Small Spleen Peptides (SSPs) Shape Dendritic Cell Differentiation through Modulation of Extracellular ATP Synthesis Profile.

Restoring peripheral immune tolerance is crucial for addressing autoimmune diseases. An ancient mechanism in maintaining the balance between inflammation and tolerance is the ratio of extracellular ATP (exATP) and adenosine. Our previous research demonstrated the effectiveness of small spleen peptides (SSPs) in inhibiting psoriatic arthritis progression, even in the presence of the pro-inflammatory cytokine TNFα, by transforming dendritic cells (DCs) into tolerogenic cells and fostering regulatory Foxp3+ Treg cells. Here, we identified thymosins as the primary constituents of SSPs, but recombinant thymosin peptides were less efficient in inhibiting arthritis than SSPs. Since Tß4 is an ecto-ATPase-binding protein, we hypothesized that SSPs regulate exATP profiles. Real-time investigation of exATP levels in DCs revealed that tolerogenic stimulation led to robust de novo exATP synthesis followed by significant degradation, while immunogenic stimulation resulted in a less pronounced increase in exATP and less effective degradation. These contrasting exATP profiles were crucial in determining whether DCs entered an inflammatory or tolerogenic state, highlighting the significance of SSPs as natural regulators of peripheral immunological tolerance, with potential therapeutic benefits for autoimmune diseases. Finally, we demonstrated that the tolerogenic phenotype of SSPs is mainly influenced by adenosine receptors, and in vivo administration of SSPs inhibits psoriatic skin inflammation.

In Vitro Study of Thymosin Beta 4 Promoting Transplanted Fat Survival by Regulating Adipose-Derived Stem Cells.

BACKGROUND: Autologous fat grafting (AFG) has emerged as a highly sought-after plastic surgery procedure, although its success has been hampered by the uncertain fat survival rate. Current evidence suggests that adipose-derived stem cells (ADSCs) may contribute to fat retention in AFG. In previous studies, it was confirmed that thymosin beta 4 (Tß4) could enhance fat survival in vivo, although the precise mechanism remains unclear. METHODS: ADSCs were isolated from patients undergoing liposuction and their proliferation, apoptosis, anti-apoptosis, and migration were analyzed under Tß4 stimulation using cell counting kit-8, flow cytometry, wound healing assay, and real-time quantitative PCR. The mRNA levels of genes relating to angiogenesis and Hippo signaling were also determined. RESULTS: Tß4 at 100 ng/mL (p-value = 0.0171) and 1000 ng/mL (p-value = 0.0054) significantly increased ADSC proliferation from day 1 compared to the control group (0 ng/mL). In addition, the mRNA levels of proliferation-associated genes were elevated in the Tß4 group. Furthermore, Tß4 enhanced the anti-apoptotic ability of ADSCs when stimulated with Tß4 and an apoptotic induction reagent (0 ng/mL vs. 1000 ng/mL, p-value = 0.011). Crucially, the mRNA expression levels of angiogenesis-related genes and critical genes in the Hippo pathway were affected by Tß4 in ADSCs. CONCLUSIONS: Tß4 enhances adipose viability in AFG via facilitating ADSC proliferation and reducing apoptosis, and acts as a crucial positive regulator of ADSC-associated angiogenesis. Additionally, Tß4 could be accountable for the phenotypic adjustment of ADSCs by regulating the Hippo pathway. NO LEVEL ASSIGNED: This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Ligustilide prevents thymic immune senescence by regulating Thymosin ß15-dependent spatial distribution of thymic epithelial cells.

