No effect of thymosin beta-4 on the expression of the transcription factor Islet-1 in the adult murine heart

The transcription factor Islet-1 marks a progenitor cell population of the second heart field during cardiogenesis. In the adult heart Islet-1 expression is limited to the sinoatrial node, the ventricular outflow tract, and parasympathetic ganglia. The regenerative effect in the injured mouse ventricle of thymosin beta-4 (TB4), a 43-aminoacid peptide, was associated with increased Islet-1 immunostaining, suggesting the induction of an Islet-1-positive progenitor state by TB4. Here we aimed to reassess this effect in a genetic model. Mice from the reporter mouse line Isl1-nLacZ were primed with TB4 and subsequently underwent myocardial infarction. Islet-1 expression was assessed 2, 7, and 14 days after infarction. We detected only a single Islet-1+ cell in 8 TB4 treated and infarcted hearts which located outside of the sinoatrial node, the outflow tract or cardiac ganglia (in ~2500 sections). Two cells were identified in 5 control infarcted hearts. TB4 did not induce LacZ positivity in ventricular explants cultures of Isl1-nLacZ mice nor did it affect the density of LacZ+ cells in explant cultures of nLacZ+ regions of the heart. In summary, we found no evidence that TB4 reactivates Islet-1 expression in adult mouse ventricle.

Thymosin β4 Reduces H₂O₂ Induced Oxidative Stress in MC3T3-E1 Cells on Titanium Surface

Thymosin β4 (Tβ4) is known to inhibit an inflammatory response and to increase the survival of osteoblasts on titanium (Ti) surfaces. Ti is the most widely used graft material in dentistry; however, an inflammatory response induced following implant placement results in the generation of reactive oxygen species (ROS). The oxidative stress from the production of ROS such as nitric oxide (NO) and hydrogen peroxide (H2O2) can damage surrounding cells, resulting in implant failure by decreasing cell viability. Thus, the aim of this study was to determine the biological effects of Tβ4 on the oxidative stress induced to MC3T3-E1 preosteoblasts on the Ti surface. Based on an MTT assay and bromodeoxyuridine immunofluorescence staining, Tβ4 was found to increase the proliferation of the H2O2-exposed MC3T3-E1 cells on Ti discs. Reverse transcription-polymerase chain reaction and western blot analyses showed that Tβ4 decreased the mRNA and protein expression levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in H2O2-exposed MC3T3-E1 cells on the Ti discs. Tβ4 inhibited the synthesis of intracellular ROS and the secretion of NO and prostaglandin E2 (PGE2) from H2O2-exposed MC3T3-E1 cells on the Ti discs. In conclusion, Tβ4 inhibits H2O2-induced iNOS and COX-2 expression with a decrease in ROS, NO, and PGE2 synthesis, which leads to improved cell survival with low cytotoxicity under an oxidative stress condition in MC3T3-E1 cells on the Ti surface. This suggests that Tβ4 may be a crucial molecule to reduce oxidative stress-induced cell damage or hypoxia, leading to promoted osseointegration on the Ti surface during implant placement.

Thymosin β4 alleviates renal fibrosis and tubular cell apoptosis through TGF-β pathway inhibition in UUO rat models

BACKGROUND

Thymosin β4 (Tβ4) is closely associated with the cytoskeleton, inflammation, wound healing, angiogenesis, apoptosis, and myocardial regeneration, but the effects of Tβ4 treatment on chronic renal tubular interstitial fibrosis (CRTIF) are poorly known. This study aimed to examine the effects of Tβ4 on the renal apoptosis and the expression of transforming growth factor (TGF-β), E-cadherin, and α-smooth muscle actin (α-SMA) in CRTIF rat models.

METHODS

Male SD rats were randomized into four groups (sham group, unilateral ureteral obstruction (UUO) group, UUO + low-dose Tβ4 group, and UUO + high-dose Tβ4 group). The pathological changes of kidney tissue and its function were assessed two weeks after UUO. In renal interstitial tissue,TGF-β, E-cadherin and α-SMA expression was detected by western blot. In tubular epithelial cells, E-cadherin and α-SMA expression was detected using Real-time qPCR and western blot. Cell apoptosis of rat renal interstitial tissue and tubular epithelial cells was evaluated by immunofluorescence and western blot.

