lncRNA cytoskeleton regulator reduces non­small cell lung cancer radiosensitivity by downregulating miRNA­206 and activating prothymosin α.

The present study aimed to explore the role of the long noncoding RNA cytoskeleton regulator (CYTOR) in non­small cell lung cancer (NSCLC) radiosensitivity by manipulating the microRNA (miR)­206/prothymosin α (PTMA) axis. First, 58 pairs of NSCLC and paracancerous tissues, normal human lung epithelial cells and NSCLC cells were collected to analyze CYTOR expression and the relationship between CYTOR and NSCLC prognosis. Subsequently, CYTOR expression in radioresistant cells was assessed. Radioresistant cells with low CYTOR expression and parental cells with high CYTOR expression were established. Functional assays were then performed to assess changes in cell radiosensitivity after irradiation treatment. Subsequently, the downstream mechanism of CYTOR was explored. The binding interactions between CYTOR and miR­206 and between miR­206 and PTMA were predicted and certified. Xenograft transplantation was applied to confirm the role of CYTOR in the radiosensitivity of NSCLC. CYTOR was overexpressed in NSCLC and was associated with poor prognosis. CYTOR was further upregulated in NSCLC cells with radioresistance. CYTOR knockdown enhanced the radiosensitivity of NSCLC cells, while overexpression of CYTOR led to the opposite result. Mechanistically, CYTOR specifically bound to miR­206 and silencing CYTOR promoted miR­206 to enhance the radiosensitivity of NSCLC cells. PTMA is a target of miR­206 and silencing CYTOR inhibited PTMA expression via miR­206, thus promoting radiosensitivity of NSCLC cells. CYTOR knockdown also enhanced NSCLC cell radiosensitivity in vivo. CYTOR was highly expressed in NSCLC, while silencing CYTOR potentiated NSCLC cell radiosensitivity by upregulating miR­206 and suppressing PTMA. The present study preliminarily revealed the role of CYTOR in radiotherapy sensitivity of NSCLC and provided a novel potential target for the clinical treatment of NSCLC.

Thymosin ß4 increases cardiac cell proliferation, cell engraftment, and the reparative potency of human induced-pluripotent stem cell-derived cardiomyocytes in a porcine model of acute myocardial infarction.

Rationale: Previous studies have shown that human embryonic stem cell-derived cardiomyocytes improved myocardial recovery when administered to infarcted pig and non-human primate hearts. However, the engraftment of intramyocardially delivered cells is poor and the effectiveness of clinically relevant doses of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) in large animal models of myocardial injury remains unknown. Here, we determined whether thymosin ß4 (Tb4) could improve the engraftment and reparative potency of transplanted hiPSC-CMs in a porcine model of myocardial infarction (MI). Methods: Tb4 was delivered from injected gelatin microspheres, which extended the duration of Tb4 administration for up to two weeks in vitro. After MI induction, pigs were randomly distributed into 4 treatment groups: the MI Group was injected with basal medium; the Tb4 Group received gelatin microspheres carrying Tb4; the CM Group was treated with 1.2 × 108 hiPSC-CMs; and the Tb4+CM Group received both the Tb4 microspheres and hiPSC-CMs. Myocardial recovery was assessed by cardiac magnetic resonance imaging (MRI), arrhythmogenesis was monitored with implanted loop recorders, and tumorigenesis was evaluated via whole-body MRI. Results: In vitro, 600 ng/mL of Tb4 protected cultured hiPSC-CMs from hypoxic damage by upregulating AKT activity and BcL-XL and promoted hiPSC-CM and hiPSC-EC proliferation. In infarcted pig hearts, hiPSC-CM transplantation alone had a minimal effect on myocardial recovery, but co-treatment with Tb4 significantly enhanced hiPSC-CM engraftment, induced vasculogenesis and the proliferation of cardiomyocytes and endothelial cells, improved left ventricular systolic function, and reduced infarct size. hiPSC-CM implantation did not increase incidence of ventricular arrhythmia and did not induce tumorigenesis in the immunosuppressed pigs. Conclusions: Co-treatment with Tb4-microspheres and hiPSC-CMs was safe and enhanced the reparative potency of hiPSC-CMs for myocardial repair in a large-animal model of MI.