BACKGROUND: Thymus is the most crucial organ connecting immunity and aging. The progressive senescence of thymic epithelial cells (TECs) leads to the involution of thymus under aging, chronic stress and other factors. Ligustilide (LIG) is a major active component of the anti-aging Chinese herbal medicine Angelica sinensis (Oliv.) Diels, but its role in preventing TEC-based thymic aging remains elusive. PURPOSE: This study explored the protective role of Ligustilide in alleviating ADM (adriamycin) -induced thymic immune senescence and its underlying molecular mechanisms. METHOD: The protective effect of Ligustilide on ADM-induced thymic atrophy was examined by mouse and organotypic models, and conformed by SA-ß-gal staining in TECs. The abnormal spatial distribution of TECs in the senescent thymus was analyzed using H&E, immunofluorescence and flow cytometry. The possible mechanisms of Ligustilide in ADM-induced thymic aging were elucidated by qPCR, fluorescence labeling and Western blot. The mechanism of Ligustilide was subsequently validated through actin polymerization inhibitor, genetic engineering to regulate Thymosin ß15 (Tß15) and Tß4 expression, molecular docking and ß Thymosin-G-actin cross-linking assay. RESULTS: At a 5 mg/kg dose, Ligustilide markedly ameliorated ADM-induced weight loss and limb grip weakness in mice. It also reversed thymic damage and restored positive selection impaired by ADM. In vitro, ADM disrupted thymic structure, reduced TECs number and hindered double negative (DN) T cell differentiation. Ligustilide counteracted these effects, promoted TEC proliferation and reticular differentiation, leading to an increase in CD4+ single positive (CD4SP) T cell proportion. Mechanistically, ADM diminished the microfilament quantity in immortalized TECs (iTECs), and lowered the expression of cytoskeletal marker proteins. Molecular docking and cross-linking assay revealed that Ligustilide inhibited the protein binding between G-actin and Tß15 by inhibiting the formation of the Tß15-G-actin complex, thus enhancing the microfilament assembly capacity in TECs. CONCLUSION: This study, for the first time, reveals that Ligustilide can attenuate actin depolymerization, protects TECs from ADM-induced acute aging by inhibiting the binding of Tß15 to G-actin, thereby improving thymic immune function. Moreover, it underscores the interesting role of Ligustilide in maintaining cytoskeletal assembly and network structure of TECs, offering a novel perspective for deeper understanding of anti thymic aging.

Therapeutic applications of thymosin peptides: a patent landscape 2018-present.

INTRODUCTION: Thymosins are small proteins found mainly in the thymus. They are involved in several biological processes, including immunoregulation, angiogenesis, and anti-inflammatory activity. Due to these multiple activities, thymosins are widely used as therapeutics. In fact, these peptides have shown interesting results in the treatment of eye disorders, anticancer therapy, and dysregulated immune disorders. AREA COVERED: We analyzed the thymosins therapeutic patent landscape describing the most significant patents published after 2018 and originally written in English, classified according to the different type of functions and diseases. We searched 'Thymosin' on Patentscope and Espacenet. EXPERT OPINION: Thymalfasin (Zadaxin) is the only FDA-approved thymosine-based drug used to treat chronic hepatitis B and C and as a chemotherapy inducer. This outcome demonstrates how thymosins can be exploited as therapeutics, especially in immunological and anti-cancer therapies. However, the development of modified thymosins could expand their therapeutic interest and application in different diseases. In fact, by chemical modifications, it is possible to increase proteolytic stability in the biological environment, enhance cell permeability, and stabilize the secondary structure of the peptide. Finally, the development of shorter sequences could reduce the cost and production time of these thymosin-based drugs.

Targeted Deletion of Thymosin Beta 4 in Hepatic Stellate Cells Ameliorates Liver Fibrosis in a Transgenic Mouse Model.

Liver fibrosis is the most common feature of liver disease, and activated hepatic stellate cells (HSCs) are the main contributors to liver fibrosis. Thus, finding key targets that modulate HSC activation is important to prevent liver fibrosis. Previously, we showed that thymosin ß4 (Tß4) influenced HSC activation by interacting with the Hedgehog pathway in vitro. Herein, we generated Tß4 conditional knockout (Tß4-flox) mice to investigate in vivo functions of Tß4 in liver fibrosis. To selectively delete Tß4 in activated HSCs, double-transgenic (DTG) mice were generated by mating Tß4-flox mice with α-smooth muscle actin (α-Sma)-Cre-ERT2 mice, and these mice were administered carbon tetrachloride (CCl4) or underwent bile duct ligation to induce liver fibrosis. Tß4 was selectively suppressed in the activated HSCs of DTG mouse liver, and this reduction attenuated liver injury, including fibrosis, in both fibrotic models by repressing Hedgehog (Hh) signaling. In addition, the re-expression of Tß4 by an adeno-associated virus reversed the effect of HSC-specific Tß4 deletion and led to liver fibrosis with Hh activation in CCl4-exposed mice treated with tamoxifen. In conclusion, our results demonstrate that Tß4 is a crucial regulator of HSC activation, suggesting it as a novel therapeutic target for curing liver fibrosis.

