Effect of prothymosin α on neuroplasticity following cerebral ischemia‑reperfusion injury

Prothymosin α (ProT), a highly acidic nuclear protein with multiple cellular functions, has shown potential neuroprotective properties attributed to its anti‑necrotic and anti‑apoptotic activities. The present study aimed to investigate the beneficial effect of ProT on neuroplasticity after ischemia‑reperfusion injury and elucidate its underlying mechanism of action. Primary cortical neurons were either treated with ProT or overexpressing ProT by gene transfection and exposed to oxygen‑glucose deprivation for 2 h in vitro. Immunofluorescence staining for ProT and MAP‑2 was performed to quantify ProT protein expression and assess neuronal arborization. Mice treated with vehicle or ProT (100 µg/kg) and ProT overexpression in transgenic mice received middle cerebral artery occlusion for 50 min to evaluate the effect of ProT on neuroplasticity‑associated protein following ischemia‑reperfusion injury. The results demonstrated that in cultured neurons ProT significantly increased neurite lengths and the number of branches, accompanied by an upregulation mRNA level of brain‑derived neurotrophic factor. Furthermore, ProT administration improved the protein expressions of synaptosomal‑associated protein, 25 kDa and postsynaptic density protein 95 after ischemic‑reperfusion injury in vivo. These findings suggested that ProT can potentially induce neuroplasticity effects following ischemia‑reperfusion injury.

The Clinical Relevance and Functional Implications of Thymosin Beta-10 in Glioma

Glioma is a highly aggressive form of brain cancer characterized by limited treatment options and poor patient prognosis. In this study, we aimed to elucidate the oncogenic role of thymosin beta-10 (TMSB10) in glioma through comprehensive analyses of patient data from the TCGA and GTEx databases. Our investigation encompassed several key aspects, including the analysis of patients' clinical characteristics, survival analysis, in vitro and in vivo functional experiments, and the exploration of correlations between TMSB10 expression and immune cell infiltration. Our findings revealed a significant upregulation of TMSB10 expression in glioma tissues compared to normal brain tissues, with higher expression levels observed in tumors of advanced histological grades. Moreover, we observed positive correlations between TMSB10 expression and patient age, while no significant association with gender was detected. Additionally, TMSB10 exhibited marked elevation in gliomas with wild-type IDH and noncodeletion of 1p/19q. Survival analysis indicated that high TMSB10 expression was significantly associated with worse overall survival, disease-specific survival, and progression-free survival in glioma patients. Functionally, knockdown of TMSB10 in glioma cells resulted in reduced cellular growth rates and impaired tumor growth in xenograft models. Furthermore, our study revealed intriguing correlations between TMSB10 expression and immune cell infiltration within the tumor microenvironment. Specifically, TMSB10 showed negative associations with plasmacytoid dendritic cells (pDC) and γδ T cells (Tgd), while displaying positive correlations with neutrophils and macrophages. These findings collectively provide valuable insights into the oncogenic properties of TMSB10 in glioma, suggesting its potential as a therapeutic target and a biomarker for patient stratification.

[The Thymic Hormone Thymosin-1α Reduces the Pro-Inflammatory Response of Raw 264.7 Cells Induced by Endotoxin]

The aim of this work was to study the effects of thymosin-1 alpha (Tα1) on the anti-inflammatory response of RAW 264.7 macrophages cultured in the presence of lipopolysaccharide (LPS) from the walls of gram-negative bacteria. As well, we evaluated production of pro-inflammatory cytokines and the activity of the NF-κB and SAPK/JNK signaling pathways. In addition, the level of expression of a number of genes that regulate cell apoptosis, as well as the activity of receptors involved in the pro-inflammatory response, was determined. First, the addition of Tα1 normalized the level of cytokine production to varying degrees, with a particularly noticeable effect on IL-1β and IL-6. Second, the addition of Tα1 normalized the activity of the NF-κB and SAPK/JNK signaling cascades and the expression of the Tlr4 gene. Third, Tα1 significantly reduced p53 and the activity of the P53 gene, which is a marker of cell apoptosis. Fourth, it was shown that the increase in Ar-1 gene expression under the influence of LPS was significantly reduced using Tα1. Thus, it was found that the presence of Tα1 in the RAW 264.7 cell culture medium significantly reduced the level of the pro-inflammatory response of cells.

Thymosin α1 modulated the immune landscape of COVID-19 patients revealed by single-cell RNA and TCR sequencing

BACKGROUND

The Coronavirus disease-19 (COVID-19) pandemic has posed a serious threat to global health. Thymosin α1 (Tα1) was considered to be applied in COVID-19 therapy. However, the data remains limited.

METHODS

Participants with or without Tα1 treatment were recruited. Single cell RNA-sequencing (scRNA-seq) and T cell receptor-sequencing (TCR-seq) of the peripheral blood mononuclear cell (PBMC) samples were done to analyze immune features. The differential expression analysis and functional enrichment analysis were performed to explore the mechanism of Tα1 therapy.

RESULTS

33 symptomatic SARS-CoV-2-infected individuals (COV) and 11 healthy controls (HC) were enrolled in this study. The proportion of CD3+ KLRD1+ NKT, TBX21+ CD8+ NKT was observed to increase in COVID-19 patients with Tα1 treatment (COVT) than those without Tα1 (COV) (p = 0.024; p = 0.010). These two clusters were also significantly higher in Health controls with Tα1 treatment (HCT) than those without Tα1 (HC) (p = 0.016; p = 0.031). Besides, a series of genes and pathways related to immune responses were significantly higher enriched in Tα1 groups TBX21+ CD8+ NKT, such as KLRB1, PRF1, natural killer cell-mediated cytotoxicity pathway, chemokine signaling pathway, JAK-STAT signaling pathway. The increased TRBV9-TRBJ1-1 pair existed in both HCs and COVID-19 patients after Tα1 treatment. 1389 common complementarity determining region 3 nucleotides (CDR 3 nt) were found in COV and HC, while 0 CDR 3 nt was common in COVT and HCT.

CONCLUSIONS

Tα1 increased CD3+ KLRD1+ NKT, TBX21+ CD8+ NKT cell proportion and stimulated the diversity of TCR clones in COVT and HCT. And Tα1 could regulate the expression of genes associated with NKT activation or cytotoxicity to promote NKT cells. These data support the use of Tα1 in COVID-19 patients.

Thymosin β4 and prothymosin α promote cardiac regeneration post-ischaemic injury in mice

AIMS

The adult mammalian heart is a post-mitotic organ. Even in response to necrotic injuries, where regeneration would be essential to reinstate cardiac structure and function, only a minor percentage of cardiomyocytes undergo cytokinesis. The gene programme that promotes cell division within this population of cardiomyocytes is not fully understood. In this study, we aimed to determine the gene expression profile of proliferating adult cardiomyocytes in the mammalian heart after myocardial ischaemia, to identify factors to can promote cardiac regeneration.

METHODS AND RESULTS

Here, we demonstrate increased 5-ethynyl-2'deoxyuridine incorporation in cardiomyocytes 3 days post-myocardial infarction in mice. By applying multi-colour lineage tracing, we show that this is paralleled by clonal expansion of cardiomyocytes in the borderzone of the infarcted tissue. Bioinformatic analysis of single-cell RNA sequencing data from cardiomyocytes at 3 days post ischaemic injury revealed a distinct transcriptional profile in cardiomyocytes expressing cell cycle markers. Combinatorial overexpression of the enriched genes within this population in neonatal rat cardiomyocytes and mice at postnatal day 12 (P12) unveiled key genes that promoted increased cardiomyocyte proliferation. Therapeutic delivery of these gene cocktails into the myocardial wall after ischaemic injury demonstrated that a combination of thymosin beta 4 (TMSB4) and prothymosin alpha (PTMA) provide a permissive environment for cardiomyocyte proliferation and thereby attenuated cardiac dysfunction.

CONCLUSION

This study reveals the transcriptional profile of proliferating cardiomyocytes in the ischaemic heart and shows that overexpression of the two identified factors, TMSB4 and PTMA, can promote cardiac regeneration. This work indicates that in addition to activating cardiomyocyte proliferation, a supportive environment is a key for regeneration to occur.

Provocative non-canonical roles of p53 and AKT signaling: A role for Thymosin β4 in medulloblastoma

The PI3K/AKT and p53 pathways are key regulators of cancer cell survival and death, respectively. Contrary to their generally accepted roles, several lines of evidence, including ours in medulloblastoma, the most common childhood brain cancer, highlight non-canonical functions for both proteins and show a complex context-dependent dynamic behavior in determining cell fate. Interestingly, p53-mediated cell survival and AKT-mediated cell death can dominate in certain conditions, and these interchangeable physiological functions may potentially be manipulated for better clinical outcomes. This review article presents studies in which p53 and AKT behave contrary to their well-established functions. We discuss the factors and circumstances that may be involved in mediating these changes and the implications of these unique roles of p53 and AKT in devising therapeutic strategies. Lastly, based on our recent finding of Thymosin beta 4-mediated chemosensitivity via an AKT-p53 interaction in medulloblastoma cells, we also discuss the possible implications of Thymosin beta-4 in enhancing drug sensitivity in this deadly childhood disease.