PTEN/AKT upregulation of TMSB10 contributes to lung cancer cell growth and predicts poor survival of the patients.

PTEN/AKT signaling cascade is frequently activated in various cancers, including lung cancer. The downstream effector of this signaling cascade is poorly understood. ß-Thymosin 10 (TMSB10) functions as an oncogene or tumor suppressors in cancers, whereas its significance in lung cancer remains unknown. In this study, we showed that the activation of PTEN/AKT signaling promoted the expression of TMSB10. Based on the TCGA database, TMSB10 was upregulated in lung cancer tissues and its overexpression was correlated with poor prognosis of lung cancer patients. Functional experiments demonstrated that TMSB10 knockdown suppressed, while its overexpression promoted the proliferation, growth, and migration of lung cancer cells. Apoptosis and epithelial-mesenchymal transition were also regulated by TMSB10. We therefore suggest that TMSB10 is a novel oncogene for lung cancer. Targeting TMSB10 may benefit lung cancer patients with activated PTEN/AKT signaling.

Progress on the Function and Application of Thymosin ß4.

Thymosin ß4 (Tß4) is a multifunctional and widely distributed peptide that plays a pivotal role in several physiological and pathological processes in the body, namely, increasing angiogenesis and proliferation and inhibiting apoptosis and inflammation. Moreover, Tß4 is effectively utilized for several indications in animal experiments or clinical trials, such as myocardial infarction and myocardial ischemia-reperfusion injury, xerophthalmia, liver and renal fibrosis, ulcerative colitis and colon cancer, and skin trauma. Recent studies have reported the potential application of Tß4 and its underlying mechanisms. The present study reveals the progress regarding functions and applications of Tß4.

Brain is an endocrine organ through secretion and nuclear transfer of parathymosin.

This study reports that parathymosin (PTMS) is secreted by hypothalamic stem/progenitor cells (htNSC) to inhibit senescence of recipient cells such as fibroblasts. Upon release, PTMS is rapidly transferred into the nuclei of various cell types, including neuronal GT1-7 cells and different peripheral cells, and it is effectively transferred into neuronal nuclei in various brain regions in vivo. Notably, brain neurons also produce and release PTMS, and because neuronal populations are large, they are important for maintaining PTMS in the cerebrospinal fluid which is further transferable into the blood. Compared with several other brain regions, the hypothalamus is stronger for long-distance PTMS transfer, supporting a key hypothalamic role in this function. In physiology, aging is associated with declines in PTMS production and transfer in the brain, and ptms knockdown in the hypothalamus versus hippocampus were studied showing different contributions to neurobehavioral physiology. In conclusion, the brain is an endocrine organ through secretion and nuclear transfer of PTMS, and the hypothalamus-brain orchestration of this function is protective in physiology and counteractive against aging-related disorders.

Thymosin α1 protects from CTLA-4 intestinal immunopathology.

The advent of immune checkpoint inhibitors has represented a major boost in cancer therapy, but safety concerns are increasingly being recognized. Indeed, although beneficial at the tumor site, unlocking a safeguard mechanism of the immune response may trigger autoimmune-like effects at the periphery, thus making the safety of immune checkpoint inhibitors a research priority. Herein, we demonstrate that thymosin α1 (Tα1), an endogenous peptide with immunomodulatory activities, can protect mice from intestinal toxicity in a murine model of immune checkpoint inhibitor-induced colitis. Specifically, Tα1 efficiently prevented immune adverse pathology in the gut by promoting the indoleamine 2,3-dioxygenase (IDO) 1-dependent tolerogenic immune pathway. Notably, Tα1 did not induce IDO1 in the tumor microenvironment, but rather modulated the infiltration of T-cell subsets by inverting the ratio between CD8+ and Treg cells, an effect that may depend on Tα1 ability to regulate the differentiation and chemokine expression profile of DCs. Thus, through distinct mechanisms that are contingent upon the context, Tα1 represents a plausible candidate to improve the safety/efficacy profile of immune checkpoint inhibitors.

In Vitro Immunodetection of Prothymosin Alpha in Normal and Pathological Conditions.

