osteoblast differentiation related diseases such as ONFH.

Cite this article: Bone Joint Res 2021;10(8):526–535.

MicroRNA-26a-3p rescues depression-like behaviors in male rats via preventing hippocampal neuronal anomalies

Depression is a neuropsychiatric disease associated with neuronal anomalies within specific brain regions. In the present study, we screened microRNA (miRNA) expression profiles in the dentate gyrus (DG) of the hippocampus and found that miR-26a-3p was markedly downregulated in a rat model of depression, whereas upregulation of miR-26a-3p within DG regions rescued the neuronal deterioration and depression-like phenotypes resulting from stress exposure, effects that appear to be mediated by the PTEN pathway. The knockdown of miR-26a-3p in DG regions of normal control rats induced depression-like behaviors, effects that were accompanied by activation of the PTEN/PI3K/Akt signaling pathway and neuronal deterioration via suppression of autophagy, impairments in synaptic plasticity, and promotion of neuronal apoptosis. In conclusion, these results suggest that miR-26a-3p deficits within the hippocampal DG mediated the neuronal anomalies contributing to the display of depression-like behaviors. This miRNA may serve as a potential therapeutic target for the treatment of depression.

Bone marrow-mesenchymal stem cell-derived exosomal microRNA-141 targets PTEN and activates β-catenin to alleviate myocardial injury in septic mice

BACKGROUND

Mesenchymal stem cells (MSCs) and their derived exosomes have shown potentials in the control of myocardial dysfunction. This study aimed to reveal the function of bone marrow (BM)-MSC-derived exosomes in sepsis-induced myocardial injury and the molecular mechanism.

METHODS

BM-MSC-derived exosomes were obtained and identified. A mouse model with sepsis was induced by cecalligation puncture (CLP) and treated with exosomes. The myocardial function of mice, the production of creatine kinase MB (CK-MB) and lactate dehydrogenase (LDH) in serum, the phosphorylation of a key myocardial contractility-related protein phospholamban (PLB), and the pathological changes in the myocardial tissues were examined. A microRNA (miRNA) microarray analysis was performed to examine the candidate miRNAs carried by the exosomes. Rescue experiments were conducted to validate the involvement of miR-141.

RESULTS

CLP treatment led to sepsis and notably reduced the myocardial function in mice. Further treatment of BM-MSC-derived exosomes alleviated the CLP-induced myocardial impairment, production of CK-MB and LDH, and inflammatory infiltration and cell apoptosis in mouse myocardial tissues, and restored the PLB phosphorylation. miR-141 was the most upregulated miRNA in the myocardial tissues after exosome treatment. Downregulation of miR-141 blocked the myocardium-protective functions of the exosomes. miR-141 was found to bind to and suppress PTEN expression, which further enhanced the activity of β-catenin.

CONCLUSION

This study suggested that BM-MSC derived exosomes ameliorates myocardial injury in septic mice through conveying miRNA-141 and regulating the PTEN/β-catenin axis, and exosomes may serve as promising tools for the management of myocardial injury induced by sepsis or other factors.

SPOP-PTEN-SUFU axis promotes progression of clear cell renal cell carcinoma via activating SHH and WNT pathway

Although E3 ligase Speckle type BTB/POZ protein (SPOP) promotes tumorigenesis by acting as a key regulatory hub in clear cell renal cell carcinoma (ccRCC), the detailed molecular mechanism remains unclear. Here, we demonstrate that a well-known tumor suppressor, Suppressor of Fused (SUFU), is downregulated by SPOP. Interestingly, this downregulation depends on cullin-3(Cul3)-SPOP E3 ligase, but SUFU is not a direct substrate of SPOP. Phosphatase and tensin homolog (PTEN), a ubiquitinated substrate of SPOP, is involved in SPOP-mediated SUFU reduction. Importantly, inhibition of SUFU leads to elevated SHH and WNT signaling, consequently rescuing the reduced proliferation, migration, and invasion abilities of ccRCC cells caused by SPOP-knockdown. Moreover, combinatorial treatment with SHH and WNT inhibitors shows more effective for suppressing ccRCC cell proliferation and aggressiveness. These findings demonstrate that a novel SPOP–PTEN–SUFU axis promotes ccRCC carcinogenesis by activating SHH and WNT pathway, providing a new treatment strategy for ccRCC.

Decitabine inhibits the proliferation of human T-cell acute lymphoblastic leukemia molt4 cells and promotes apoptosis partly by regulating the PI3K/AKT/mTOR pathway

T cell acute lymphoblastic leukemia (T-ALL) is a highly aggressive hematological cancer; however, there is a lack of effective chemotherapeutic or targeted drugs for the treatment of T-ALL. Decitabine is a DNA demethylation agent but it has not been used for T-ALL treatment. Therefore, the present study aimed to assess the inhibitory effect of decitabine on T-ALL molt4 cells and determine its regulatory role in the PI3K/AKT/mTOR pathway. Molt4 cells were stimulated with decitabine in vitro, after which cell proliferation, apoptosis and cell cycle analyses were performed to assess cell viability. Subcellular morphology was observed using transmission electron microscopy. Expression levels of phosphate and tension homology (PTEN), genes involved in the PI3K/AKT/mTOR pathway and the corresponding downstream genes were analyzed using reverse transcription-quantitative PCR and western blotting. The results showed that decitabine induced apoptosis, inhibited proliferation and arrested molt4 cells in the G₂ phase. Following decitabine intervention, an increase in the number of lipid droplets, autophagosomes and mitochondrial damage was observed. At concentrations of 1 and 10 µM, decitabine downregulated the expression of PI3K, AKT, mTOR, P70S6 and eukaryotic initiating factor 4E-binding protein 1, which in turn upregulated PTEN expression; however, 50 µM decitabine downregulated PTEN levels. Overall, these results demonstrated that decitabine reduced the viability of molt4 cells partly by inhibiting the PI3K/AKT/mTOR pathway via PTEN, especially at low decitabine concentrations.