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.

Prothymosin Alpha: A Novel Contributor to Estradiol Receptor Alpha-Mediated CD8+ T-Cell Pathogenic Responses and Recognition of Type 1 Collagen in Rheumatic Heart Valve Disease

BACKGROUND

Rheumatic heart valve disease (RHVD) is a leading cause of cardiovascular death in low- and middle-income countries and affects predominantly women. The underlying mechanisms of chronic valvular damage remain unexplored and regulators of sex predisposition are unknown.

METHODS

Proteomics analysis of human heart valves (nondiseased aortic valves, nondiseased mitral valves [NDMVs], valves from patients with rheumatic aortic valve disease, and valves from patients with rheumatic mitral valve disease; n=30) followed by system biology analysis identified ProTα (prothymosin alpha) as a protein associated with RHVD. Histology, multiparameter flow cytometry, and enzyme-linked immunosorbent assay confirmed the expression of ProTα. In vitro experiments using peripheral mononuclear cells and valvular interstitial cells were performed using multiparameter flow cytometry and quantitative polymerase chain reaction. In silico analysis of the RHVD and Streptococcuspyogenes proteomes were used to identify mimic epitopes.

RESULTS

A comparison of NDMV and nondiseased aortic valve proteomes established the baseline differences between nondiseased aortic and mitral valves. Thirteen unique proteins were enriched in NDMVs. Comparison of NDMVs versus valves from patients with rheumatic mitral valve disease and nondiseased aortic valves versus valves from patients with rheumatic aortic valve disease identified 213 proteins enriched in rheumatic valves. The expression of the 13 NDMV-enriched proteins was evaluated across the 213 proteins enriched in diseased valves, resulting in the discovery of ProTα common to valves from patients with rheumatic mitral valve disease and valves from patients with rheumatic aortic valve disease. ProTα plasma levels were significantly higher in patients with RHVD than in healthy individuals. Immunoreactive ProTα colocalized with CD8⁺ T cells in RHVD. Expression of ProTα and estrogen receptor alpha correlated strongly in circulating CD8⁺ T cells from patients with RHVD. Recombinant ProTα induced expression of the lytic proteins perforin and granzyme B by CD8⁺ T cells as well as higher estrogen receptor alpha expression. In addition, recombinant ProTα increased human leukocyte antigen class I levels in valvular interstitial cells. Treatment of CD8⁺ T cells with specific estrogen receptor alpha antagonist reduced the cytotoxic potential promoted by ProTα. In silico analysis of RHVD and Spyogenes proteomes revealed molecular mimicry between human type 1 collagen epitope and bacterial collagen-like protein, which induced CD8⁺ T-cell activation in vitro.

CONCLUSIONS

ProTα-dependent CD8⁺ T-cell cytotoxicity was associated with estrogen receptor alpha activity, implicating ProTα as a potential regulator of sex predisposition in RHVD. ProTα facilitated recognition of type 1 collagen mimic epitopes by CD8⁺ T cells, suggesting mechanisms provoking autoimmunity.

Thymosin β4 Is an Endogenous Iron Chelator and Molecular Switcher of Ferroptosis

Thymosin β4 (Tβ4) 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. Tβ4 has also been implicated in tumor metastasis and neurodegeneration. However, the precise roles and mechanism(s) of action of Tβ4 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 Tβ4 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 Tβ4 in cell growing medium inhibits erastin and glutamate-induced ferroptosis in the macrophage cell line. Moreover, Tβ4 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 Tβ4 is an endogenous iron chelator and take part in iron homeostasis in the ferroptosis process. We discuss the literature data of parallel involvement of Tβ4 and ferroptosis in different human pathologies, mainly cancer and neurodegeneration. Our findings confronted with literature data show that controlled Tβ4 release could command on/off switching of ferroptosis and may provide novel therapeutic opportunities in cancer and tissue degeneration pathologies.

Thymosin β4 protects against aortic aneurysm via endocytic regulation of growth factor signaling

Vascular stability and tone are maintained by contractile smooth muscle cells (VSMCs). However, injury-induced growth factors stimulate a contractile-synthetic phenotypic modulation which increases susceptibility to abdominal aortic aneurysm (AAA). As a regulator of embryonic VSMC differentiation, we hypothesized that Thymosin β4 (Tβ4) may function to maintain healthy vasculature throughout postnatal life. This was supported by the identification of an interaction with low density lipoprotein receptor related protein 1 (LRP1), an endocytic regulator of platelet-derived growth factor BB (PDGF-BB) signaling and VSMC proliferation. LRP1 variants have been implicated by genome-wide association studies with risk of AAA and other arterial diseases. Tβ4-null mice displayed aortic VSMC and elastin defects that phenocopy those of LRP1 mutants, and their compromised vascular integrity predisposed them to Angiotensin II-induced aneurysm formation. Aneurysmal vessels were characterized by enhanced VSMC phenotypic modulation and augmented PDGFR-β signaling. In vitro, enhanced sensitivity to PDGF-BB upon loss of Tβ4 was associated with dysregulated endocytosis, with increased recycling and reduced lysosomal targeting of LRP1-PDGFR-β. Accordingly, the exacerbated aneurysmal phenotype in Tβ4-null mice was rescued upon treatment with the PDGFR-β antagonist Imatinib. Our study identifies Tβ4 as a key regulator of LRP1 for maintaining vascular health, and provides insights into the mechanisms of growth factor-controlled VSMC phenotypic modulation underlying aortic disease progression.

Multiple potential roles of thymosin β4 in the growth and development of hair follicles

The hair follicle (HF) is an important mini-organ of the skin, composed of many types of cells. Dermal papilla cells are important signalling components that guide the proliferation, upward migration and differentiation of HF stem cell progenitor cells to form other types of HF cells. Thymosin β4 (Tβ4), a major actin-sequestering protein, is involved in various cellular responses and has recently been shown to play key roles in HF growth and development. Endogenous Tβ4 can activate the mouse HF cycle transition and affect HF growth and development by promoting the migration and differentiation of HF stem cells and their progeny. In addition, exogenous Tβ4 increases the rate of hair growth in mice and promotes cashmere production by increasing the number of secondary HFs (hair follicles) in cashmere goats. However, the molecular mechanisms through which Tβ4 promotes HF growth and development have rarely been reported. Herein, we review the functions and mechanisms of Tβ4 in HF growth and development and describe the endogenous and exogenous actions of Tβ4 in HFs to provide insights into the roles of Tβ4 in HF growth and development.

Cardiomyocytes stimulate angiogenesis after ischemic injury in a ZEB2-dependent manner

The disruption in blood supply due to myocardial infarction is a critical determinant for infarct size and subsequent deterioration in function. The identification of factors that enhance cardiac repair by the restoration of the vascular network is, therefore, of great significance. Here, we show that the transcription factor Zinc finger E-box-binding homeobox 2 (ZEB2) is increased in stressed cardiomyocytes and induces a cardioprotective cross-talk between cardiomyocytes and endothelial cells to enhance angiogenesis after ischemia. Single-cell sequencing indicates ZEB2 to be enriched in injured cardiomyocytes. Cardiomyocyte-specific deletion of ZEB2 results in impaired cardiac contractility and infarct healing post-myocardial infarction (post-MI), while cardiomyocyte-specific ZEB2 overexpression improves cardiomyocyte survival and cardiac function. We identified Thymosin β4 (TMSB4) and Prothymosin α (PTMA) as main paracrine factors released from cardiomyocytes to stimulate angiogenesis by enhancing endothelial cell migration, and whose regulation is validated in our in vivo models. Therapeutic delivery of ZEB2 to cardiomyocytes in the infarcted heart induces the expression of TMSB4 and PTMA, which enhances angiogenesis and prevents cardiac dysfunction. These findings reveal ZEB2 as a beneficial factor during ischemic injury, which may hold promise for the identification of new therapies.

The LINC00961 transcript and its encoded micropeptide, small regulatory polypeptide of amino acid response, regulate endothelial cell function

AIMS

Long non-coding RNAs (lncRNAs) play functional roles in physiology and disease, yet understanding of their contribution to endothelial cell (EC) function is incomplete. We identified lncRNAs regulated during EC differentiation and investigated the role of LINC00961 and its encoded micropeptide, small regulatory polypeptide of amino acid response (SPAAR), in EC function.