Prothymosin alpha (ProTα) is a highly acidic polypeptide, ubiquitously expressed in almost all mammalian cells and tissues and consisting of 109 amino acids in humans. ProTα is known to act both, intracellularly, as an anti-apoptotic and proliferation mediator, and extracellularly, as a biologic response modifier mediating immune responses similar to molecules termed as "alarmins". Antibodies and immunochemical techniques for ProTα have played a leading role in the investigation of the biological role of ProTα, several aspects of which still remain unknown and contributed to unraveling the diagnostic and therapeutic potential of the polypeptide. This review deals with the so far reported antibodies along with the related immunodetection methodology for ProTα (immunoassays as well as immunohistochemical, immunocytological, immunoblotting, and immunoprecipitation techniques) and its application to biological samples of interest (tissue extracts and sections, cells, cell lysates and cell culture supernatants, body fluids), in health and disease states. In this context, literature information is critically discussed, and some concluding remarks are presented.

Thymosin ß4: potential to treat epidermolysis bullosa and other severe dermal injuries.

Thymosin ß4 is a naturally-occurring regenerative protein present in almost all cells and body fluids, including wound fluid. In multiple preclinical injury models, it promotes dermal repair and tissue regeneration. Thymosin ß4 acts by increasing keratinocyte/epithelial cell migration, angiogenesis, and cell survival, and by decreasing inflammation, apoptosis, and scarring. It also modulates cytokines, including those that cause itching. Thymosin ß4 promotes faster repair in various chronic human wounds, including pressure ulcers, stasis ulcers, and epidermolysis bullosa lesions. The faster healing time with increased keratinocyte migration and angiogenesis and reduction in both inflammation and scarring are especially important for epidermolysis bullosa patients who suffer from slow healing and inflammation that leads to itching, infections, pain, fluid loss, scarring, and tissue damage. These multiple mechanisms of action support thymosin ß4's role in accelerating dermal repair and suggest the potential to treat various types of severe wounds, including epidermolysis bullosa patients who suffer from frequent blistering wounds that can be life threatening. There is an urgent need at this time to develop a therapeutic, such as thymosin ß4, for epidermolysis bullosa. Despite progress in gene/stem cell therapy, there is no cure for this disease and careful wound management is the standard of care.

Prothymosin α promotes STAT3 acetylation to induce cystogenesis in Pkd1-deficient mice.

Polycystic kidney disease (PKD) is characterized by the expansion of fluid-filled cysts in the kidney, which impair the function of kidney and eventually leads to end-stage renal failure. It has been previously demonstrated that transgenic overexpression of prothymosin α (ProT) induces the development of PKD; however, the underlying mechanisms remain unclear. In this study, we used a mouse PKD model that sustains kidney-specific low-expression of Pkd1 to illustrate that aberrant up-regulation of ProT occurs in cyst-lining epithelial cells, and we further developed an in vitro cystogenesis model to demonstrate that the suppression of ProT is sufficient to reduce cyst formation. Next, we found that the expression of ProT was accompanied with prominent augmentation of protein acetylation in PKD, which results in the activation of downstream signal transducer and activator of transcription (STAT) 3. The pathologic role of STAT3 in PKD has been previously reported. We determined that this molecular mechanism of protein acetylation is involved with the interaction between ProT and STAT3; consequently, it causes the deprivation of histone deacetylase 3 from the indicated protein. Conclusively, these results elucidate the significant role of ProT, including protein acetylation and STAT3 activation in PKD, which represent potential for ameliorating the disease progression of PKD.-Chen, Y.-C., Su, Y.-C., Shieh, G.-S., Su, B.-H., Su, W.-C., Huang, P.-H., Jiang, S.-T., Shiau, A.-L., Wu, C.-L. Prothymosin α promotes STAT3 acetylation to induce cystogenesis in Pkd1-deficient mice.

The role of Thymosin ß4 in angiotensin II-induced cardiomyocytes growth.