Critical implication of the PTEN/PI3K/AKT pathway during BMP2-induced heterotopic ossification

Heterotopic ossification (HO) is characterized by extraskeletal ossification in soft tissue. Thus far, there is a lack of effective drug therapy against HO. Loss of PTEN in osteoblasts has been reported to accumulate bone mass in skeletal development and promote fracture healing in association with the activation of the PI3K/AKT pathway. However, the role of the PTEN/PI3K/AKT signaling in HO pathogenesis remains unknown. The present study investigated the implication of this pathway during BMP2-induced osteogenic differentiation and ectopic bone formation. It was shown that overexpression of PTEN inhibited proliferation but stimulated apoptosis in mesenchymal pluripotent C3H10T1/2 cells. PTEN also inhibited BMP2-induced osteoblast differentiation, whereas BMP2 repressed PTEN expression and subsequently activated PI3K/AKT. The PI3K inhibitor, LY294002, blocked BMP2-induced osteoblastogenesis, suggesting that the PI3K/AKT pathway is critically required for BMP2 to initiate osteoblastogenesis. In vivo, implantation of BMP2 in muscle induced ectopic endochondral ossification. Strikingly, this bone-forming capacity was notably suppressed by the PI3K inhibitor LY294002. Hence, the results of the present study demonstrated that the PI3K/AKT signaling activity is indispensable for BMP2 to induce ectopic new bone. Targeting the PI3K/AKT pathway using inhibitor(s) may represent a potential molecular therapy for the treatment against HO.

Differential Regulation of mTOR Complexes with miR-302a Attenuates Myocardial Reperfusion Injury in Diabetes

Persistent activation of mTOR (mammalian target of rapamycin) in diabetes increases the vulnerability of the heart to ischemia/reperfusion (I/R) injury. We show here that infusion of rapamycin (mTOR inhibitor) at reperfusion following ischemia reduced myocardial infarct size and apoptosis with restoration of cardiac function in type 1 diabetic rabbits. Likewise, treatment with rapamycin protected hyperglycemic human-pluripotent-stem-cells-derived cardiomyocytes (HG-hiPSC-CMs) following simulated ischemia (SI) and reoxygenation (RO). Phosphorylation of S6 (mTORC1 marker) was increased, whereas AKT phosphorylation (mTORC2 marker) and microRNA-302a were reduced with concomitant increase of its target, PTEN, following I/R injury in diabetic heart and HG-hiPSC-CMs. Rapamycin inhibited mTORC1 and PTEN, but augmented mTORC2 with restoration of miRNA-302a under diabetic conditions. Inhibition of miRNA-302a blocked mTORC2 and abolished rapamycin-induced protection against SI/RO injury in HG-hiPSC-CMs. We conclude that rapamycin attenuates reperfusion injury in diabetic heart through inhibition of PTEN and mTORC1 with restoration of miR-302a-mTORC2 signaling.

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miR-302a and AKT phosphorylation are suppressed in post-ischemic diabetic heart

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Negative regulator of insulin signaling, PTEN, is induced after ischemia reperfusion

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miRNA-302a-mimic abolishes ischemic injury in hyperglycemic human iPS cardiocytes

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Rapamycin treatment restores miR-302a-mTORC2 cardioprotective signaling in diabetes

Discovery of Novel Dual Extracellular Regulated Protein Kinases (ERK) and Phosphoinositide 3-Kinase (PI3K) Inhibitors as a Promising Strategy for Cancer Therapy

Concomitant inhibition of MAPK and PI3K signaling pathways has been recognized as a promising strategy for cancer therapy, which effectively overcomes the drug resistance of MAPK signaling pathway-related inhibitors. Herein, we report the scaffold-hopping generation of a series of 1H-pyrazolo[3,4-d]pyrimidine dual ERK/PI3K inhibitors. Compound 32d was the most promising candidate, with potent inhibitory activities against both ERK2 and PI3Kα which displays superior anti-proliferative profiles against HCT116 and HEC1B cancer cells. Meanwhile, compound 32d possessed acceptable pharmacokinetic profiles and showed more efficacious anti-tumor activity than GDDC-0980 and the corresponding drug combination (BVD-523 + GDDC-0980) in HCT-116 xenograft model, with a tumor growth inhibitory rate of 51% without causing observable toxic effects. All the results indicated that 32d was a highly effective anticancer compound and provided a promising basis for further optimization towards dual ERK/PI3K inhibitors.

PTEN inhibitor improves vascular remodeling and cardiac function after myocardial infarction through PI3k/Akt/VEGF signaling pathway

Background

Myocardial infarction (MI) is the leading cause of death from cardiovascular disease (CVD). Currently, the efficacy for MI treatment remains unsatisfactory. Therefore, it is urgent to develop a novel therapeutic strategy.

Methods

Left anterior descending arteries (LAD) of mice were ligated to induce MI. Another set of mice were intravenously injected with PTEN inhibitor BPV (1 mg/kg) 1 h after LAD ligation and continued to receive BPV injection daily for the following 6 days. Mice were performed echocardiography 14 days after surgery.

Results

Mice in MI group displayed an increased expression of PTEN with impaired cardiac function, enhanced cardiomyocyte apoptosis and decreased angiogenesis. BPV treatment significantly improved cardiac function, with reduced cardiomyocyte apoptosis, promoted angiogenesis, and activated PI3K/Akt/vascular endothelial growth factor (VEGF) signaling pathway.