METHODS AND RESULTS

Deep sequencing of human embryonic stem cell differentiation to ECs was combined with Encyclopedia of DNA Elements (ENCODE) RNA-seq data from vascular cells, identifying 278 endothelial enriched genes, including 6 lncRNAs. Expression of LINC00961, first annotated as an lncRNA but reassigned as a protein-coding gene for the SPAAR micropeptide, was increased during the differentiation and was EC enriched. LINC00961 transcript depletion significantly reduced EC adhesion, tube formation, migration, proliferation, and barrier integrity in primary ECs. Overexpression of the SPAAR open reading frame increased tubule formation; however, overexpression of the full-length transcript did not, despite production of SPAAR. Furthermore, overexpression of an ATG mutant of the full-length transcript reduced network formation, suggesting a bona fide non-coding RNA function of the transcript with opposing effects to SPAAR. As the LINC00961 locus is conserved in mouse, we generated an LINC00961 locus knockout (KO) mouse that underwent hind limb ischaemia (HLI) to investigate the angiogenic role of this locus in vivo. In agreement with in vitro data, KO animals had a reduced capillary density in the ischaemic adductor muscle after 7 days. Finally, to characterize LINC00961 and SPAAR independent functions in ECs, we performed pull-downs of both molecules and identified protein-binding partners. LINC00961 RNA binds the G-actin sequestering protein thymosin beta-4x (Tβ4) and Tβ4 depletion phenocopied the overexpression of the ATG mutant. SPAAR binding partners included the actin-binding protein, SYNE1.

CONCLUSION

The LINC00961 locus regulates EC function in vitro and in vivo. The gene produces two molecules with opposing effects on angiogenesis: SPAAR and LINC00961.

Thymosin beta 4 attenuates PrP(106-126)-induced human brain endothelial cells dysfunction

The blood-brain barrier (BBB) is a highly selective permeability barrier that separates the circulating blood from the brain and extracellular fluid in the central nervous system (CNS). The BBB is formed by cerebral endothelial cells connected by tight junctions. Prion diseases are neurodegenerative pathologies characterized by the accumulation of altered forms of the prion protein (PrP), named PrP^Sc. Thymosin beta 4 (Tβ₄) is an actin-sequestering peptide known to bind monomeric actin and inhibit its polymerization, and it is known to have a neuroprotective effect. However, the effect of Tβ₄ on prion disease has not yet been investigated. Therefore, in this study, we investigated the effect of Tβ₄ on prion-induced BBB dysfunction in hCMEC/D3 human cerebral endothelial cells. We found that Tβ₄ increased the expression of tight junction protein, but reduced the ratio of F-actin to G-actin. Moreover, we showed that Tβ₄ significantly improved PrP (106-126)-induced vascular permeability dysfunction in hCMEC/D3 cells. Through human BBB in vitro model, we found that PrP (106-126) could disrupt tight junctions and cytoskeleton arrangement. These results suggest that Tβ₄ may play a critical role in barrier stabilization. Furthermore, Tβ₄ may prevent neurodegenerative diseases caused by prion-induced BBB dysfunction.

Stress and immune response to bacterial LPS in the sea urchin Paracentrotus lividus (Lamarck, 1816)

The immune system of the sea urchin species Paracentrotus lividus is highly complex and, as yet, poorly understood. P. lividus coelomocytes mediate immune response through phagocytosis and encapsulation of non-self particles, in addition to the production of antimicrobial molecules. Despite this understanding, details of exactly how these processes occur and the mechanisms which drive them are still in need of clarification. In this study, we show how the bacterial lipopolysaccharides (LPS) is able to induce a stress response which increases the levels of the heat shock proteins HSP70 and HSP90 only a few hours after treatment. This study also shows that LPS treatment increases the expression of the β-thymosin-derivated protein paracentrin, the precursor of antimicrobial peptides.

Comparative study of β-thymosin in two scallop species Argopecten irradians and Chlamys farreri

The β-thymosin (Tβ) proteins participate in numerous biological processes, such as cell proliferation and differentiation, anti-inflammatory and antimicrobial mechanism. To date, Tβ proteins have been well studied in vertebrates, especially mammals. While limited Tβ or Tβ-like proteins have been reported in invertebrates. Moreover, rare information of Tβ or Tβ-like proteins is available in scallop species yet. In the present study, two Tβ homologues, AiTβ and CfTβ, were identified and characterized from two scallop species bay scallop Argopecten irradians and Zhikong scallop Chlamys farreri. They were both 41 amino acid peptide and contained one THY domain, a highly conserved actin-binding motif and two conserved helix forming regions. Tissue distribution and expression profiles of their mRNA transcripts were roughly similar yet different in detail, while their recombinant proteins exhibited different immunomodulation activity on the downstream immune parameters. These results collectively indicated that the function of Tβ family in scallop were functionally differentiated.

Molecular cloning, expression analysis, and the immune-related role of a thymosin β in the goldfish, Carassius auratus

β-Thymosins play critical roles in the regulation of many important physiological processes, but their function in teleost fishes remains poorly understood. In this study, the full-length cDNA coding for a thymosin β (Tβ) was cloned and identified in goldfish, Carassius auratus (gfTβ). The gfTβ cDNA consisted of 653 bp with an open reading frame of 135 bp that encodes a 44 amino acid polypeptide. Sequence analysis revealed one thymosin domain and a highly conserved actin-binding motif (¹⁸LKKTET²³). Expression of gfTβ transcript was detected ubiquitously in all tissues examined, with relatively higher levels in the brain, intestine, spleen, gill, skin, kidney, and testis. Cadmium and H₂O₂ exposure induced increases in gfTβ transcript levels in the liver and spleen. Moreover, gfTβ transcription was upregulated in response to LPS challenge in the spleen while Poly I:C treatment did not affect gfTβ expression. In vivo injection of recombinant gfTβ generated from an Escherichia coli system induced expression of T lymphocyte-related genes (RAG1 and CD8α). These results suggest that gfTβ may be involved in the immune response of teleost fishes via modulation of T lymphocyte development.

Thymosins participate in antibacterial immunity of kuruma shrimp, Marsupenaeus japonicus

Thymosins β are actin-binding proteins that play a variety of different functions in inflammatory responses, wound healing, cell migration, angiogenesis, and stem cell recruitment and differentiation. In crayfish, thymosins participate in antiviral immunology. However, the roles of thymosin during bacterial infection in shrimp remain unclear. In the present study, four thymosins were identified from kuruma shrimp, Marsupenaeus japonicus, and named as Mjthymosin2, Mjthymosin3, Mjthymosin4, and Mjthymosin5 according the number of their thymosin beta actin-binding motifs. Mjthymosin3 was selected for further study because its expression level was the highest in hemocytes. Expression analysis showed that Mjthymosin3 was upregulated in hemocytes after challenged by Vibrio anguillarum or Staphylococcus aureus. The recombinant Mjthymosin3 protein could inhibit the growth of certain bacteria in an in vitro antibacterial test. Mjthymosins could facilitate external bacterial clearance in shrimp, and were beneficial to shrimp survival post V. anguillarum or S. aureus infection. The results suggested that Mjthymosins played important roles in the antibacterial immune response of kuruma shrimp.

Expression and localisation of thymosin beta-4 in the developing human early fetal heart

BACKGROUND

The objective of this study was to investigate the expression and localisation of thymosin β4 (Tβ4) in the developing human heart. Tβ4 is a cardioprotective protein which may have therapeutic potential. While Tβ4 is an endogenously produced protein with known importance during development, its role within the developing human heart is not fully understood. Elucidating the localisation of Tβ4 within the developing heart will help in understanding its role during cardiac development and is crucial for understanding its potential for cardioprotection and repair in the adult heart.

METHODS

Expression of Tβ4 mRNA in the early fetal human heart was assessed by PCR using both ventricular and atrial tissue. Fluorescence immunohistochemistry was used to assess the localisation of Tβ4 in sections of early fetal human heart. Co-staining with CD31, an endothelial cell marker, and with myosin heavy chain, a cardiomyocyte marker, was used to determine whether Tβ4 is localised to these cell types within the early fetal human heart.

RESULTS

Tβ4 mRNA was found to be expressed in both the atria and the ventricles of the early fetal human heart. Tβ4 protein was found to be primarily localised to CD31-expressing endothelial cells and the endocardium as well as being present in the epicardium. Tβ4-associated fluorescence was greater in the compact layer of the myocardial wall and the interventricular septum than in the trabecular layer of the myocardium.

CONCLUSIONS

The data presented illustrates expression of Tβ4 in the developing human heart and demonstrates for the first time that Tβ4 in the human heart is primarily localised to endothelial cells of the cardiac microvasculature and coronary vessels as-well as to the endothelial-like cells of the endocardium and to the epicardium.