INTRODUCTION: Thymosin beta-4 (Tß4) is an actin sequestering protein and is furthermore involved in diverse biological processes including cell proliferation, differentiation, wound healing, stem- or progenitor cell differentiation, and modulates inflammatory mediators. Tß4 also attenuates fibrosis. However, the role of Tß4 in cardiomyocytes hypertrophy is unknown. AREAS COVERED: In this review, we will discuss the role of Tß4 in cardiac remodeling that specifically includes cardiac hypertrophy and fibrosis only. Our review will further cover a new signaling pathway, the wingless and integrated-1 (Wnt) pathway in cardiac remodeling. In rat neonatal and adult cardiomyocytes stimulated with angiotensin II (Ang II), we showed that Tß4 has the ability to reduce cell sizes, attenuate hypertrophy marker genes expression, along with a panel of WNT-associated gene expressions induced by Ang II. Selected target gene WNT1-inducible-signaling pathway protein 1 (WISP-1) was identified by Tß4. Data further confirmed that WISP-1 overexpression promoted cardiomyocytes growth and was reversed by Tß4 pretreatment. EXPERT OPINION: Our data suggested that Tß4 protects cardiomyocytes from hypertrophic response by targeting WISP-1. The new role of Tß4 in cardiac hypertrophy advances our understanding, and the mechanism of action of Tß4 may provide a solid foundation for the treatment of cardiac disease.

Thymosin ß4 and the vasculature: multiple roles in development, repair and protection against disease.

INTRODUCTION: Formation of the vasculature is a complex process, defects in which can lead to embryonic lethality or disease in later life. Understanding mechanisms of vasculogenesis may facilitate the treatment of developmental defects and may be extrapolated to promote wound healing and tissue repair. Thymosin ß4 (Tß4) is an actin monomer binding protein with recognized roles in vascular development, neovascularization and protection against disease. AREAS COVERED: Vascular network assembly is complex, regulated by multiple signals and cell types; Tß4 functions in many of the underlying processes, including vasculogenesis, angiogenesis, arteriogenesis, endothelial-mesenchymal transition and extracellular matrix remodeling. Loss of Tß4 perturbs vessel growth and stability, whereas exogenous application enhances capillary formation and pericyte recruitment, during development and in injury models. EXPERT OPINION: Although vascular functions for Tß4 have been well documented, the underlying molecular mechanisms remain obscure. While Tß4-induced cytoskeletal remodeling likely mediates the directional migration of endothelial cells, paracrine roles have also been implicated in migration and differentiation of smooth muscle cells. Moreover, nuclear functions of Tß4 have been described but remain to be explored in the vasculature. Delineati+ng the molecular pathways impacted by Tß4 to promote vascular growth and remodeling may reveal novel targets for prevention and treatment of vascular disease.

Thymosin beta 4 and the eye: the journey from bench to bedside.

INTRODUCTION: Thymosin beta 4 (Tß4) has important applications in ocular repair and Phase 3 clinical trials using Tß4 to treat dry eye and neurotrophic keratopathy are currently ongoing. These exciting clinical possibilities for Tß4 in the eye are the result of seminal basic scientific discoveries and contributions from so many talented investigators. Areas covered: My personal Tß4 journey began at the NIH in 1998 and propelled my career as a clinician scientist. As a tribute to the amazing individuals who have guided and supported me along with my brilliant colleagues and students who have contributed and collaborated with me over the years, this review will tell the cumulative story of how Tß4 became a major potential new therapy for corneal wound healing disorders. The journey has been marked by the thrilling exhilaration from fundamental breakthroughs in the laboratory and clinic, combined with the challenging and often harsh realities of submitting grants and obtaining funding. Expert opinion: The electrifying possibility of Tß4 as a revolutionary novel dry eye therapy is something that could have only been dreamed about just a few years ago. We believe that Tß4 eyedrops will help many patients suffering from several ocular surface related disorders.

Thymosin ß4-mediated protective effects in the heart.