Conclusion

PTEN inhibitor BPV could effectively prevent myocardial infarction in mice, highlighting its potential as a candidate therapeutic drug.

Lipid metabolic Reprogramming: Role in Melanoma Progression and Therapeutic Perspectives

Simple Summary

Melanoma is a devastating skin cancer characterized by an impressive metabolic plasticity. Melanoma cells are able to adapt to the tumor microenvironment by using a variety of fuels that contribute to tumor growth and progression. In this review, the authors summarize the contribution of the lipid metabolic network in melanoma plasticity and aggressiveness, with a particular attention to specific lipid classes such as glycerophospholipids, sphingolipids, sterols and eicosanoids. They also highlight the role of adipose tissue in tumor progression as well as the potential antitumor role of drugs targeting critical steps of lipid metabolic pathways in the context of melanoma.

Abstract

Metabolic reprogramming contributes to the pathogenesis and heterogeneity of melanoma. It is driven both by oncogenic events and the constraints imposed by a nutrient- and oxygen-scarce microenvironment. Among the most prominent metabolic reprogramming features is an increased rate of lipid synthesis. Lipids serve as a source of energy and form the structural foundation of all membranes, but have also emerged as mediators that not only impact classical oncogenic signaling pathways, but also contribute to melanoma progression. Various alterations in fatty acid metabolism have been reported and can contribute to melanoma cell aggressiveness. Elevated expression of the key lipogenic fatty acid synthase is associated with tumor cell invasion and poor prognosis. Fatty acid uptake from the surrounding microenvironment, fatty acid β-oxidation and storage also appear to play an essential role in tumor cell migration. The aim of this review is (i) to focus on the major alterations affecting lipid storage organelles and lipid metabolism. A particular attention has been paid to glycerophospholipids, sphingolipids, sterols and eicosanoids, (ii) to discuss how these metabolic dysregulations contribute to the phenotype plasticity of melanoma cells and/or melanoma aggressiveness, and (iii) to highlight therapeutic approaches targeting lipid metabolism that could be applicable for melanoma treatment.

PTEN Inhibition Ameliorates Muscle Degeneration and Improves Muscle Function in a Mouse Model of Duchenne Muscular Dystrophy

Duchenne muscular dystrophy (DMD) is caused by a mutation of the muscle membrane protein dystrophin and characterized by severe degeneration of myofibers, progressive muscle wasting, loss of mobility, and, ultimately, cardiorespiratory failure and premature death. Currently there is no cure for DMD. Herein, we report that skeletal muscle-specific knockout (KO) of the phosphatase and tensin homolog (Pten) gene in an animal model of DMD (mdx mice) alleviates myofiber degeneration and restores muscle function without increasing tumor incidence. Specifically, Pten KO normalizes myofiber size and prevents muscular atrophy, and it improves grip strength and exercise performance in mdx mice. Pten KO also reduces fibrosis and inflammation, and it ameliorates muscle pathology in mdx mice. Unbiased RNA sequencing reveals that Pten KO upregulates extracellular matrix and basement membrane components positively correlated with wound healing and suppresses negative regulators of wound healing and lipid biosynthesis, thus improving the integrity of muscle basement membrane at the ultrastructural level. Importantly, pharmacological inhibition of PTEN similarly ameliorates muscle pathology and improves muscle integrity and function in mdx mice. Our findings provide evidence that PTEN inhibition may represent a potential therapeutic strategy to restore muscle function in DMD.

Exosomes derived from atorvastatin-pretreated MSC accelerate diabetic wound repair by enhancing angiogenesis via AKT/eNOS pathway

Background

Mesenchymal stem cell (MSC)-derived exosomes emerge as promising candidates for treating delayed wound healing in diabetes due to the promotion of angiogenesis. Preconditioned MSC with chemical or biological factors could possibly enhance the biological activities of MSC-derived exosomes. The purpose of this research focused on whether exosomes derived from the bone marrow MSC (BMSC) pretreated with atorvastatin (ATV), could exhibit better pro-angiogenic ability in diabetic wound healing or not and its underlying molecular mechanism.

Methods

We isolated exosomes from non-pretreated BMSC (Exos) and ATV pretreated BMSC (ATV-Exos) and evaluated their characterization by transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA) and Western blotting. In vivo, we made full-thickness skin defects in streptozotocin (STZ)-induced diabetic rats and the defects received multiple-point injection with PBS, Exos, or ATV-Exos. Two weeks later, histological analysis was conducted to evaluate the impact of different treatments on wound healing and the neovascularization was measured by micro-CT. In vitro, cell proliferation, migration, tube formation, and vascular endothelial growth factor (VEGF) secretion were measured in human umbilical vein endothelial cells (HUVEC). The role of miRNAs and AKT/eNOS signaling pathway in the promoted angiogenesis of ATV-Exos were assessed with their inhibitors.

Results

No significant difference in morphology, structure, and concentration was observed between ATV-Exos and Exos. In STZ-induced diabetic rats, ATV-Exos exhibited excellent abilities in facilitating the wound regeneration by promoting the formation of blood vessels compared with Exos without influencing liver and kidney function. Meanwhile, ATV-Exos promoted the proliferation, migration, tube formation, and VEGF level of endothelial cells in vitro. And AKT/eNOS pathway was activated by ATV-Exos and the pro-angiogenic effects of ATV-Exo were attenuated after the pathway being blocked. MiR-221-3p was upregulated by ATV-Exos stimulation, and miR-221-3p inhibitor suppressed the pro-angiogenesis effect of ATV-Exos.