Synergistic anti-cancer and attenuation effects of thymosin on chemotherapeutic drug vinorelbine in tumor-bearing zebrafish.

Vinorelbine, the standard chemotherapy drug on advanced lung cancer, causes adverse events such as immunosuppression and bone marrow suppression. Thus, it is necessary to find drugs that could improve immune function and synergistically enhance the anti-tumor effect of vinorelbine. Thymosin is reported to inhibit tumor growth as an immunomodulator. Herein, to study the synergistic anti-cancer and attenuation effects of thymosin on vinorelbine, human lung cancer A549 cells that were labeled with CM-DiI were transplanted into zebrafish to establish the lung cancer xenotransplanted model. After treatment of vinorelbine and different concentrations of thymosin, the fluorescence intensity of CM-DiI-labeled A549 cells and the number of apoptotic muscle cells in the tumor-bearing zebrafish were detected. Besides, effects of thymosin on vinorelbine-reduced macrophages and T cells were identified in the transgenic zebrafish (Tg:zlyz-EGFP and Tg:rag2-DsRed). Then, the qRT-PCR was used to determine the alterations of the immune-related factors at the transcription level. Thymosin showed a marked synergistic anti-cancer effect with vinorelbine for the xenograft human lung cancer A549 cells, and the synergistic effect enhanced in a dose-dependent manner. Moreover, thymosin alleviated vinorelbine-induced muscle cell apoptosis, macrophage reduction, and T cell suppression. Compared with the vinorelbine group, co-administration with thymosin raised the mRNA levels of TNF-α, TNF-ß, INF-γ, and GM-CSF. Thus, thymosin possesses synergistic anti-cancer effect on vinorelbine, and has protective effect on vinorelbine-induced immunosuppression. Thymosin, as an adjuvant immunomodulatory therapy, has great potential in enhancing the clinical application of vinorelbine.

Novel evidence of Thymosin α1 immunomodulatory properties in SARS-CoV-2 infection: Effect on innate inflammatory response in a peripheral blood mononuclear cell-based in vitro model.

The peculiar property of Thymosin alpha 1 (Tα1) to act as master regulator of immune homeostasis has been successfully defined in different physiological and pathological contexts ranging from cancer to infection. Interestingly, recent papers also demonstrated its mitigating effect on the "cytokine storm" as well as on the T-cell exhaustion/activation in SARS-CoV-2 infected individuals. Nevertheless, in spite of the increasing knowledge on Tα1-induced effects on T cell response confirming the distinctive features of this multifaceted peptide, little is known on its effects on innate immunity during SARS-CoV-2 infection. Here, we interrogated peripheral blood mononuclear cell (PBMC) cultures stimulated with SARS-CoV-2 to disclose Tα1 properties on the main cell players of early response to infection, namely monocytes and myeloid dendritic cells (mDC). Moving from ex vivo data showing an enhancement in the frequency of inflammatory monocytes and activated mDC in COVID-19 patients, a PBMC-based experimental setting reproduced in vitro a similar profile with an increased percentage of CD16+ inflammatory monocytes and mDC expressing CD86 and HLA-DR activation markers in response to SARS-CoV-2 stimulation. Interestingly, the treatment of SARS-CoV-2-stimulated PBMC with Tα1 dampened the inflammatory/activation status of both monocytes and mDC by reducing the release of pro-inflammatory mediators, including TNF-α, IL-6 and IL-8, while promoting the production of the anti-inflammatory cytokine IL-10. This study further clarifies the working hypothesis on Tα1 mitigating action on COVID-19 inflammatory condition. Moreover, these evidence shed light on inflammatory pathways and cell types involved in acute SARS-CoV-2 infection and likely targetable by newly immune-regulating therapeutic approaches.

The preliminary study of exosomes derived from thymosin beta 4-treated adipose-derived stem cells in fat grafting.