A thymosin repeated protein1 reduces white spot syndrome virus replication in red claw crayfish Cherax quadricarinatus

The β-thymosins are a group of structurally related, highly conserved intracellular small peptides in vertebrates with various biological functions, including cytoskeletal remodeling, neuronal development, cell migration, cell survival, tissue repair and inhibition of inflammation. In contrast to vertebrates, the function of β-thymosin is not fully understood in crustaceans. Previously, we found that a thymosin-repeated protein1 (CqTRP1) gene was up-regulated after white spot syndrome virus (WSSV) challenge in hematopoietic tissue (Hpt) cells from the red claw crayfish Cherax quadricarinatus. To further identify the effect of CqTRP1 on WSSV infection, a full length cDNA sequence of β-thymosin homologue was cloned and analyzed from red claw crayfish followed by functional study. The CqTRP1 cDNA contains an open reading frame of 387 nucleotides encoding a protein of 129 amino acids with a putative molecular mass of 14.3 kDa. The amino acid sequence showed high identity with other β-thymosins and contained three characteristic thymosin β actin-binding motifs, suggesting that CqTRP1 was a member of the β-thymosin family. Tissue distribution analysis revealed a ubiquitous presence of CqTRP1 in all the examined tissues with the highest expression in hemocytes, Hpt and gonad at the transcriptional level. Interestingly, the gene silencing of endogenous CqTRP1 by RNAi enhanced the WSSV replication in Hpt cells. Meanwhile, the WSSV replication was significantly reduced in the Hpt cell cultures if overloaded with a recombinant CqTRP1. Taken together, these data clearly indicated that CqTRP1 was likely to be associated with the anti-WSSV response in a crustacean C. quadricarinatus, which provides new strategy against white spot disease in crustacean aquaculture.

Effects of overexpression and inhibited expression of thymosin, an actin-interacting protein from Bombyx mori, on BmNPV proliferation and replication

Previous study showed that exogenously applied recombinant thymosin from Bombyx mori (BmTHY) reduces B. mori nucleopolyhedrovirus (BmNPV) proliferation in silkworm. Which stands to reason that BmTHY in B. mori is crucial for the defense against BmNPV. However, little is known about the effect of endogenously overexpressed or repressed BmTHY on B. mori resistance to virus infection. To study this issue, we constructed an overexpression and inhibited expression systems of BmTHY in BmN cells. The viral titer and the analysis from the quantitative real-time polymerase chain reaction (PCR) revealed that overexpression of BmTHY decreased the copies of BmNPV gene gp41, which goes over to inhibit the proliferation of BmNPV in BmN cells, while the inhibited expression of BmTHY significantly enhanced viral proliferation in infected BmN cells. These results indicated that endogenous BmTHY can inhibit BmNPV proliferation and replication in infected BmN cells. Furthermore, Co-IP showed that BmTHY could bind to actin in BmN cells. Also, the overexpression or inhibited expression of BmTHY shifted the ratio of F/G-actin in infected BmN cells. Lastly, the BmTHY, an actin-interacting protein, might be one of the key host factors against BmNPV, which inhibits viral proliferation and replication in BmN cells.

Thymosin β4 is involved in the antimicrobial immune response of Golden pompano, Trachinotus ovatus

Thymosin beta belongs to the thymosin family, which consists of a series of highly conserved peptides involved in various biological processes. In teleosts, understanding of the immunological functions of thymosin beta is limited, particularly in vivo, which is essentially unknown. In the current study, we cloned and identified thymosin beta 4 from the teleost fish Golden pompano (Trachinotus ovatus), which we have named TroTβ4. We investigated the expression patterns and functions of TroTβ4 in both in vivo and in vitro assays. TroTβ4 is composed of 44 amino acids and shares high sequence identities with known thymosin β4 species in other teleosts, which contains a highly conserved actin-binding motif (LKKTET). The expression of TroTβ4 was most abundant in immune organs, and was significantly up-regulated in response to infection bacterial with one of a number of bacteria (including Edwardsiella tarda, Vibrio harveyi, and Streptococcus agalactiae). Purified recombinant TroTβ4 (rTroTβ4) inhibited the growth of bacteria, as measured using an automatic growth curve analyzer, indicating that TroTβ4 has antimicrobial functions. When administered in vivo, overexpression of TroTβ4 in T. ovatus, bacterial colonization of tissues was significantly reduced. In contrast, when a DNA vector-based siRNA technology was used to knock down TroTβ4 expression, bacterial dissemination and colonization of tissues increased significantly. Taken together, these results provide the first in vivo evidence to indicate that teleost thymosin beta 4 plays a significant role in innate antibacterial immune responses in addition to in vitro bacteriostatic activity. This provides valuable information regarding the biological functions of teleost thymosin beta.

Thymosin beta 4 silencing suppresses proliferation and invasion of non-small cell lung cancer cells by repressing Notch1 activation

Thymosin beta 4 (Tβ4), a pleiotropic actin-sequestering polypeptide that is involved in wound healing and developmental processes, has been reported to be strongly associated with tumorigenesis. A recent tissue microarray analysis showed that Tβ4 was highly expressed in certain tumor cells, including lung cancer. However, the exact expression pattern and the role of Tβ4 in non-small cell lung cancer (NSCLC) have not to our knowledge been investigated. In the present study, we confirmed that Tβ4 expression was increased in NSCLC tissues and cell lines. Tβ4 gene silencing in A549 and H1299 cells inhibited cell proliferation, migration, and invasion in vitro and decreased tumor growth in vivo Mechanistic investigations revealed a significant decrease in Notch1 activation in Tβ4 gene-silenced cells. Moreover, restoring the Notch1 expression attenuated the function of Tβ4 silencing in NSCLC cells. Taken together, these findings suggest that Tβ4 may play an oncogenic role in NSCLC progression and may be a novel molecular target for anti-NSCLC therapy.

Thymosin From Bombyx mori Is Down-Regulated in Expression by BmNPV Exhibiting Antiviral Activity

Thymosins have been highly conserved during evolution. These hormones exist in many animal species and play an essential role in many biological events. However, little is known regarding the physiological function of silkworm Bombyx mori thymosin (BmTHY). In this study, we investigated the expression pattern of BmTHY in a Bombyx mori larval ovarian cell line (BmN) challenged with Bombyx mori nuclear polyhydrosis virus (BmNPV) and the antiviral effect of recombinant BmTHY (rBmTHY) for Bombyx mori against BmNPV. Western-blot assay and qRT-PCR analysis revealed that the level of BmTHY protein expression and transcription decreased over time when BmN cells were infected by BmNPV. Treatment with endotoxin-free rBmTHY led to a significant reduction in viral titer in the supernatant of BmN cells challenged with BmNPV. The results from antiviral tests performed in vitro and in vivo showed that endotoxin-free rBmTHY improved the survival rate of Bombyx mori infected with BmNPV. These findings suggest that BmTHY exerts immunomodulatory effects on Bombyx mori, rendering them resistant to viral infection.

A Tobacco-Derived Thymosin β4 Concatemer Promotes Cell Proliferation and Wound Healing in Mice

Thymosin β4 (Tβ4) is a peptide that is known to play important roles in protection, regeneration, and remodeling of injured tissues in humans, and that shows great promise in a range of clinical applications. However, current strategies to Tβ4 are insufficient to meet growing demand and have a number of limitations. In this current study we investigated whether expression of recombinant Tβ4 in plants, specifically in tobacco (Nicotiana tabacum) leaves, represents an effective approach. To address this question, a 168 bp Tβ4 gene optimized for tobacco codon usage bias was constitutively expressed in tobacco as a 4-unit repeat concatemer, fused to a polyhistidine tag. Quantitative polymerase chain reaction and Western blot analyses were used to verify 4×Tβ4 expression in 14 transgenic tobacco lines and enzyme-linked immunosorbent assay analysis indicated 4×Tβ4 protein concentrations as high as 3 μg/g of fresh weight in the leaves. We observed that direct administration of tobacco-derived Tβ4 was more effective than Tβ4 either obtained commercially or derived from expression in Escherichia coli at promoting splenocyte proliferation in vitro and wound healing in mice through an endothelial migration assay. This study provides new insights into the development of plant-derived therapeutic proteins and their application by direct administration.

Prothymosin-α Variants Elicit Anti-HIV-1 Response via TLR4 Dependent and Independent Pathways

BACKGROUND

Prothymosin α (ProTα) (isoform 2: iso2) is a widely distributed, small acidic protein with intracellular and extracellular-associated functions. Recently, we identified two new ProTα variants with potent anti-HIV activity from CD8+ T cells and cervicovaginal lavage. The first is a splice variant of the ProTα gene known as isoB and the second is the product of ProTα pseudogene 7 (p7). Similarly to iso2, the anti-HIV activity of both variants is mediated by type I IFN. Here we tested whether the immunomodulatory activity of isoB and p7 are also TLR4 dependent and determined their kinetic of release in response to HIV-1 infection.

METHODS

Type I, type III, TNF-α and IL-6 mRNA inducing activity was determined in macrophages from wild type and TLR4 knockout mice treated with recombinant ProTα variants. Supernatants from mock and HIV infected cells were analyzed by mass spectrometry in positive and negative modes for the presence of ProTα variants. In silico structural and functional analysis of ProTα variants were performed.