Conclusions

Exosomes originated from ATV-pretreated MSCs might serve as a potential strategy for the treatment of diabetic skin defects through enhancing the biological function of endothelial cells via AKT/eNOS pathway by upregulating the miR-221-3p.

Role and mechanism of PI3K/AKT/FoxO1/PDX-1 signaling pathway in functional changes of pancreatic islets in rats after severe burns

AIMS

Studies on diabetes mellitus have shown that the phosphoinositide 3-kinase (PI3K)/serine threonine kinase (AKT)/forkhead box protein O1 (FoxO1) signaling pathway can regulate insulin secretion by modulating the expression of pancreatic and duodenal homeobox-1 (PDX-1). Therefore, it was hypothesized that the pathway also played an important role in functional abnormalities of pancreatic islets after severe burns. This study aimed to explore the role and mechanism of the PI3K/AKT/FoxO1/PDX-1 signaling pathway in functional changes of pancreatic islets in rats post severe burns.

MAIN METHODS

Rats were grouped, subjected to full thickness burn injuries involving 50% total body surface area (TBSA), and injected intraperitoneally with BPV (HOpic) (0.6 mg/kg) or DMSO (0.55 mg/kg) once a day for three days. Glucose metabolism related indexes were measured by the glucometer, transmission electron microscopy (TEM) and enzyme-linked immunosorbent assay (ELISA). PI3K/AKT/FoxO1/PDX-1 signaling pathway related indexes were detected through immunofluorescence, western blot and RT-qPCR analyses.

KEY FINDINGS

Dysglycemia and impaired insulin secretion occurred in rats, the activity of the PI3K/AKT/FoxO1/PDX-1 signaling pathway in the islets fell, and PDX-1 was translocated from the nucleus to the cytoplasm post severe burns. When BPV (HOpic) was used, glucose metabolism and insulin secretion were improved, the activity of the PI3K/AKT/FoxO1/PDX-1 signaling pathway in the islets was up-regulated, and PDX-1 was redistributed from the cytoplasm to the nucleus.

SIGNIFICANCE

The activity of the PI3K/AKT/FoxO1/PDX-1 signaling pathway declined following severe burns. When its activity was up-regulated, insulin secretion could be improved, thus ameliorating hyperglycemia.

The Tumor Suppressor PTEN as Molecular Switch Node Regulating Cell Metabolism and Autophagy: Implications in Immune System and Tumor Microenvironment

Recent studies conducted over the past 10 years evidence the intriguing role of the tumor suppressor gene Phosphatase and Tensin Homolog deleted on Chromosome 10 PTEN in the regulation of cellular energy expenditure, together with its capability to modulate proliferation and survival, thus expanding our knowledge of its physiological functions. Transgenic PTEN mice models are resistant to oncogenic transformation, present decreased adiposity and reduced cellular glucose and glutamine uptake, together with increased mitochondrial oxidative phosphorylation. These acquisitions led to a novel understanding regarding the role of PTEN to counteract cancer cell metabolic reprogramming. Particularly, PTEN drives an “anti-Warburg state” in which less glucose is taken up, but it is more efficiently directed to the mitochondrial Krebs cycle. The maintenance of cellular homeostasis together with reduction of metabolic stress are controlled by specific pathways among which autophagy, a catabolic process strictly governed by mTOR and PTEN. Besides, a role of PTEN in metabolic reprogramming and tumor/stroma interactions in cancer models, has recently been established. The genetic inactivation of PTEN in stromal fibroblasts of mouse mammary glands, accelerates breast cancer initiation and progression. This review will discuss our novel understanding in the molecular connection between cell metabolism and autophagy by PTEN, highlighting novel implications regarding tumor/stroma/immune system interplay. The newly discovered action of PTEN opens innovative avenues for investigations relevant to counteract cancer development and progression.

Correlation Between Single Nucleotide Polymorphisms of an miRNA Binding Site in the 3'UTR of PTEN and Risk of Cervical Cancer Among the Han Chinese

Objective: To analyze the association between a single nucleotide polymorphism (SNP) in the 3' untranslated region (UTR) of the phosphatase and tensin homolog (PTEN) gene, that is within a microRNA (miRNA) binding site, and the risk of Chinese Han cervical cancer. Methods: A case-control study was carried out to analyze the genotype of the PTEN rs34140758 locus in 210 surgically treated, Han Chinese, cervical cancer patients and 210 healthy controls. The levels of the miRNAs hsa-miR-586 and hsa-miR-622 and the PTEN mRNA were analyzed by real-time reverse transcription-quantitative polymerase chain reaction in the cancerous and adjacent normal tissues from all cases. HeLa cells were transfected with the miRNAs, hsa-miR-586 and hsa-miR-622, to analyze their effects on PTEN gene expression. Results: After adjusting for age, body-mass index, alcohol consumption, smoking, and familial history of cancer, the PTEN rs34140758 A allele carriers were 1.47 times more likely to suffer from cervical cancer than the C allele carriers (odds ratio [OR] = 1.47, 95% confidence interval [CI]: 1.17-1.72, p = 0.001). Both hsa-miR-586 and hsa-miR-622 were highly expressed in the cancerous tissues of the cervical cancer patients, whereas PTEN expression was low. HeLa cell transfection experiments showed that hsa-miR-586 and hsa-miR-622 inhibited PTEN gene expression. The results of a dual-luciferase reporter assay showed that the PTEN gene is a target for both hsa-miR-586 and hsa-miR-622. Conclusion: The PTEN 3'UTR rs34140758 locus SNP is associated with the risk of cervical cancer in the Han Chinese population. The molecular mechanism may be that the rs34140758 SNP affects the regulation of PTEN gene expression through interaction with the hsa-miR-586 and hsa-miR-622 miRNAs.