BACKGROUND: The retention rate in autologous fat grafting is an increasing concern for surgeons and patients. Our previous research verified that thymosin beta 4 (Tß4) positively affected fat survival, while the mechanism was unknown. The endothelial cells (ECs) and exosomes derived from adipose-derived stem cells (ADSCs) were regarded to play a critical role in fat transplantation. OBJECTIVE: This study aimed to evaluate the effect of exosomes derived from Tß4-treated ADSCs on EC proliferation and to identify the exosomal microRNA (miRNA) profile compared with the Tß4-untreated group. Additionally, this research intended to recognize the related molecules and signaling pathways in the Tß4-treated group with potential roles in fat transplants. METHODS: ADSCs were collected from patients who underwent liposuction surgery. Depending on whether the medium was supplemented with exogenous Tß4 or not, exosomes derived from cultured ADSCs were divided into the Tß4-Exos group and Con-Exos group. Exosome uptake and cell counting kit-8 (CCK-8) assays assessed the influence of Tß4-Exos on EC proliferation. The exosomal miRNAs of the two groups were analyzed by next-generation sequencing. With the criteria at the |log2 (fold change)| ≥ 1 and p-value < 0.05, up-regulated and down-regulated differentially expressed miRNAs (DEMs) were obtained. Prediction databases were used to predict the downstream mRNAs for DEMs. And then, overlapping genes for the up-regulated DEMs and the down-regulated were screened out, followed by enrichment analysis, protein-protein interaction network construction, and the gene cluster and hub gene identification. RESULTS: ADSCs were obtained from four female patients. The exosome uptake and CCK-8 assays showed that the Tß4-Exos could increase cell growth rate compared with the control group (DMEM-H + PBS). In Tß4-Exos and Con-Exos groups, 2651 exosomal miRNAs were recognized, with 80 up-regulated and 99 down-regulated DEMs according to the criteria. After the prediction, 621 overlapping genes for the up-regulated and 572 for the down-regulated DEMs were screened. The subsequent bioinformatics analysis found specific molecules and pathways related to the positive effect on fat survival. CONCLUSIONS: The exosomes derived from Tß4-treated ADSCs probably positively affect EC proliferation. Compared with the Con-Exos group, several exosomal DEMs, genes, and pathways were distinguished. These findings of this exploratory study provide the potential direction for future in-depth research on fat grafting.

Thymosin ß4 and Actin: Binding Modes, Biological Functions and Clinical Applications.

Thymosin ß4 (Tß4) is the ß-thymosin (Tßs) with the highest expression level in human cells; it makes up roughly 70-80% of all Tßs in the human body. Combining the mechanism and activity studies of Tß4 in recent years, we provide an overview of the subtle molecular mechanism, pharmacological action, and clinical applications of Tß4. As a G-actin isolator, Tß4 inhibits the polymerization of G-actin by binding to the matching site of G-actin in a 1:1 ratio through conformational and spatial effects. Tß4 can control the threshold concentration of G-actin in the cytoplasm, influence the balance of depolymerization and polymerization of F-actin (also called Tread Milling of F-actin), and subsequently affect cell's various physiological activities, especially motility, development and differentiation. Based on this, Tß4 is known to have a wide range of effects, including regulation of inflammation and tumor metastasis, promotion of angiogenesis, wound healing, regeneration of hair follicles, promotion of the development of the nervous system, and improving bone formation and tooth growth. Tß4 therefore has extensive medicinal applications in many fields, and serves to preserve the kidney, liver, heart, brain, intestine, and other organs, as well as hair loss, skin trauma, cornea repairing, and other conditions. In this review, we focus on the mechanism of action and clinical application of Tß4 for its main biological functions.

Immunogenic Cell Death, DAMPs and Prothymosin α as a Putative Anticancer Immune Response Biomarker.

The new and increasingly studied concept of immunogenic cell death (ICD) revealed a previously unknown perspective of the various regulated cell death (RCD) modalities, elucidating their immunogenic properties and rendering obsolete the notion that immune stimulation is solely the outcome of necrosis. A distinct characteristic of ICD is the release of danger-associated molecular patterns (DAMPs) by dying and/or dead cells. Thus, several members of the DAMP family, such as the well-characterized heat shock proteins (HSPs) HSP70 and HSP90, the high-mobility group box 1 protein and calreticulin, and the thymic polypeptide prothymosin α (proTα) and its immunoreactive fragment proTα(100-109), are being studied as potential diagnostic tools and/or possible therapeutic agents. Here, we present the basic aspects and mechanisms of both ICD and other immunogenic RCD forms; denote the role of DAMPs in ICD; and further exploit the relevance of human proTα and proTα(100-109) in ICD, highlighting their possible clinical applications. Furthermore, we present the preliminary results of our in vitro studies, which show a direct correlation between the concentration of proTα/proTα(100-109) and the levels of cancer cell apoptosis, induced by anticancer agents and γ-radiation.