RESULTS

We show that both isoB and p7 upregulate IFN-β, IFN-λ1, IL-6, TNF-α and RANTES mRNAs in primary human macrophages. The potent stimulation of IFN-β by the recombinant ProTα variants in human macrophages is dependent on the TLR4 pathway, whereas the induction of TNF-α and IL-6 may also occur independently of TLR4, suggesting the interaction of ProTα variants with other signaling molecules/receptors. In silico analyses confirmed that the novel isoB and p7 variants are intrinsically disordered proteins, which lack the NLS and mass spectrometry showed release of ProTα variants within minutes post HIV-1 infection. These features are consistent with the function of ProTα variants as damage associate molecular patterns (DAMPs).

CONCLUSIONS

Our findings indicate that ProTα variants strongly inhibit viral replication mainly, but not exclusively, through TLR4 signaling and that they are released within minutes of viral infection suggesting that they may function as DAMPs.

Function of Thymosin Beta-4 in Ethanol-Induced Microglial Activation

BACKGROUND/AIMS

Neuroinflammation mediated by activated microglia may play a pivotal role in a variety of central nervous system (CNS) pathologic conditions, including ethanol-induced neurotoxicity. The purpose of this study was to investigate the function of Tβ4 in ethanol-induced microglia activation.

METHODS

Quantitative real-time PCR was conducted to assess the expression of Tβ4 and miR-339-5p. Western blot analysis was used to measure the expression of Tβ4, phosphorylated p38, ERK, JNK, Akt, and NF-x03BA;B p65. The concentration of TNF-α and IL-1β was determined using ELISA. NO concentration was measured using a nitric oxide colorimetric BioAssay Kit. Double immunofluorescence was performed to determine Tβ4 expression, in order to assess microglial activation in neonatal mouse FASD model.

RESULTS

Increased Tβ4 expression was observed in ethanol treated microglia. Knockdown of Tβ4 enhanced ethanol-induced inflammatory mediators tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) and nitric oxide (NO) in BV-2 cells was performed. Exogenous Tβ4 treatment significantly inhibited expression and secretion of these inflammatory mediators. Tβ4 treatment attenuated p38, ERK MAPKs, and nuclear factor-kappa B (NF-x03BA;B) pathway activation, and enhanced miR-339-5p expression induced by ethanol exposure in microglia. A neonatal mouse fetal alcohol spectrum disorders (FASD) model showed that Tβ4 expression in the microglia of the hippocampus was markedly enhanced, while Tβ4 treatment effectively blocked the ethanol-induced increase in inflammatory mediators, to the level expressed in vehicle-treated control animals.

CONCLUSION

This study is the first to demonstrate the function of Tβ4 in ethanol-induced microglia activation, thus contributing to a more robust understanding of the role of Tβ4 treatment in CNS disease.

A thymosin beta-4 is involved in production of hemocytes and immune defense of Hong Kong oyster, Crassostrea hongkongensis

Thymosin beta-4 (Tβ4) is a ubiquitous protein with multiple and diverse intracellular and extracellular functions in vertebrates. In this study, the full-length cDNA of Tβ4 was cloned and identified in Crassostrea hongkongensis, designated as ChTβ4. The full-length cDNA of ChTβ4 consists of 530 bp with an open reading frame of 126 bp encoding a 41 amino acid polypeptide. SMART analysis indicated that there is one thymosin domain and a highly conserved actin-binding motif (18LKKTET23) in ChTβ4. In vivo injection of recombinant ChTβ4 protein could significantly increase total hemocytes count in oysters, and knockdown of the expression of ChTβ4 resulted in a significant decrease in the circulating hemocytes. Tissue distribution analysis revealed a ubiquitous presence of ChTβ4, with the highest expression in hemocytes. The upregulated transcripts of ChTβ4 in response to bacterial challenge and tissue injury suggest that ChTβ4 is involved in both innate immunity against pathogen infection and wound healing. Moreover, bacteria-clearance experiment showed ChTβ4 could facilitate the clearance of injected bacteria in oysters. In vivo injection with ChTβ4 resulted in reduction of the intracellular ROS in hemocytes, which was associated with increased expression of antioxidant enzymes Cu/Zn superoxide dismutase (SOD), Catalase, and Glutathione Peroxidase (GPX) by pre-treatment with ChTβ4. These results suggest that ChTβ4 is a thymosin beta-4 homolog and plays a vital role in the immune defense of C. hongkongensis.

Tongue sole (Cynoglossus semilaevis) prothymosin alpha: Cytokine-like activities associated with the intact protein and the C-terminal region that lead to antiviral immunity via Myd88-dependent and -independent pathways respectively

Prothymosin alpha (ProTα) is a small protein that in mammals is known to participate in diverse biological processes including immunomodulation. In teleost, the immunological function of ProTα is unknown. In the current study, we investigated the expression and function of the ProTα (named CsProTα) from the teleost fish tongue sole (Cynoglossus semilaevis). We found that CsProTα expression was abundant in immune relevant tissues and upregulated by megalocytivirus infection. Immunoblot detected secretion of CsProTα by peripheral blood leukocytes. Recombinant CsProTα (rCsProTα) as well as the C-terminal 11-residue (Ct11) were able to bind head kidney monocytes (HKM) and induce immune gene expression; however, the induction patterns caused by rCsProTα and Ct11 differed considerably. When introduced in vivo, rCsProTα and Ct11 significantly reduced megalocytivirus infection in fish tissues, whereas rCsProTα antibody significantly promoted viral replication. Blocking of Myd88 activity abolished the virus-inhibitory effect of rCsProTα but not Ct11. Taken together, these results demonstrate for the first time that both the intact protein and the C-terminal segment of a teleost ProTα can act like cytokines and induce antiviral immunity via, however, distinct signaling pathways that differ in the requirement of Myd88.

Molecular and Physiological Characterization of Two Novel Multirepeat β-Thymosins from Silkworm, Bombyx mori

β-thymosin plays important roles in the development of the lymphatic system and the central nervous system in vertebrates. However, its role and function in invertebrates remain much less explored. Here, we firstly isolated a gene encoding β-thymosin in silkworm (Bombyx mori L.). Interestingly, this gene encodes two polypeptides, named as BmTHY1 and BmTHY2, via two different modes of RNA splicing. The recombinant proteins fused with an N-term GST tag were over-expressed in Escherichia coli (E. coli) and further purified to near homogenity to prepare mouse antibodies. The Western blot analysis showed that these proteins were expressed in various tissues and organs, as well as in different developmental stages. Amazingly, the expression of BmTHY2 was hugely increased during the pupae stage, indicating a specialized role in this period. The expression of these proteins was gradually decreased in BmN cells infected by BmNPV, suggesting they may play different roles in the virus infection. In addition, both BmTHY1 and BmTHY2 can interact with 14-3-3 of silkworm and Ubiquitin of BmNPV as shown by GST pull down and Co-IP assays, consistent with their roles in the regulation of the development of nervous system.

Thymosin-β4 is a determinant of drug sensitivity for Fenretinide and Vorinostat combination therapy in neuroblastoma

Retinoids are an important component of neuroblastoma therapy at the stage of minimal residual disease, yet 40-50% of patients treated with 13-cis-retinoic acid (13-cis-RA) still relapse, indicating the need for more effective retinoid therapy. Vorinostat, or Suberoylanilide hydroxamic acid (SAHA), is a potent inhibitor of histone deacetylase (HDAC) classes I & II and has antitumor activity in vitro and in vivo. Fenretinide (4-HPR) is a synthetic retinoid which acts on cancer cells through both nuclear retinoid receptor and non-receptor mechanisms. In this study, we found that the combination of 4-HPR + SAHA exhibited potent cytotoxic effects on neuroblastoma cells, much more effective than 13-cis-RA + SAHA. The 4-HPR + SAHA combination induced caspase-dependent apoptosis through activation of caspase 3, reduced colony formation and cell migration in vitro, and tumorigenicity in vivo. The 4-HPR and SAHA combination significantly increased mRNA expression of thymosin-beta-4 (Tβ4) and decreased mRNA expression of retinoic acid receptor α (RARα). Importantly, the up-regulation of Tβ4 and down-regulation of RARα were both necessary for the 4-HPR + SAHA cytotoxic effect on neuroblastoma cells. Moreover, Tβ4 knockdown in neuroblastoma cells increased cell migration and blocked the effect of 4-HPR + SAHA on cell migration and focal adhesion formation. In primary human neuroblastoma tumor tissues, low expression of Tβ4 was associated with metastatic disease and predicted poor patient prognosis. Our findings demonstrate that Tβ4 is a novel therapeutic target in neuroblastoma, and that 4-HPR + SAHA is a potential therapy for the disease.