Association of genetic variations in phosphatase and tensin homolog (PTEN) gene with polycystic ovary syndrome in South Indian women: a case control study

PURPOSE

The purpose of the study was to investigate the association between gene phosphate and tensin homolog (PTEN) single nucleotide polymorphisms (SNPs) and risk of developing polycystic ovary syndrome (PCOS) in South Indian women. PTEN is one of the most important tumor suppressor genes that regulate cell proliferation, migration, and death. It is also involved in the maintenance of genome stability. PCOS is one of the most common endocrine disorders among women of reproductive age. It is a heterogeneous syndrome characterized by abnormal reproductive cycles, irregular ovulation, hormonal imbalance, hyperandrogenism, acne and hirsutism.

RESEARCH QUESTION

What is the association status of PTEN SNPs with PCOS?

METHODS

A total of 240 subjects were recruited in this case-control study comprising 110 patients with PCOS and 130 individuals without PCOS. All the subjects were of South Indian origin. The genotyping of PTEN SNPs (rs1903858 A/G, rs185262832G/A and rs10490920T/C) was carried out on DNA from subjects by polymerase chain reaction (PCR) and sequencing analysis. Haplotype frequencies for multiple loci and the standardized disequilibrium coefficient (D') for pairwise linkage disequilibrium (LD) were surveyed by Haploview Software.

RESULTS

Our results showed significant increase in the frequencies of rs1903858 A/G (P = 0.0016), rs185262832 G/A (P = 0.0122) and rs10490920 T/C (P = 0.0234) genotypes and alleles in cases compared to controls.

CONCLUSION

The PTEN (rs1903858A/G, rs185262832G/A and rs10490920T/C) gene polymorphisms may constitute an inheritable risk factor for PCOS in South Indian women.

PTEN inhibitor VO-OHpic suppresses TSC2- / - MEFs proliferation by excessively inhibiting autophagy via the PTEN/PRAS40 pathway

Tuberous sclerosis complex (TSC) is a relatively rare autosomal dominant disease which involves multiple organs, including the brain, kidney, lung, skin and heart. Renal angiomyolipomas (RAML) are the main causes of mortality in patients with TSC. The preferred treatment for RAML is the use of mTOR inhibitors, but the efficacy of these are not satisfactory. Therefore, an alternative treatment is urgently required. Autophagy levels decline in TSC associated cortical tubers, and the inhibition of autophagy in animal or cell models of TSC may suppress tumor development and cell proliferation. PTEN is a protein tyrosine phosphatase and can inhibit the activation of Akt. In the present study, it was indicated that the PTEN inhibitor, hydroxyl(oxo)vanadium 3-hydroxypiridine-2-carboxylic acid (VO-OHpic), suppressed proliferation and growth of TSC2^-/- murine embryonic fibroblasts (MEFs) by further inhibiting autophagy of cells. The expression levels of human microtubule-associated protein 1 light chain 3-I (LC3-I) and LC3-II, which are autophagy associated proteins, were demonstrated to decline following VO-OHpic treatment. The expression levels of phosphorylated proline-rich Akt substrate 40 kDa (PRAS40) also decreased in TSC2^-/- MEFs treated with VO-OHpic. The PTEN inhibitor may inhibit the proliferation of TSC2^-/- MEFs through the PTEN-PRAS40 pathway by excessively inhibiting autophagy, without the dependence of the Ras homolog, mTORC1 binding/mTOR pathway. PTEN may be a potential therapeutic target for the treatment of TSC. Further in vivo studies are required to confirm these results.

Pharmacological PTEN inhibition: potential clinical applications and effects in tissue regeneration

Although the human body can heal, it takes time, and slow healing and chronic wounds often occur. Thus, identifying novel therapies to aid regeneration is needed. Here, we conducted a systematic review following the Preferred Reporting Items for Systematic Reviews guidelines and assessed preclinical studies on phosphatase and tensin homolog (PTEN) inhibitors and their effects on tissue repair and regeneration. In conditions associated with neurodegeneration, tissue injury and ischemia, the PTEN-regulated PI3K/AKT signaling pathway is activated. The use of PTEN inhibitors resulted in better tissue response by reducing the healing time and lesion sizes or inducing neuronal regeneration. Notably, all studies included in this systematic review indicated that pharmacological inhibition of PTEN enhanced the repair process of the eye, lung, muscle and nervous system.

Long Non-coding RNA Gas5 Is Associated With Preeclampsia and Regulates Biological Behaviors of Trophoblast via MicroRNA-21

Preeclampsia is a lethal pregnancy specific hypertensive disorder involving multisystem. Despite extensive studies to investigate the causes of preeclampsia, the pathogenesis still remains largely unknown. Long non-coding RNAs (lncRNAs) are a diverse class of non-translated RNAs which play a crucial part in various biological phenomena. Although lncRNA Growth Arrest-Specific 5 (GAS5) aberrantly expressed in multiple cancer tissues and is implicated in multiple biological processes of tumor cells, little is known about its role in preeclampsia. In this study, 40 patients with preeclampsia and 32 gestational age matched normotension pregnant women were recruited. Using quantitative real-time polymerase chain reaction (qRT-PCR), we found higher expression of GAS5 in placenta of preclamsia affected women. The level of GAS5 existed strongly in correlation with Thrombin Time indicating coagulation function and other clinical parameters by Pearson correlation analysis. Then we constructed the GAS5 lentivirus expression vectors and transfected into human trophoblast cell lines HTR-8/SVneo and JEG-3. Using in vitro cell culture studies, we found an inhibited effect of GAS5 on proliferative ability, migratory ability and invasive ability however; no effect on apoptosis was detected. Further mechanistic analysis found that GAS5 modulated microRNA-21 (miR-21) in an opposite variation tendency by qRT-PCR and rescue experiment. In addition, inhibition of GAS5 promoted the activation of PI3K/AKT signaling pathway and its downstream proteins covering MMP-9 and TP53 as evident from our qRT-PCR and western blot analyses. Thus, we suggested that GAS5 might involve in pregnancy with preeclampsia by influencing the biological functions of trophoblast cells through the regulation of miR-21 and activation of PI3K/AKT signaling pathway and its downstream targets, which may contribute to reveal the nature of preeclampsia.