TMSB10 Promotes Progression of Clear Cell Renal Cell Carcinoma via JUN Transcription Regulation.

OBJECTIVE: Thymosin b10 (TMSB10), a member of the thymosin family, is mainly located in cells and participates in the assembly and occurrence of cytoskeleton. We aimed to investigate the regulatory mechanism of TMSB10 in ccRCC. METHODS: In this study, Xiantao Academic Tools were taken to perform the pan-cancer expression and immune infiltration analysis of TMSB10. Furthermore, it is found that there is a binding site for JUN in the promoter region of TMSB10 through the JASPAR database predictive analysis. The CHIP experiment is used to confirm that JUN regulates the expression of TMSB10 through transcription, and to further detect the mRNA expression level of TMSB10 and JUN in ccRCC cell lines by qRT-PCR. Proliferation and apoptosis function analysis was also carried out to determine the functional changes of ccRCC cell lines after the expression of TMSB10 was regulated by JUN transcription. RESULTS: The results show that TMSB10 is significantly up-regulated in a variety of cancers. Moreover, JUN regulates the high expression of TMSB10 through transcription and further promotes the proliferation of ccRCC cells and inhibits their apoptosis. CONCLUSIONS: In conclusion, this study shows that JUN transcription regulates the high expression of TMSB10 and promotes the progress of ccRCC.

Thymosin ß4 Is an Endogenous Iron Chelator and Molecular Switcher of Ferroptosis.

Thymosin ß4 (Tß4) was extracted forty years agofrom calf thymus. Since then, it has been identified as a G-actin binding protein involved in blood clotting, tissue regeneration, angiogenesis, and anti-inflammatory processes. Tß4 has also been implicated in tumor metastasis and neurodegeneration. However, the precise roles and mechanism(s) of action of Tß4 in these processes remain largely unknown, with the binding of the G-actin protein being insufficient to explain these multi-actions. Here we identify for the first time the important role of Tß4 mechanism in ferroptosis, an iron-dependent form of cell death, which leads to neurodegeneration and somehow protects cancer cells against cell death. Specifically, we demonstrate four iron2+ and iron3+ binding regions along the peptide and show that the presence of Tß4 in cell growing medium inhibits erastin and glutamate-induced ferroptosis in the macrophage cell line. Moreover, Tß4 increases the expression of oxidative stress-related genes, namely BAX, hem oxygenase-1, heat shock protein 70 and thioredoxin reductase 1, which are downregulated during ferroptosis. We state the hypothesis that Tß4 is an endogenous iron chelator and take part in iron homeostasis in the ferroptosis process. We discuss the literature data of parallel involvement of Tß4 and ferroptosis in different human pathologies, mainly cancer and neurodegeneration. Our findings confronted with literature data show that controlled Tß4 release could command on/off switching of ferroptosis and may provide novel therapeutic opportunities in cancer and tissue degeneration pathologies.

Hormonal Regulation of the MHC Class I Gene in Thyroid Cells: Role of the Promoter "Tissue-Specific" Region.

In previous studies we have demonstrated that the expression of the Major Histocompatibility Complex (MHC) class I gene in thyrocytes is controlled by several hormones, growth factors, and drugs. These substances mainly act on two regions of the MHC class I promoter a "tissue-specific" region (-800 to -676 bp) and a "hormone/cytokines-sensitive" region (-500 to -68 bp). In a previous study, we have shown that the role of the "tissue-specific" region in the MHC class I gene expression is dominant compared to that of the "hormone/cytokines-sensitive" region. In the present report we further investigate the dominant role of the "tissue-specific" region evaluating the effect of thyroid stimulating hormone (TSH), methimazole (MMI), phenylmethimazole (C10), glucose and thymosin-α1. By performing experiments of electrophoretic mobility shift assays (EMSAs) we show that TSH, MMI and C10, which inhibit MHC class I expression, act on the "tissue-specific" region increasing the formation of a silencer complex. Glucose and thymosin-α1, which stimulate MHC class I expression, act decreasing the formation of this complex. We further show that the silencer complex is formed by two distinct members of the transcription factors families activator protein-1 (AP-1) and nuclear factor-kB (NF-kB), c-jun and p65, respectively. These observations are important in order to understand the regulation of MHC class I gene expression in thyroid cells and its involvement in the development of thyroid autoimmunity.