β-Thymosins participate in antiviral immunity of red swamp crayfish (Procambarus clarkii)

β-Thymosins participate in numerous biological activities, including cell proliferation and differentiation, wound healing, and anti-inflammatory and antimicrobial activities. Many studies have investigated vertebrate β-thymosins, whereas few reports have focused on invertebrate β-thymosins. In this study, nine isoforms of β-thymosins (PcThy-1 to PcThy-8) were identified from the red swamp crayfish Procambarus clarkii. The isoforms contained different numbers of the thymosin β actin-binding motif. PcThy-1 contained one thymosin β actin-binding motif, whereas PcThy-8 contained eight motifs. Western blot analysis with anti-PcThy-4 antibody showed that three to six isoforms were present in one tissue, and PcThy-4, PcThy-5, PcThy-6, and PcThy-7 were the main isoforms in several tissues. Time course expression analysis of PcThys at the protein level showed that PcThy-4 was upregulated in hemocytes and gills after white spot syndrome virus (WSSV) challenge. PcThy-4, which contained four thymosin β actin-binding motifs, was selected for further research. Tissue distribution analysis by quantitative real-time PCR showed that PcThy-4 was present in tissues of the hemocytes, heart, hepatopancreas, gills, stomach, and intestine at the transcriptional level. Transcriptional expression profiles showed that PcThy-4 was upregulated after WSSV challenge. In vivo RNAi and protein injection assay results showed that PcThy-4 inhibited the replication of WSSV in crayfish and enhanced the survival rate after WSSV infection. Furthermore, PcThy-4 promoted hemocyte phagocytosis of WSSV. Overall, results suggested that PcThys protected crayfish from WSSV infection and played an important role in antiviral immune response.

Functional analysis of Pacific oyster (Crassostrea gigas) β-thymosin: Focus on antimicrobial activity

An antimicrobial peptide, ∼5 kDa in size, was isolated and purified in its active form from the mantle of the Pacific oyster Crassostrea gigas by C18 reversed-phase high-performance liquid chromatography. Matrix-assisted laser desorption ionisation time-of-flight analysis revealed 4656.4 Da of the purified and unreduced peptide. A comparison of the N-terminal amino acid sequence of oyster antimicrobial peptide with deduced amino acid sequences in our local expressed sequence tag (EST) database of C. gigas (unpublished data) revealed that the oyster antimicrobial peptide sequence entirely matched the deduced amino acid sequence of an EST clone (HM-8_A04), which was highly homologous with the β-thymosin of other species. The cDNA possessed a 126-bp open reading frame that encoded a protein of 41 amino acids. To confirm the antimicrobial activity of C. gigas β-thymosin, we overexpressed a recombinant β-thymosin (rcgTβ) using a pET22 expression plasmid in an Escherichia coli system. The antimicrobial activity of rcgTβ was evaluated and demonstrated using a bacterial growth inhibition test in both liquid and solid cultures.

Thymosin Beta-4 Induces Mouse Hair Growth

Thymosin beta-4 (Tβ4) is known to induce hair growth and hair follicle (HF) development; however, its mechanism of action is unknown. We generated mice that overexpressed Tβ4 in the epidermis, as well as Tβ4 global knockout mice, to study the role of Tβ4 in HF development and explore the mechanism of Tβ4 on hair growth. To study Tβ4 function, we depilated control and experimental mice and made tissue sections stained with hematoxylin and eosin (H&E). To explore the effect of Tβ4 on hair growth and HF development, the mRNA and protein levels of Tβ4 and VEGF were detected by real-time PCR and western blotting in control and experimental mice. Protein expression levels and the phosphorylation of P38, ERK and AKT were also examined by western blotting. The results of depilation indicated that hair re-growth was faster in Tβ4-overexpressing mice, but slower in knockout mice. Histological examination revealed that Tβ4-overexpressing mice had a higher number of hair shafts and HFs clustered together to form groups, while the HFs of control mice and knockout mice were separate. Hair shafts in knockout mice were significantly reduced in number compared with control mice. Increased Tβ4 expression at the mRNA and protein levels was confirmed in Tβ4-overexpressing mice, which also had increased VEGF expression. On the other hand, knockout mice had reduced levels of VEGF expression. Mechanistically, Tβ4-overexpressing mice showed increased protein expression levels and phosphorylation of P38, ERK and AKT, whereas knockout mice had decreased levels of both expression and phosphorylation of these proteins. Tβ4 appears to regulate P38/ERK/AKT signaling via its effect on VEGF expression, with a resultant effect on the speed of hair growth, the pattern of HFs and the number of hair shafts.

Characterization of two thymosins as immune-related genes in common carp (Cyprinus carpio L.)

Prothymosin alpha (ProTα) and thymosin beta (Tβ) belong to thymosin family, which consists of a series of highly conserved peptides involved in stimulating immune responses. ProTα b and Tβ are still poorly studied in teleost. Here, the full-length cDNAs of ProTα b and Tβ-like (Tβ-l) were cloned and identified in common carp (Cyprinus carpio L.). The expressions of carp ProTα b and Tβ-l exhibited rise-fall pattern and then trended to be stable during early development. After spring viraemia of carp virus (SVCV) infection, the carp ProTα b and Tβ-l transcripts were significantly up-regulated in some immune-related organs. When transiently over-expressed carp ProTα b and Tβ-l in zebrafish, these two proteins up-regulated the expressions of T lymphocytes-related genes (Rag 1, TCR-γ, CD4 and CD8α). These results suggest that carp ProTα b and Tβ may ultimately enhance the immune response during viral infection and modulate the development of T lymphocytes in teleost.

Prothymosin α variants isolated from CD8+ T cells and cervicovaginal fluid suppress HIV-1 replication through type I interferon induction

Soluble factors from CD8(+) T cells and cervicovaginal mucosa of women are recognized as important in controlling human immunodeficiency virus type 1 (HIV-1) infection and transmission. Previously, we have shown the strong anti-HIV-1 activity of prothymosin α (ProTα) derived from CD8(+) T cells. ProTα is a small acidic protein with wide cell distribution, to which several functions have been ascribed, depending on its intracellular or extracellular localization. To date, activities of ProTα have been attributed to a single protein known as isoform 2. Here we report the isolation and identification of 2 new ProTα variants from CD8(+) T cells and cervicovaginal lavage with potent anti-HIV-1 activity. The first is a splice variant of the ProTα gene, known as isoform CRA_b, and the second is the product of a ProTα gene, thus far classified as a pseudogene 7. Native or recombinant ProTα variants potently restrict HIV-1 replication in macrophages through the induction of type I interferon. The baseline expression of interferon-responsive genes in primary human cervical tissues positively correlate with high levels of intracellular ProTα, and the knockdown of ProTα variants by small interfering RNA leads to downregulation of interferon target genes. Overall, these findings suggest that ProTα variants are innate immune mediators involved in immune surveillance.

Thymosin beta 4 may translocate from the cytoplasm in to the nucleus in HepG2 cells following serum starvation. An ultrastructural study

Due to its actin-sequestering properties, thymosin beta-4 (Tβ4) is considered to play a significant role in the cellular metabolism. Several physiological properties of Tβ4 have been reported;, however, many questions concerning its cellular function remain to be ascertained. To better understand the role of this small peptide we have analyzed by means of transmission immunoelectron microscopy techniques the ultrastructural localization of Tβ4 in HepG2 cells. Samples of HepG2 cells were fixed in a mixture of 3% formaldehyde and 0.1% glutaraldehyde in 0.1 M cacodylate buffer and processed for standard electron microscopic techniques. The samples were dehydrated in a cold graded methanol series and embedded in LR gold resin. Ultrathin sections were labeled with rabbit antibodies to Tβ4, followed by gold-labeled goat anti-rabbit, stained with uranyl acetate and bismuth subnitrate, observed and photographed in a JEOL 100S transmission electron microscope. High-resolution electron microscopy showed that Tβ4 was mainly restricted to the cytoplasm of HepG2 growing in complete medium. A strong Tβ4 reactivity was detected in the perinuclear region of the cytoplasmic compartment where gold particles appeared strictly associated to the nuclear membrane. In the nucleus specific Tβ4 labeling was observed in the nucleolus. The above electron microscopic results confirm and extend previous observations at light microscopic level, highlighting the subcellular distribution of Tβ4 in both cytoplasmic and nuclear compartments of HepG2 cells. The meaning of Tβ4 presence in the nucleolus is not on the best of our knowledge clarified yet. It could account for the interaction of Tβ4 with nucleolar actin and according with this hypothesis, Tβ4 could contribute together with the other nucleolar acting binding proteins to modulate the transcription activity of the RNA polymerases.