RESULTS

Two weeks after UUO, no differences in blood urea nitrogen and creatinine were observed between the four groups (P > 0.05). Compared to the UUO group, Tβ4 treatment decreased the 24-h proteinuria (P < 0.001) and reduced the area of pathological change (P < 0.01); this effect was more apparent in the UUO + high-dose Tβ4 group. Compared to the UUO group, a significant decrease in TGF-β and α-SMA protein expression was observed in the high-dose Tβ4 group. The level of E-cadherin protein was lower in the UUO group than the Tβ4 groups, and high-dose Tβ4 treatment further increased E-cadherin expression and improved cell apoptosis in the renal interstitial tissue. Analysis of in vitro tubular epithelial cells showed that α-SMA mRNA and protein expression decreased, while E-cadherin mRNA and protein expression increased by Tβ4 treatment. Similarly, these changes were more significant in the UUO + high-dose Tβ4 group. Tβ4 treatment improved the apoptosis of In vitro tubular epithelial cells compared with pure TGF-β stimulation, and equally, the decrease of apoptosis was more apparent in the TGF-β + high-dose Tβ4 group.

CONCLUSIONS

Tβ4 treatment might alleviate the renal fibrosis and apoptosis of tubular epithelial cells through TGF-β pathway inhibition in UUO rats with CRTIF.

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.

Safety and efficacy of autologous thymosin β4 pre-treated endothelial progenitor cell transplantation in patients with acute ST segment elevation myocardial infarction: A pilot study

BACKGROUND

Experimental studies and clinical trials suggest that endothelial progenitor cell (EPC) transplantation can repair "broken" heart. However, transplantation of autologous EPCs has numerous limitations, including the limited supply of expanded EPCs, the impaired function and activity of the transplanted cells and so on. Therefore, we investigated the feasibility, safety and initial clinical outcome of autologous thymosin β4 (Tβ4) pre-treated EPC transplantation in patients with acute ST segment elevation myocardial infarction (STEMI).

METHODS

Ten patients with STEMI were included; they were randomized to 2 groups: EPC transplantation group (control group; n = 5) and Tβ4-pre-treated EPC transplantation group (experimental group; n = 5). EPCs were pre-treated with Tβ4 24 hours before transplantation in experimental group. Cardiac function was evaluated using echocardiography and emission computed tomography, as well as the 6-min walking test before and 6 months after the intervention.

RESULTS

After 6 months of follow-up, the average 6-min walking distance was increased by 38.2 m (from 263 ± 42 m to 302 ± 34 m) in the control group and 75.7 m (from 264 ± 42 m to 340 ± 44 m) in the experimental group; the average difference of the 6-min walking distance was 37.5 m (95% confidence interval [CI], 28.7-56.3 m; P < 0.01). In addition, the cardiac function in the experimental group was more significantly improved than that of the control group. There were no severe complications related to the procedure in either group during the follow-up.

DISCUSSION

Our pilot study suggested that Tβ4-optimized EPC transplantation appeared to be feasible and safe, and might have beneficial effects on exercise capacity and left ventricular function in patients with STEMI.

Thymosin Beta-4 Suppresses Osteoclastic Differentiation and Inflammatory Responses in Human Periodontal Ligament Cells

Background

Recent reports suggest that thymosin beta-4 (Tβ4) is a key regulator for wound healing and anti-inflammation. However, the role of Tβ4 in osteoclast differentiation remains unclear.

Purpose

The purpose of this study was to evaluate Tβ4 expression in H₂O₂-stimulated human periodontal ligament cells (PDLCs), the effects of Tβ4 activation on inflammatory response in PDLCs and osteoclastic differentiation in mouse bone marrow-derived macrophages (BMMs), and identify the underlying mechanism.

Methods

Reverse transcription-polymerase chain reactions and Western blot analyses were used to measure mRNA and protein levels, respectively. Osteoclastic differentiation was assessed in mouse bone marrow-derived macrophages (BMMs) using conditioned medium (CM) from H₂O₂-treated PDLCs.

Results

Tβ4 was down-regulated in H₂O₂-exposed PDLCs in dose- and time-dependent manners. Tβ4 activation with a Tβ4 peptide attenuated the H₂O₂-induced production of NO and PGE₂ and up-regulated iNOS, COX-2, and osteoclastogenic cytokines (TNF-α, IL-1β, IL-6, IL-8, and IL-17) as well as reversed the effect on RANKL and OPG in PDLCs. Tβ4 peptide inhibited the effects of H₂O₂ on the activation of ERK and JNK MAPK, and NF-κB in PDLCs. Furthermore, Tβ4 peptide inhibited osteoclast differentiation, osteoclast-specific gene expression, and p38, ERK, and JNK phosphorylation and NF-κB activation in RANKL-stimulated BMMs. In addition, H₂O₂ up-regulated Wnt5a and its cell surface receptors, Frizzled and Ror2 in PDLCs. Wnt5a inhibition by Wnt5a siRNA enhanced the effects of Tβ4 on H₂O₂-mediated induction of pro-inflammatory cytokines and osteoclastogenic cytokines as well as helping osteoclastic differentiation whereas Wnt5a activation by Wnt5a peptide reversed it.