Discovery of thymosin ß4 as a human exerkine and growth factor.

Skeletal muscle is an endocrine organ secreting exercise-induced factors (exerkines), which play a pivotal role in interorgan cross talk. Using mass spectrometry (MS)-based proteomics, we characterized the secretome and identified thymosin ß4 (TMSB4X) as the most upregulated secreted protein in the media of contracting C2C12 myotubes. TMSB4X was also acutely increased in the plasma of exercising humans irrespective of the insulin resistance condition or exercise mode. Treatment of mice with TMSB4X did not ameliorate the metabolic disruptions associated with diet induced-obesity, nor did it enhance muscle regeneration in vivo. However, TMSB4X increased osteoblast proliferation and neurite outgrowth, consistent with its WADA classification as a prohibited growth factor. Therefore, we report TMSB4X as a human exerkine with a potential role in cellular cross talk.

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.

Effects of thymosin ß4-derived peptides on migration and invasion of ovarian cancer cells.

BACKGROUND: Thymosin ß4 (Tß4) is a highly conserved actin binding protein associated with the metastatic potential of tumor cells by stimulating cell migration. The role of Tß4 and its derived fragment peptides in migration of ovarian cancer cells has not been studied. OBJECTIVE: To analyze the effects of Tß4 and its derived fragment peptides on ovarian cancer cell migration and invasion, we applied Tß4 and three Tß4-derived synthetic peptides to SKOV3 ovarian cancer cells. METHOD: The migration and invasion of SKOV3 cells treated with Tß4(1-43), Tß4(1-15), Tß4(12-26), Tß4(23-), and untreated control were analyzed by in vitro migration and invasion assay with transwell plate. Cell proliferation assay was conducted to identify the effect of Tß4 and its derived peptide on SKOV3 cell proliferation. The expression of Tß4 related proteins related with cell proliferation was analyzed by Western blot after treatment with Tß4 and its derived peptides. RESULTS: Cell migration and invasion were significantly increased in Tß4 peptide-treated SKOV3 cells compared with untreated control. All three Tß4-derived fragment peptides including those without an actin binding site significantly stimulated migration and invasion of SKOV3 cells. Tß4 and its derived peptide significantly stimulated SKOV3 cell proliferation and up-regulated the expression of RACK-1 protein. CONCLUSIONS: The Tß4 peptide and all of its derived fragment peptides including those without an actin binding motif stimulate migration and invasion of SKOV3 ovarian cancer cells. All peptides significantly increased RACK-1 expression and cell proliferation of SKOV3 cells. These results suggest that Tß4 stimulates migration and invasion of SKOV3 cells by stimulation of cell proliferation through up-regulation of RACK-1 protein.

Thymosin ß4 released from functionalized self-assembling peptide activates epicardium and enhances repair of infarcted myocardium.

The epicardium plays an important role in cardiomyogenesis during development, while it becomes quiescent in adult heart during homeostasis. This study investigates the efficiency of thymosin ß4 (Tß4) release with RPRHQGVM conjugated to the C-terminus of RADA16-I (RADA-RPR), the functionalized self-assembling peptide (SAP), to activate the epicardium and repairing the infarcted myocardium. Methods: The functionalized SAP was constituted with self-assembling motif, Tß4-binding site, and cell adhesive ligand. Myocardial infarction (MI) models of the transgenic mice were established by ligation of the left anterior descending coronary artery. At one week after intramyocardial injection of Tß4-conjugated SAP, the activation of the epicardium was assessed. At four weeks after implantation, the migration and differentiation of epicardium-derived cells (EPDCs) as well as angiogenesis, lymphangiogenesis and myocardial regeneration were examined. Results: We found that the designer RADA-RPR bound Tß4 and adhered to EPDCs and that Tß4 released from the functionalized SAP could effectively activate the epicardium and induce EPDCs to differentiate towards cardiovascular cells as well as lymphatic endothelial cells. Moreover, SAP-released Tß4 (SAP-Tß4) promoted proliferation of cardiomyocytes. Furthermore, angiogenesis, lymphangiogenesis and myocardial regeneration were enhanced in the MI models at 4 weeks after delivery of SAP-Tß4 along with attenuation of adverse myocardial remodeling and significantly improved cardiac function. Conclusions: These results demonstrate that sustained release of Tß4 from the functionalized SAP can activate the epicardium and effectively enhance the repair of infarcted myocardium. We believe the delivery of SAP-Tß4 may be a promising strategy for MI therapy.