INTRODUCTION: Despite recent advances in the treatment of coronary heart disease, a significant number of patients progressively develop heart failure. Reduction of infarct size after acute myocardial infarction and normalization of microvasculature in chronic myocardial ischemia could enhance cardiac survival. AREAS COVERED: Induction of neovascularization using vascular growth factors has emerged as a promising novel approach for cardiac regeneration. Thymosin ß4 (Tß4) might be a promising candidate for the treatment of ischemic heart disease. It has been characterized as a major G-actin-sequestering factor regulating cell motility, migration, and differentiation. During cardiac development, Thymosin ß4 seems essential for vascularization of the myocardium. In the adult organism, Thymosin ß4 has anti-inflammatory properties, increases myocyte and endothelial cell survival accompanied by differentiation of epicardial progenitor cells. In chronic myocardial ischemia, Tß4 overexpression enhances micro- and macrovasculature in the ischemic area and thereby improves myocardial function. A comparable effect is seen in diabetic and dyslipidemic pig ischemic hearts, suggesting an attractive therapeutic potential of adeno-associated virus encoding for Tß4 for patients with ischemic heart disease. EXPERT OPINION: Induction of mature micro-vessels is a prerequisite for chronic myocardial ischemia and might be achieved via a long-term overexpression of Thymosin ß4.

Thymosin-ß4: A key modifier of renal disease.

INTRODUCTION: There is an urgent need for new treatments for chronic kidney disease (CKD). Thymosin-ß4 is a peptide that reduces inflammation and fibrosis and has the potential to restore endothelial and epithelial cell injury, biological processes involved in the pathophysiology of CKD. Therefore, thymosin-ß4 could be a novel therapeutic direction for CKD. AREAS COVERED: Here, we review the current evidence on the actions of thymosin-ß4 in the kidney in health and disease. Using transgenic mice, two recent studies have demonstrated that endogenous thymosin-ß4 is dispensable for healthy kidneys. In contrast, lack of endogenous thymosin-ß4 exacerbates mouse models of glomerular disease and angiotensin-II-induced renal injury. Administration of exogenous thymosin-ß4, or its metabolite, Ac-SDKP, has shown therapeutic benefits in a range of experimental models of kidney disease. EXPERT OPINION: The studies conducted so far reveal a protective role for thymosin-ß4 in the kidney and have shown promising results for the therapeutic potential of exogenous thymosin-ß4 in CKD. Further studies should explore the mechanisms by which thymosin-ß4 modulates kidney function in different types of CKD. Ac-SDKP treatment has beneficial effects in many experimental models of kidney disease, thus supporting its potential use as a new treatment strategy.

Thymosin beta 4 regulation of actin in sepsis.

INTRODUCTION: Sepsis is the dysregulated host response to an infection resulting in life-threatening organ damage. Thymosin Beta 4 is an actin binding protein that inhibits the polymerization of G-actin into F-actin and improves mortality when administered intravenously to septic rats. Thymosin Beta 4 decreases inflammatory mediators, lowers reactive oxygen species, up-regulates anti-oxidative enzymes, anti-inflammatory genes, and anti-apoptotic enzymes making it an interesting protein to study in sepsis. AREAS COVERED: The authors summarize the current knowledge of actin and Thymosin Beta 4 as it relates to sepsis via a comprehensive literature search. EXPERT OPINION: Sepsis results in measurable levels of F-actin in the circulation as well as a decreased concentration of Thymosin Beta 4. It is speculated that F-actinemia contributes to microcirculatory perturbations present in patients with sepsis by disturbing laminar flow. Given that Thymosin Beta 4 inhibits the polymerization of F-actin, it is possible that Thymosin Beta 4 decreases mortality in sepsis via the regulation of actin as well as its other anti-inflammatory properties and should be further pursued as a clinical trial in humans with sepsis.

Intrinsic, Functional, and Structural Properties of ß-Thymosins and ß-Thymosin/WH2 Domains in the Regulation and Coordination of Actin Self-Assembly Dynamics and Cytoskeleton Remodeling.

ß-Thymosins are a family of heat-stable multifunctional polypeptides that are expressed as small proteins of about 5kDa (~45 amino acids) almost exclusively in multicellular animals. They were first isolated from the thymus. As full-length or truncated polypeptides, they appear to stimulate a broad range of extracellular activities in various signaling pathways, including tissue repair and regeneration, inflammation, cell migration, and immune defense. However, their cell surface receptors and structural mechanisms of regulations in these multiple pathways remain still poorly understood. Besides their extracellular activities, they belong to a larger family of small, intrinsically disordered actin-binding domains called WH2/ß-thymosin domains that have been identified in more than 1800 multidomain proteins found in different taxonomic domains of life and involved in various actin-based motile processes including cell morphogenesis, motility, adhesions, tissue development, intracellular trafficking, or pathogen infections. This review briefly surveys the main recent findings to understand how these small, intrinsically disordered but functional domains can interact with many unrelated partners and can thus integrate and coordinate various intracellular activities in actin self-assembly dynamics and cell signaling pathways linked to their cytoskeleton remodeling.