Tissue inhibitor of metalloproteinase 1 suppresses growth and differentiation of osteoblasts and differentiation of osteoclasts by targeting the AKT pathway

Tissue inhibitor of metalloproteinase 1 (TIMP1) has various biological activities including the regulation of cell growth and differentiation. However, its role in bone homeostasis and remodeling remains poorly understood. In this study, we investigate the effects of TIMP1 on osteoblast and osteoclast activity at both cellular and molecular level using siRNA-mediated knockdown technique. Our results show that knockdown of TIMP1 stimulates proliferation and survival, but decreases apoptosis in osteoblastic MC3T3-E1 cells, suggesting that TIMP1 inhibits cell growth. TIMP1 also dampens differentiation of committed osteoblasts, as well as osteoblastogenesis of bone marrow-derived mesenchymal stem cells (BMSCs). We further show that the modulation of TIMP1 on osteoblast activity is independent of its MMP inhibition. Importantly, we uncover that TIMP1 suppresses osteoblast growth and differentiation by targeting the AKT pathway, and this is associated with TIMP1-mediated induction of PTEN via its binding to the cell surface receptor CD44. Therefore, our results highlight a novel TIMP1/CD44/PTEN/AKT signaling nexus that functions as a suppressor of osteoblast activity. Moreover, we show that TIMP1 also inhibits osteoclast differentiation in osteoclast precursor RAW 264.7 cells by targeting the AKT. In conclusion, our results demonstrate that TIMP1 can act as a suppressor of growth and differentiation of osteoblasts and differentiation of osteoclasts through the negative regulation of the AKT pathway. We propose that TIMP1 may serve as a potential target for low bone mass-related skeletal diseases, such as osteoporosis.

Growth Hormone Neuroprotection Against Kainate Excitotoxicity in the Retina is Mediated by Notch/PTEN/Akt Signaling

Purpose

In the retina, growth hormone (GH) promotes axonal growth, synaptic restoration, and protective actions against excitotoxicity. Notch signaling pathway is critical for neural development and participates in the retinal neuroregenerative process. We investigated the interaction of GH with Notch signaling pathway during its neuroprotective effect against excitotoxic damage in the chicken retina.

Methods

Kainate (KA) was used as excitotoxic agent and changes in the mRNA expression of several signaling markers were determined by qPCR. Also, changes in phosphorylation and immunoreactivity were determined by Western blotting. Histology and immunohistochemistry were performed for morphometric analysis. Overexpression of GH was performed in the quail neuroretinal-derived immortalized cell line (QNR/D) cell line. Exogenous GH was administered to retinal primary cell cultures to study the activation of signaling pathways.

Results

KA disrupted the retinal cytoarchitecture and induced significant cell loss in several retinal layers, but the coaddition of GH effectively prevented these adverse effects. We showed that GH upregulates the Notch signaling pathway during neuroprotection leading to phosphorylation of the PI3K/Akt signaling pathways through downregulation of PTEN. In contrast, cotreatment of GH with the Notch signaling inhibitor, DAPT, prevented its neuroprotective effect against KA. We identified binding sites in Notch1 and Notch2 genes for STAT5. Also, GH prevented Müller cell transdifferentiation and downregulated Sox2, FGF2, and PCNA after cotreatment with KA. Additionally, GH modified TNF receptors immunoreactivity suggesting anti-inflammatory actions.

Conclusions

Our data indicate that the neuroprotective effects of GH against KA injury in the retina are mediated through the regulation of Notch signaling. Additionally, anti-inflammatory and antiproliferative effects were observed.

LNCRNA CDKN2B-AS1 regulates mesangial cell proliferation and extracellular matrix accumulation via miR-424-5p/HMGA2 axis

BACKGROUND

Previous study has demonstrated that long noncoding RNA cyclin-dependent kinase inhibitor 2B antisense RNA 1 (CDKN2B-AS1) was abnormally expressed in diabetic nephropathy (DN). However, the underlying mechanism that allows CDKN2B-AS1 in the progression of DN remains to be further elucidated.

METHODS

Peripheral blood cells of 24 diabetes patients with DN and 20 without DN were collected. Human glomerular mesangial cells (HGMC) were cultured in high glucose or low glucose medium. The expression levels of CDKN2B-AS1, microRNA (miR)-424-5p and high mobility group AT hook 2 (HMGA2) were detected by quantitative real-time polymerase chain reaction or western blot. The target association between miR-424-5p and CDKN2B-AS1 or HMGA2 was confirmed by dual-luciferase reporter and RNA immunoprecipitation assays. Cell proliferation, extracellular matrix (ECM) accumulation and phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signaling were investigated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) and western blot, respectively.

RESULTS

CDKN2B-AS1 expression was up-regulated and miR-424-5p level was down-regulated in peripheral blood of DN patients and high glucose-treated HGMC cells. CDKN2B-AS1 was validated as a sponge of miR-424-5p. Silence of CDKN2B-AS1 repressed proliferation and ECM accumulation by increasing miR-424-5p. HMGA2 was a target of miR-424-5p and miR-424-5p overexpression inhibited proliferation, ECM accumulation and PI3K/AKT pathway by targeting HMGA2. Moreover, knockdown of CDKN2B-AS1 inhibited HMGA2 expression and PI3K/AKT pathway by increasing miR-424-5p.