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.

Antimicrobial Effects of Thymosin Beta-4 and Ciprofloxacin Adjunctive Therapy in Pseudomonas aeruginosa Induced Keratitis.

Prior work has indicated that thymosin beta 4 (Tß4) administered with ciprofloxacin markedly improves disease outcome for Pseudomonas aeruginosa (PA)-induced keratitis. As a result, the goal of the current study was to elucidate mechanisms by which Tß4 mitigates the corneal response; specifically, regarding its bactericidal influence and potential synergy with ciprofloxacin. An in vitro approach was carried out using minimum inhibitory concentration (MIC) assays to assess bactericidal activity against PA. In addition, antimicrobial peptide (AMP) production was evaluated at the mRNA levels using human corneal epithelial cells in response to lipopolysaccharide (LPS) challenge. The results of the MIC assays did not show direct bactericidal activity with Tß4 alone, although ciprofloxacin exhibited significant killing at concentrations far lower than clinically dosed. Tß4, however, displayed an indirect effect on bacterial killing, as shown by an upregulation of AMPs and related molecules. The cumulative data from this study indicate an indirect bactericidal role of Tß4, as well as a synergistic relationship with ciprofloxacin. Furthermore, ciprofloxacin alone was found to influence cellular functions that otherwise have yet to be reported. These results highlight a mechanism of intracellular communication for Tß4 and further strengthen its development as an adjunct therapy with antibiotics for corneal infections.

Tß4 suppresses lincRNA-p21-mediated hepatic apoptosis and fibrosis by inhibiting PI3K-AKT-NF-κB pathway.

Hepatic injury is one of the most challenging diseases in clinical medicine. Hepatic injury is accompanied by hepatocyte apoptosis and leads to hepatic fibrosis and cirrhosis, which may cause liver cancer and increased mortality. Therefore, it is essential to investigate the regulation mechanism and therapeutic strategies for hepatic injury. In the study, the effects of Thymosin ß4 (Tß4) on Long intergenic noncoding RNA-p21 (lincRNA-p21)-mediated liver injury were investigated. Results showed that lincRNA-p21 overexpression promoted hepatocytes apoptosis, which was blocked by Tß4. Besides, Tß4 reversed the levels of cleaved caspase-3 and caspase-9 induced by lincRNA-p21. LincRNA-p21 overexpression also caused the pathological injury and fibrosis in hepatic tissues and increased the levels of fibrosis-related proteins (Collagen I, α-SMA and TIMP-1), and induced hydroxyproline and ALT production. However, Tß4 reversed the effects of overexpression of lincRNA-p21 on hepatic injury and fibrosis. In vitro experiments, after lincRNA-p21 was overexpressed in hepatic stellate cells (HSCs), the proliferation ability and the levels of HSCs markers α-SMA and Desmin were increased. However, Tß4 reversed the effects of lincRNA-p21 on HSCs. Furthermore, the PI3K-AKT-NF-κB pathway was activated by lincRNA-p21, which was then reversed by the Tß4 administration. After the mice treated by insulin-like growth factor-1 (IGF-1) (the activator of PI3K-AKT), the inhibitory effect of Tß4 on activated the PI3K-AKT-NF-κB pathway was abrogated. Besides, IGF-1 abolished the protective effects of Tß4 on hepatic apoptosis and fibrosis induced by lincRNA-p21. Therefore, Tß4 reversed. lincRNA-p21-mediated liver injury through inhibiting PI3K-AKT-NF-κB pathway. Tß4 may be a promising drug for fibrosis therapy.