Conclusion

In conclusion, this study demonstrated, for the first time, that Tβ4 was down-regulated in ROS-stimulated PDLCs as well as Tβ4 activation exhibited anti-inflammatory effects and anti-osteoclastogenesis in vitro. Thus, Tβ4 activation might be a therapeutic target for inflammatory osteolytic disease, such as periodontitis.

Neuroprotective impact of prothymosin alpha-derived hexapeptide against retinal ischemia-reperfusion

Prothymosin alpha (ProTα) has robustness roles against brain and retinal ischemia or serum-starvation stress. In the ProTα sequence, the active core 30-amino acid peptide/P30 (a.a.49-78) is necessary for the original neuroprotective actions against ischemia. Moreover, the 9-amino acid peptide sequence/P9 (a.a.52-60) in P30 still shows neuroprotective activity against brain and retinal ischemia, though P9 is less potent than P30. As the previous structure-activity relationship study for ProTα may not be enough, the possibility still exists that any sequence smaller than P9 retains potent neuroprotective activity. When different P9- and P30-related peptides were intravitreally injected 24h after retinal ischemia in mice, the 6-amino acid peptide/P6 (NEVDEE, a.a.51-56) showed potent protective effects against ischemia-induced retinal functional deficits, which are equipotent to the level of P30 peptide in electroretinography (ERG) and histological damage in Hematoxylin and Eosin (HE) staining. Further studies using ERG and HE staining suggested that intravitreal or intravenous (i.v.) injection with modified P6 peptide/P6Q (NEVDQE) potently inhibited retinal ischemia-induced functional and histological damage. In an immunohistochemical analysis, the ischemia-induced loss of retinal ganglion, bipolar, amacrine and photoreceptor cells were inhibited by a systemic administration with P6Q peptide 24h after the ischemic stress. In addition, systemic post-treatment with P6Q peptide significantly inhibited retinal ischemia-induced microglia and astrocyte activation in terms of increased ionized calcium-binding adaptor molecule 1 (Iba-1) and glial fibrillary acidic protein (GFAP) intensity, respectively, as well as their morphological changes, increased number and migration. Thus, this study demonstrates the therapeutic significance of modified P6 peptide P6Q (NEVDQE) derived from 6-amino acid peptide (P6) in ProTα against ischemic damage.

[The Effects of Thymosin alpha1 on Immune Function of Mice after Skin Transplantation]

OBJECTIVE

By establishing C57-BABL/c mice allogeneic skin transplantation model, to analyze the immune system function with the administration of thymosin al (Tal) in mouse after skin transplantation; and to explore the mechanism of specific immune tolerance induced by Tal in vivo.

METHODS

80 C57 mice and 80 BABL/c mice were used as donor and acceptor respectively to establish C57-BABL/c mice allogeneic skin transplantation model and divided into four groups: Group A, control group (without any treatment, n=20); Group B, CsA treatment group (CsA 10 mg/kg, n=20); Group C, Tal treatment group (Tal 400 microg/kg, n=20) and Group D, combination therapy group (CsA 10 mg/kg & Talphal 400 microg/kg, n=20). In the three experimental group, the drug of each group were respectively administrated by intraperitoneal injection daily, for 21 d. The survival of skin graft were observed and recorded, the Luminexx MAP for cytokine detection were performed in 1, 7, 14, 21 d after treatment, skin grafts were taking for HE staining, and flow cytometry were performed for lymphocyte phenotype.

RESULTS

After transplantation, in 1, 7, 14, 21 d, the cytokine of Group B, C and ID compared to Group A, as well as Group D to B&C respectively, shows a decreaing of IL-1, IL-2, IL-6, IL-17 value and increasing of IL-10 significantly (P<0.05) at the same time point; While no statistical significance shows between Group B and C. Compared with other groups, Group D have a high ratio of CD4/CD8, and a high percentage of CD4+ CD25+ T cells (P<0.05).

CONCLUSION

Administrated Tal after transplantation, can decrease the graft damage from T cells, but could not prevent rejection.

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.