Thymosin beta4 regulates cardiac valve formation via endothelial-mesenchymal transformation in zebrafish embryos

Thymosin beta4 (TB4) has multiple functions in cellular response in processes as diverse as embryonic organ development and the pathogeneses of disease, especially those associated with cardiac coronary vessels. However, the specific roles played by TB4 during heart valve development in vertebrates are largely unknown. Here, we identified a novel function of TB4 in endothelialmesenchymal transformation (EMT) in cardiac valve endocardial cushions in zebrafish. The expressions of thymosin family members in developing zebrafish embryos were determined by whole mount in situ hybridization. Of the thymosin family members only zTB4 was expressed in the developing heart region. Cardiac valve development at 48 h post fertilization was defected in zebrafish TB4 (zTB4) morpholino-injected embryos (morphants). In zTB4 morphants, abnormal linear heart tube development was observed. The expressions of bone morphogenetic protein (BMP) 4, notch1b, and hyaluronic acid synthase (HAS) 2 genes were also markedly reduced in atrio-ventricular canal (AVC). Endocardial cells in the AVC region were stained with anti-Zn5 antibody reactive against Dm-grasp (an EMT marker) to observe EMT in developing cardiac valves in zTB4 morphants. EMT marker expression in valve endothelial cells was confirmed after transfection with TB4 siRNA in the presence of transforming growth factor β (TGFβ) by RT-PCR and immunofluorescent assay. Zn5-positive endocardial AVC cells were not observed in zTB4 morphants, and knockdown of TB4 suppressed TGF-β-induced EMT in ovine valve endothelial cells. Taken together, our results demonstrate that TB4 plays a pivotal role in cardiac valve formation by increasing EMT.1.

Generation of mature Nα-terminal acetylated thymosin α 1 by cleavage of recombinant prothymosin α

N(α)-terminal acetylation of peptides plays an important biological role but is rarely observed in prokaryotes. N(α)-terminal acetylated thymosin α1 (Tα1), a 28-amino-acid peptide, is an immune modifier that has been used in the clinic to treat hepatitis B and C virus (HBV/HCV) infections. We previously documented N(α)-terminal acetylation of recombinant prothymosin α (ProTα) in E. coli. Here we present a method for production of N(α)-acetylated Tα1 from recombinant ProTα. The recombinant ProTα was cleaved by human legumain expressed in Pichia pastoris to release Tα1 in vitro. The N(α)-acetylated Tα1 peptide was subsequently purified by reverse phase and cation exchange chromatography. Mass spectrometry indicated that the molecular mass of recombinant N(α)-acetylated Tα1 was 3108.79 in, which is identical to the mass of N(α)-acetylated Tα1 produced by total chemical synthesis. This mass corresponded to the nonacetylated Tα1 mass with a 42 Da increment. The retention time of recombinant N(α)-acetylated Tα1 and chemosynthetic N(α)-acetylated Tα1 were both 15.4 min in RP-high performance liquid chromatography (HPLC). These data support the use of an E. coli expression system for the production of recombinant human N(α)-acetylated Tα1 and also will provide the basis for the preparation of recombinant acetylated peptides in E. coli.

Gene expression of tissue-specific molecules in ex vivo Dermacentor variabilis (Acari: Ixodidae) during rickettsial exposure

Ticks serve as both vectors and the reservoir hosts capable of transmitting spotted fever group Rickettsia by horizontal and vertical transmission. Persistent maintenance of Rickettsia species in tick populations is dependent on the specificity of the tick and Rickettsia relationship that limits vertical transmission of particular Rickettsia species, suggesting host-derived mechanisms of control. Tick-derived molecules are differentially expressed in a tissue-specific manner in response to rickettsial infection; however, little is known about tick response to specific rickettsial species. To test the hypothesis that tissue-specific tick-derived molecules are uniquely responsive to rickettsial infection, a bioassay to characterize the tick tissue-specific response to different rickettsial species was used. Whole organs of Dermacentor variabilis (Say) were exposed to either Rickettsia montanensis or Rickettsia amblyommii, two Rickettsia species common, or absent, in field-collected D. variabilis, respectively, for 1 and 12 h and harvested for quantitative real time-polymerase chain reaction assays of putative immune-like tick-derived factors. The results indicated that tick genes are differently expressed in a temporal and tissue-specific manner. Genes encoding glutathione S-transferase 1 (dvgst1) and Kunitz protease inhibitor (dvkpi) were highly expressed in midgut, and rickettsial exposure downregulated the expression of both genes. Two other genes encoding glutathione S-transferase 2 (dvgst2) and beta-thymosin (dvpbeta-thy) were highly expressed in ovary, with dvbeta-thy expression significantly downregulated in ovaries exposed to R. montanensis, but not R. amblyommii, at 12-h postexposure, suggesting a selective response. Deciphering the tissue-specific molecular interactions between tick and Rickettsia will enhance our understanding of the key mechanisms that mediate rickettsial infection in ticks.

A tumor-penetrating peptide modification enhances the antitumor activity of thymosin alpha 1

A serious limitation of numerous antitumor drugs is the incapacity to penetrate solid tumors. However, addition of an RGD fragment to peptide drugs might solve this problem. In this study, we explored whether the introduction of a permeability-enhancing sequence, such as iRGD (CRGDK/RGPD/EC) fragments, would enhance the activity of thymosin alpha 1 (Tα1). The modified Tα1 (Tα1-iRGD) was successfully expressed and purified, and the in vitro assay showed that Tα1-iRGD presented a similar activity as Tα1 in promoting proliferation of mouse splenocytes. Meanwhile, cell adhesion analysis revealed that Tα1-iRGD exhibited more specific and greater binding with tumor cells compared with Tα1. Furthermore, the iRGD fragment evidently enhanced the basal ability of Tα1 to inhibit proliferation of cancer cells in vitro, particularly of mouse melanoma cell line B16F10 and human lung cancer cell line H460. Our findings indicated that the addition of an iRGD fragment increased the anti-proliferative activity of Tα1 against cancer cells by improving the ability of Tα1 to penetrate the tumor cells. This study highlighted the important roles of an iRGD sequence in the therapeutic strategy of Tα1-iRGD. Thus, Tα1-iRGD could be a novel drug candidate for cancer treatment.

Differential gene expression in the brain of the African lungfish, Protopterus annectens, after six days or six months of aestivation in air

The African lungfish, Protopterus annectens, can undergo aestivation during drought. Aestivation has three phases: induction, maintenance and arousal. The objective of this study was to examine the differential gene expression in the brain of P. annectens during the induction (6 days) and maintenance (6 months) phases of aestivation as compared with the freshwater control using suppression subtractive hybridization. During the induction phase of aestivation, the mRNA expression of prolactin (prl) and growth hormone were up-regulated in the brain of P. annectens, which indicate for the first time the possible induction role of these two hormones in aestivation. Also, the up-regulation of mRNA expression of tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein γ polypeptide and the down-regulation of phosphatidylethanolamine binding protein, suggest that there could be a reduction in biological and neuronal activities in the brain. The mRNA expression of cold inducible RNA-binding protein and glucose regulated protein 58 were also up-regulated in the brain, probably to enhance their cytoprotective effects. Furthermore, the down-regulation of prothymosin α expression suggests that there could be a suppression of transcription and cell proliferation in preparation for the maintenance phase. In general, the induction phase appeared to be characterized by reduction in glycolytic capacity and metabolic activity, suppression of protein synthesis and degradation, and an increase in defense against ammonia toxicity. In contrast, there was a down-regulation in the mRNA expression of prl in the brain of P. annectens during the maintenance phase of aestivation. In addition, there could be an increase in oxidative defense capacity, and up-regulation of transcription, translation, and glycolytic capacities in preparation for arousal. Overall, our results signify the importance of reconstruction of protein structures and regulation of energy expenditure during the induction phase, and the needs to suppress protein degradation and conserve metabolic fuel stores during the maintenance phase of aestivation.

Characterization of thymosin β4 in mammals' saliva

Thymosin β4 (Tβ4) is a low molecular weight peptide found in several mammalian tissues and is known mainly by its ability to bind cytoskeletal actin, influencing cell migration and differentiation, and promoting tissue repair. Considering the functional role of this peptide, the main goal of this work was to characterize Tβ4 in mammals' saliva by using evolutionary and proteomic tools. For this, mammalian Tβ4 sequences were retrieved from NCBI, SwissProt and Ensembl databases. The alignment of Tβ4 amino acid sequences showed a high degree of conservation between species. The gene seems to be evolving under negative selection as indicated by a dN/dS ratio of 0.05. Whole saliva was collected from dog, human, rabbit, cow, horse and sheep and the salivary peptides were isolated through filtration and analyzed by LC-MS/MS. Spectra was processed against the database constructed with the retrieved Tβ4 sequences. For the first time, the identification of this peptide was achieved in rat, dog, horse and bovine saliva. Detection in these mammal species and its amino acid conservation suggest an important role of Tβ4 in the homeostasis of the mammalian oral cavity.