Phosphorylation of Prothymosin α. An Approach to Its Biological Significance.

Prothymosin α (ProTα), the precursor of the thymosin α1 and thymosin α11, is a 109-111 amino acids protein widely distributed in the mammalian tissues that is essential for the cell proliferation and survival through its implication on chromatin remodeling and in the proapoptotic activity. ProTα is phosphorylated at Thr residues by the M2 isoenzyme of the pyruvate kinase in a process that is dependent on the cell proliferation activity, which constitutes a novel dual functionality of this enzyme. The Thr residues phosphorylated are apparently dependent on the carcinogenic transformation of the cells. Thus, in normal lymphocytes residues Thr11 or Thr12 are phosphorylated in addition to a Thr7 residue, while in tumor cells Thr7 is the only residue phosphorylated. Phosphorylation of ProTα seems to be related to its antiapoptotic activity, although other possibilities cannot be discarded.

Thymosin Beta 4 Is a Potential Regulator of Hepatic Stellate Cells.

Liver fibrosis, a major characteristic of chronic liver disease, is inappropriate tissue remodeling caused by prolonged parenchymal cell injury and inflammation. During liver injury, hepatic stellate cells (HSCs) undergo transdifferentiation from quiescent HSCs into activated HSCs, which promote the deposition of extracellular matrix proteins, leading to liver fibrosis. Thymosin beta 4 (Tß4), a major actin-sequestering protein, is the most abundant member of the highly conserved ß-thymosin family and controls cell morphogenesis and motility by regulating the dynamics of the actin cytoskeleton. Tß4 is known to be involved in various cellular responses, including antiinflammation, wound healing, angiogenesis, and cancer progression. Emerging evidence suggests that Tß4 is expressed in the liver; however, its biological roles are poorly understood. Herein, we introduce liver fibrogenesis and recent findings regarding the function of Tß4 in various tissues and discuss the potential role of Tß4 in liver fibrosis with a special focus on the effects of exogenous and endogenous Tß4. Recent studies have revealed that activated HSCs express Tß4 in vivo and in vitro. Treatment with the exogenous Tß4 peptide inhibits the proliferation and migration of activated HSCs and reduces liver fibrosis, indicating it has an antifibrotic action. Meanwhile, the endogenously expressed Tß4 in activated HSCs is shown to promote HSCs activation. Although the role of Tß4 has not been elucidated, it is apparent that Tß4 is associated with HSC activation. Therefore, understanding the potential roles and regulatory mechanisms of Tß4 in liver fibrosis may provide a novel treatment for patients.

Thymosin ß4: Roles in Development, Repair, and Engineering of the Cardiovascular System.

The burden of cardiovascular disease is a growing worldwide issue that demands attention. While many clinical trials are ongoing to test therapies for treating the heart after myocardial infarction (MI) and heart failure, there are few options doctors able to currently give patients to repair the heart. This eventually leads to decreased ventricular contractility and increased systemic disease, including vascular disorders that could result in stroke. Small peptides such as thymosin ß4 (Tß4) are upregulated in the cardiovascular niche during fetal development and after injuries such as MI, providing increased neovasculogenesis and paracrine signals for endogenous stem cell recruitment to aid in wound repair. New research is looking into the effects of in vivo administration of Tß4 through injections and coatings on implants, as well as its effect on cell differentiation. Results so far demonstrate Tß4 administration leads to robust increases in angiogenesis and wound healing in the heart after MI and the brain after stroke, and can differentiate adult stem cells toward the cardiac lineage for implantation to the heart to increase contractility and survival. Future work, some of which is currently in clinical trials, will demonstrate the in vivo effect of these therapies on human patients, with the goal of helping the millions of people worldwide affected by cardiovascular disease.