CONCLUSION

Knockdown of CDKN2B-AS1 suppressed proliferation, ECM accumulation and PI3K/AKT signaling by increasing miR-424-5p and decreasing HMGA2 in high glucose-treated HMGC cells.

Expression of Human PTEN-L in a Yeast Heterologous Model Unveils Specific N-Terminal Motifs Controlling PTEN-L Subcellular Localization and Function

The tumour suppressor PTEN is frequently downregulated, mutated or lost in several types of tumours and congenital disorders including PHTS (PTEN Hamartoma Tumour Syndrome) and ASD (Autism Spectrum Disorder). PTEN is a lipid phosphatase whose activity over the lipid messenger PIP₃ counteracts the stimulation of the oncogenic phosphatidylinositol 3-kinase (PI3K) pathway. Recently, several extended versions of PTEN produced in the cell by alternative translation initiation have been described, among which, PTEN-L and PTEN-M represent the longest isoforms. We previously developed a humanized yeast model in which the expression of PI3K in Saccharomyces cerevisiae led to growth inhibition that could be suppressed by co-expression of PTEN. Here, we show that the expression of PTEN-L and PTEN-M in yeast results in robust counteracting of PI3K-dependent growth inhibition. N-terminally tagged GFP-PTEN-L was sharply localized at the yeast plasma membrane. Point mutations of a putative membrane-binding helix located at the PTEN-L extension or its deletion shifted localization to nuclear. Also, a shift from plasma membrane to nucleus was observed in mutants at basic amino acid clusters at the PIP₂-binding motif, and at the Cα2 and CBR3 loops at the C2 domain. In contrast, C-terminally tagged PTEN-L-GFP displayed mitochondrial localization in yeast, which was shifted to plasma membrane by removing the first 22 PTEN-L residues. Our results suggest an important role of the N-terminal extension of alternative PTEN isoforms on their spatial and functional regulation.

An update on PTEN modulators - a patent review

Introduction: A multitude of cellular and physiological functions have been attributed to the biological activity of PTEN (Phosphatase and tensin homolog) such as inhibiting angiogenesis, promoting apoptosis, preventing cell proliferation, and maintaining cellular homeostasis. Based on whether cell growth is needed to be initiated or to be inhibited, enhancing PTEN expression or seeking to inhibit it was pursued. Areas covered: Here the authors provide recent updates to their previous publication on 'PTEN modulators: A patent review', and discuss on new specificities that affirm the therapeutic potential of PTEN in promoting neuro-regeneration, stem cell regeneration, autophagy, bone and cartilage regeneration. Also, targeting PTEN appears to be effective in developing new treatment strategies for Parkinson's disease, Alzheimer's disease, macular degeneration, immune disorders, asthma, arthritis, lupus, Crohn's disease, and several cancer types. Expert opinion: PTEN mainly inhibits the PI3k/Akt pathway. However, the PI3k/Akt pathway can be activated by other signaling proteins. Thus, novel treatment strategies that can regulate PTEN alone, or combinational treatment approaches that can induce PTEN and simultaneously affect downstream mediators in the PI3K/Akt pathway, are needed, which were not investigated in detail. Commercial interests associated with molecules that regulate PTEN are discussed here, along with limitations and new possibilities to improve them.

MicroRNA‑4712‑5p promotes proliferation of the vulvar squamous cell carcinoma cell line A431 by targeting PTEN through the AKT/cyclin D1 signaling pathways

The aim of the present study was to screen differentially expressed miRNAs in vulvar squamous cell carcinoma (VSCC), observe the role of microRNA-4712-5p in VSCC and investigate its targets and regulatory mechanism. Differentially expressed miRNAs in human VSCC tissues were screened. microRNA-4712-5p was selected and its expression level was verified in clinical tissue samples and the VSCC cell line A431 by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analysis. The overexpression vector of microRNA-4712-5p was prepared and transfected into A431 cells; subsequently, cell invasion and metastasis were examined by Cell Counting Kit-8 and Transwell migration assays. Furthermore, the target gene of miRNA-4712-5p was predicted by bioinformatics and verified by The Dual-Luciferase^® Reporter (DLR™) Assay System. The expression of phosphatase and tensin homologue (PTEN) and its downstream proteins, such as protein kinase B (PKB; AKT), glycogen synthase kinase (GSK)3β and cyclin D1, were detected by western blot assays. The expression level of microRNA-4712-5p in VSCC tissues and the A431 cell line was found to be significantly increased, promoting proliferation and invasion of VSCC. The DLR™ assay indicated that PTEN was a target of miR-4712-5p. RT-qPCR revealed that PTEN expression was markedly lower in VSCC tissues compared with that in adjacent tissues. After A431 cells were transfected with the miRNA-4712-5p overexpression vector, phospho-AKT (p-AKT) and cyclin D1 expression were notably increased, but miRNA-4712-5p-targeted PTEN and phospho-GSK3β (p-GSK3β) protein markedly decreased. Therefore, microRNA-4712-5p can reduce the expression of PTEN, further affecting its downstream p-AKT, p-GSK3β and cyclin D1 signaling pathways, promoting the proliferation and invasion of VSCC.