Nanog suppresses cell migration by downregulating thymosin β4 and Rnd3

Nanog, Sox2, and Oct4 are key transcription factors critical for the pluripotency and self-renewal of embryonic stem (ES) cells. Their downregulations lead to differentiation, accompanied with changes in cell motility. Whether these factors impact cell motility directly, however, is not clear. Here we addressed this question by initially assessing their effect in non-stem cells. We found that the ectopic expression of Nanog, Sox2, or Oct4 markedly inhibited ECV304 cell migration. Detailed examinations revealed that Nanog induced disorganizations of the actin cytoskeleton and peripheral localizations of focal adhesions. These effects required its DNA-binding domain and are thus transcription dependent. Furthermore, thymosin β4 and Rnd3 were identified as its downstream targets. Their depletions in ECV304 cells by RNAi phenocopied the ectopic expression of Nanog in both cell motility and actin organization, whereas their ectopic expressions rescued the migration defect of Nanog overexpression. Both proteins were upregulated during mouse ES cell differentiation. Their levels in the pluripotent mouse P19 cells also increased upon Nanog ablation, coincident with an increase in cell motility. Moreover, persistent expression of Nanog in zebrafish embryos suppressed gastrulation and cell migration. These results indeed suggest a dual role of certain transcription factors in the orchestration of differentiation and motility.

Intraocular expression of thymosin β4 in proliferative diabetic retinopathy

PURPOSE

To examine an association between thymosin β4 as potentially angioproliferative factor and proliferative diabetic retinopathy.

METHODS

The clinical study part included 62 patients with proliferative diabetic retinopathy (PDR) (study group) and 24 patients with non-diabetic pre-retinal membranes (control group). All patients underwent pars plana vitrectomy. We examined the thymosin β4 concentration in vitreous and plasma; and the expression of thymosin β4, glial fibrillary acidic protein (GFAP) and CD31 (PECAM-1 or Platelet Endothelial Cell Adhesion Molecule) and the levels of thymosin β4 mRNA and vascular endothelial growth factor (VEGF) mRNA in the excised membranes. The experimental study part consisted of 24 Sprague--Dawley rats with streptozotocin-induced diabetes mellitus and 24 age-matched control animals without diabetes. We determined the mRNA concentrations of thymosin β4, VEGF and GFAP in the rat retinas.

RESULTS

In the clinical study part, the vitreal and plasma thymosin β4 concentrations were significantly higher in the study group than control group (p =0.04 and p=0.01, respectively), and were significantly (p=0.028) correlated with each other. Co-expression of thymosin β4 and CD31 was observed in the diabetic fibrovascular membranes. Thymosin β4 mRNA and VEGF mRNA levels were significantly (p<0.01) higher in diabetic membranes than in non-diabetic membranes. In the experimental study part, the diabetic retinas showed co-localization of thymosin β4 and GFAP. The mRNA levels of thymosin β4, VEGF and GFAP were significantly (p<0.01) higher in diabetic rats than in control animals.

CONCLUSIONS

Thymosin β4 was produced in intraocular fibrovascular membranes of patients with PDR and in rats with experimental diabetes mellitus. Thymosin β4 may play a role in diabetic retinal neovascularization.

[Biotechnological production of acetylated thymosin beta4]

Thymosin beta4 (43 aa) is a highly conserved acidic peptide which regulates actin polymerization in mammalian cells by sequestering globular actin. Thymosin beta4 is undergoing clinical trials as a drug for the treatment of venous stasis ulcers, corneal wounds and injuries, as well as acute myocardial infarction. Currently, thymosin beta4 is produced with solid-phase chemical synthesis. Biotechnological synthesis of this peptide presents difficulties because N-terminal amino acid residue of thymosin beta4 is acetylated. In this study we propose a method for producing the recombinant precursor of thymosin beta4 and its subsequent targeted chemical acetylation. Desacetylthymosin beta4 was synthesized as a part of a hybrid protein with thioredoxin and a specific TEV (tobacco etch virus) protease cleavage site. The following scheme was developed for the purification of desacetylthymosin beta4: (i) the biosynthesis of a soluble hybrid protein (HP) in Escherichia coli; (ii) isolation of the HP by ion exchange chromatography; (iii) cleavage of the HP with TEVprotease; (iv) purification of desacetylthymosin beta4 by ultra-filtration. N-terminal acetylation of desacetylthymosin beta4 was performed with acetic anhydride under acidic conditions (pH 3). The reaction yield was 55%. Thymosin beta4 was then purified by reverse-phase high performance liquid chromatography. The proposed synthetic approach to recombinant thymosin beta4 is suitable for scale-up and can provide for the medical use of highly purified preparation with a yield of 20 mg from 1 L of culture.

[Prothymosin alpha interacts with C-terminal domain of histone H1 and dissociates p53-histone H1 complex]

A novel mode of the tumor suppressor protein p53 regulation, mediated by recruitment of the linker histone H1 to the promoters of p53 target genes leading to specific repression of p53-dependent transcription, has recently been uncovered. Yet, how this repression could be relieved is not clear. Previously, a histone-binding nuclear protein prothymosin alpha (ProTa) was shown to trigger a p53 response. The histone-binding region of ProTa was found to be essential for this effect, raising a possibility that ProTa stimulates p53-dependent transcription by dissociating the p53-histone H1 repressive complex. Here, we have shown that ProTa interacts with the same C-terminal domain of histone H1 as p53 does and, therefore, ProTa and p53 could compete for binding to histone H1. Furthermore, ProTa, when competent for histone H1 binding, is able to liberate p53 from the histone H1-p53 complex in vitro. In vivo, stimulation of p53-dependent transcription by ProTa correlates with ability of ProTa to interact with histone H1. Ectopic expression of histone H1 or its C-terminal ProTa-binding domain specifically suppresses the stimulating effect of ProTa on transcription of the p53-responsive reporter gene in cultured cells. These results are consistent with the model that ProTa may enhance p53 transcription activity by displacement of histone H1 from p53-H1 repressive complex.

Molecular cross-talk between the NRF2/KEAP1 signaling pathway, autophagy, and apoptosis

Oxidative stress, perturbations in the cellular thiol level and redox balance, affects many cellular functions, including signaling pathways. This, in turn, may cause the induction of autophagy or apoptosis. The NRF2/KEAP1 signaling pathway is the main pathway responsible for cell defense against oxidative stress and maintaining the cellular redox balance at physiological levels. The relation between NRF2/KEAP1 signaling and regulation of apoptosis and autophagy is not well understood. In this hypothesis article we discuss how KEAP1 protein and its direct interactants (such as PGAM5, prothymosin α, FAC1 (BPTF), and p62) provide a molecular foundation for a possible cross-talk between NRF2/KEAP1, apoptosis, and autophagy pathways. We present a hypothesis for how NRF2/KEAP1 may interfere with the cellular apoptosis-regulatory machinery through activation of the ASK1 kinase by a KEAP1 binding partner-PGAM5. Based on very recent experimental evidence, new hypotheses for a cross-talk between NF-κB and the NRF2/KEAP1 pathway in the context of autophagy-related "molecular hub" protein p62 are also presented. The roles of KEAP1 molecular binding partners in apoptosis regulation during carcinogenesis and in neurodegenerative diseases are also discussed.

Production of Nα-acetylated thymosin α1 in Escherichia coli

BACKGROUND

Thymosin α1 (Tα1), a 28-amino acid Nα-acetylated peptide, has a powerful general immunostimulating activity. Although biosynthesis is an attractive means of large-scale manufacture, to date, Tα1 can only be chemosynthesized because of two obstacles to its biosynthesis: the difficulties in expressing small peptides and obtaining Nα-acetylation. In this study, we describe a novel production process for Nα-acetylated Tα1 in Escherichia coli.

RESULTS

To obtain recombinant Nα-acetylated Tα1 efficiently, a fusion protein, Tα1-Intein, was constructed, in which Tα1 was fused to the N-terminus of the smallest mini-intein, Spl DnaX (136 amino acids long, from Spirulina platensis), and a His tag was added at the C-terminus. Because Tα1 was placed at the N-terminus of the Tα1-Intein fusion protein, Tα1 could be fully acetylated when the Tα1-Intein fusion protein was co-expressed with RimJ (a known prokaryotic Nα-acetyltransferase) in Escherichia coli. After purification by Ni-Sepharose affinity chromatography, the Tα1-Intein fusion protein was induced by the thiols β-mercaptoethanol or d,l-dithiothreitol, or by increasing the temperature, to release Tα1 through intein-mediated N-terminal cleavage. Under the optimal conditions, more than 90% of the Tα1-Intein fusion protein was thiolyzed, and 24.5 mg Tα1 was obtained from 1 L of culture media. The purity was 98% after a series of chromatographic purification steps. The molecular weight of recombinant Tα1 was determined to be 3107.44 Da by mass spectrometry, which was nearly identical to that of the synthetic version (3107.42 Da). The whole sequence of recombinant Tα1 was identified by tandem mass spectrometry and its N-terminal serine residue was shown to be acetylated.

CONCLUSIONS

The present data demonstrate that Nα-acetylated Tα1 can be efficiently produced in recombinant E. coli. This bioprocess could be used as an alternative to chemosynthesis for the production of Tα1. The described methodologies may also be helpful for the biosynthesis of similar peptides.