Modifying PTEN recruitment promotes neuron survival, regeneration, and functional recovery after CNS injury

Phosphatase and tensin homolog (PTEN) regulates apoptosis and axonal growth in the developing and adult central nervous system (CNS). Here, we show that human PTEN C-terminal PDZ interactions play a critical role in neuronal apoptosis and axon regeneration after traumatic CNS injury and stroke, highlighted by the findings that antagonizing the PDZ-motif interactions of PTEN has therapeutic applicability for these indications. Interestingly, the death-inducing function of PTEN following ischemic insult depends on a PDZ-domain interaction with MAGI-2 and MAST205, PDZ proteins that are known to recruit PTEN to the plasma membrane and stabilize its interaction with PIP3. Treatments with a human peptide that prevents PTEN association with MAGI-2 or MAST205 increased neuronal survival in multiple stroke models, in vitro. A pro-survival effect was also observed in models of retinal ischemia, optic nerve transection, and after middle cerebral artery occlusion (MCAO) in adult rats. The human PTEN peptide also improved axonal regeneration in the crushed optic nerve. Furthermore, human PTEN peptide therapy promoted functional improvement after MCAO or retinal ischemia induced via ophthalmic artery ligation. These findings show that the human peptide-based targeting of C-terminal PTEN PDZ interactions has therapeutic potential for insults of the CNS, including trauma and stroke.

Emerging Biomarkers, Tools, and Treatments for Diabetic Polyneuropathy

Diabetic neuropathy, with its major clinical sequels, notably neuropathic pain, foot ulcers, and autonomic dysfunction, is associated with substantial morbidity, increased risk of mortality, and reduced quality of life. Despite its major clinical impact, diabetic neuropathy remains underdiagnosed and undertreated. Moreover, the evidence supporting a benefit for causal treatment is weak at least in patients with type 2 diabetes, and current pharmacotherapy is largely limited to symptomatic treatment options. Thus, a better understanding of the underlying pathophysiology is mandatory for translation into new diagnostic and treatment approaches. Improved knowledge about pathogenic pathways implicated in the development of diabetic neuropathy could lead to novel diagnostic techniques that have the potential of improving the early detection of neuropathy in diabetes and prediabetes to eventually embark on new treatment strategies. In this review, we first provide an overview on the current clinical aspects and illustrate the pathogenetic concepts of (pre)diabetic neuropathy. We then describe the biomarkers emerging from these concepts and novel diagnostic tools and appraise their utility in the early detection and prediction of predominantly distal sensorimotor polyneuropathy. Finally, we discuss the evidence for and limitations of the current and novel therapy options with particular emphasis on lifestyle modification and pathogenesis-derived treatment approaches. Altogether, recent years have brought forth a multitude of emerging biomarkers reflecting different pathogenic pathways such as oxidative stress and inflammation and diagnostic tools for an early detection and prediction of (pre)diabetic neuropathy. Ultimately, these insights should culminate in improving our therapeutic armamentarium against this common and debilitating or even life-threatening condition.

miR-148a-3p exhaustion inhibits necrosis by regulating PTEN in acute pancreatitis

BACKGROUND

Acute pancreatitis (AP) is a necro-inflammatory disorder with high mortality rate. With advances in understanding the pathogenesis of AP, microRNAs (miRNAs) have been reported to play an essential role in AP progression. However, the mechanism that allows miR-148a-3p to regulate necrosis in AP remains unclear.

METHODS

Caerulein treatment was used to induce AP in mice or cells. miR-148a-3p-/- mice or miR-148a-3p inhibition in wild type mice were used to investigate the effect of miR-148a-3p on AP. The expression of miR-148a-3p was detected by quantitative real-time polymerase chain reaction (qRT-PCR). The abundances of phosphatase and tensin homolog (PTEN) and hallmarks of necrosis or apoptosis were measured by qRT-PCR or western blots (WB). Cell necrosis, apoptosis, serum amylase or lipase activity and inflammatory cytokines levels were investigated by commercial assay kit. Inflammatory infiltration was analyzed by immunohistochemistry (IHC). The interaction between miR-148a-3p and PTEN was probed by luciferase activity.

RESULTS

miR-148a-3p was highly expressed in AP and knockout of miR-148a-3p inhibited water content, cell necrosis, amylase and lipase activity while inducing PTEN expression. Moreover, miR-148a-3p deletion attenuated inflammatory infiltration and necrosis by promoting apoptosis. In addition, miR-148a-3p knockdown protected against cell necrosis, amylase, and lipase activity in AP. Intriguingly, PTEN was a target of miR-148a-3p and interference of PTEN reversed the effect of miR-148a-3p deficiency on AP in vitro.

CONCLUSION

miR-148a-3p inhibition repressed necrosis by regulating PTEN expression in AP, providing a novel biomarker of therapeutics for AP treatment.

The Akt pathway in oncology therapy and beyond (Review)

Protein kinase B (Akt), similar to many other protein kinases, is at the crossroads of cell death and survival, playing a pivotal role in multiple interconnected cell signaling mechanisms implicated in cell metabolism, growth and division, apoptosis suppression and angiogenesis. Akt protein kinase displays important metabolic effects, among which are glucose uptake in muscle and fat cells or the suppression of neuronal cell death. Disruptions in the Akt-regulated pathways are associated with cancer, diabetes, cardiovascular and neurological diseases. The regulation of the Akt signaling pathway renders Akt a valuable therapeutic target. The discovery process of Akt inhibitors using various strategies has led to the identification of inhibitors with great selectivity, low side-effects and toxicity. The usefulness of Akt emerges beyond cancer therapy and extends to other major diseases, such as diabetes, heart diseases, or neurodegeneration. This review presents key features of Akt structure and functions, and presents the progress of Akt inhibitors in regards to drug development, and their preclinical and clinical activity in regards to therapeutic efficacy and safety for patients.