Effect of thymosin α₁ on the phenotypic and functional maturation of dendritic cells from children with acute lymphoblastic leukemia

To determine the effect of thymosin α1 (Tα1) on the phenotypic and functional maturation of HL‑60 cells, freeze‑thaw antigen‑loaded dendritic cells (DCs) were derived from peripheral blood mononuclear cells (PBMCs) of children with acute lymphoblastic leukemia (ALL). The DCs were generated from the PBMC samples that were collected from the PB of 10 consecutive ALL children. On day 3 of culturing, the cells in the antigen + no Tα1 (AN) and antigen + Tα1 (AT) groups were incubated with 100 µl lysates obtained from freeze‑thaw cycling. After 5 days of incubation, the AT group was administered with 100 ng/ml Tα1. On day 8, the DCs were stained with fluorescein isothiocyanate‑conjugated cluster of differentiation (CD)1a, CD83 and HLA‑DR antibodies and analyzed by flow cytometry. In addition, the killing activity of cytotoxic T lymphocytes (CTLs) from the different groups on wild‑type leukemia cells was measured. The DCs in the AT group exhibited more apparent, characteristic dendritic morphologies than the control and AN group DCs. Furthermore, the lowest expression level of CD1a, and the highest expression of CD83 and HLA‑DR were observed in the AT group when compared with the AN and control groups (P<0.05). The lactate dehydrogenase release assay demonstrated that the killing rate of CTL in the AT group was significantly higher than that in the control and AN groups (P<0.01). Thus, Tα1 may markedly promote the phenotypic and functional maturation of DCs, and may serve as a suitable immunomodulator of DC‑based immunotherapy for treatment of hematological malignancies.

The Effect of Thymosin β4 for Osteoblast Adhesion on Titanium Surface

Titanium (Ti) is the most widely used implant material in dentistry and orthopedics but the release of metal ions from Ti implants results in increased bone resorption by enhancing the production of inflammatory cytokines from the macrophages and facilitating osteoclast differentiation. Thymosin β4 (Tβ4) has several biological activities, such as promoting wound healing, angiogenesis, cell proliferation and migration in mammalian cells. This study examined the role of Tβ4 in osteoblasts via focal adhesions (FAs) and ERK1/2 signaling related to cell adhesion and proliferation for cell survival on the Ti surface. As a result, cell adhesion and proliferation increased in the Tβ4 treated cells (Tβ4/MC3T3-E1) but was significantly lower in the Tβ4 knock-down cells by Tβ4-siRNA (si-Tβ4/MC3T3-E1) than that of the untreated cells. The levels of FAK phosphorylation, paxillin expression, and paxillin localization were higher in the Tβ4/IMC3T3-E1 cells than that of the untreated cells but lower in the si-Tβ4/MC3T3-E1 cells. In addition, the levels of cell proliferation, Grb2 and Ras protein expression and phosphorylation of ERK1/2 were higher in the Tβ4/MC3T3-E1 cells than in the untreated cells but lower in the si-Tβ4/IMC3T3-E1 cells. These results suggest that Tβ4 might be a good nanomolecule that promotes osteoblast survival by facilitating adhesion and proliferation on the Ti surface.

[The influence of the thymus peptides on analgesia caused by acute and chronic immobilization]

OBJECTIVE

Our aim was to investigate the influence of thymic polypeptides on pain sensitivity and to analyze a possible role of the opioid system in the implementation of the analgesia caused by immobilization stress.

METHODS

The study was performed on male Wistar rats at the Moscow state University named after M. V. Lomonosov. We studied effects of thymus peptides: thymuline (0.15 mg/kg), fraction 5 thymosin (0.25 microgram/kg) and cattle thymus extracted product (CTEP) (0.5 mg/kg) on pain sensitivity in rats using test "tail flick" without stress, with acute (3 h) and sub acute (12 h) immobilization stress. The comparison groups were animals treated with saline and spleen polypeptides.

RESULTS

It is shown that preparations of thymus increase the threshold of pain sensitivity in the intact animals. Immobilization stress duration 3 and 12 h in thymus peptides treated rats caused a less pronounced increase in pain threshold than in the control groups (immobilization stress 3 h: CTEP--p = 0.025, thymuline--p = 0.022, fraction 5 thymosin--p = 0.033; immobilization stress 12 h: CTEP--p = 0.034, thymuline--p = 0.027, fraction 5 thymosin--p = 0.036). The opioid receptor blocker naloxone (1 mg/kg) did not completely block the stress-induced analgesia, indicating the presence of both opioid and non -opioid components in this state. In thymus peptides treated rats, opioid component was less pronounced than in the control groups (CTEP--p = 0.031, thymuline--p = 0.026, fraction 5 thymosin--p = 0.029).

CONCLUSION

Pre-activation of the opioid system by the thymus polypeptides leads to an increase in the share of non-opioid component of the stress-induced analgesia and prevents the depletion of the opioid system in immobilization stress.

[Triplet anti-tumor therapy based on thymosin α-1 attenuates incidence of hepatoma and serum alpha-fetoprotein level in rat hepatoma model]

OBJECTIVE

To explore the impact of triple anti-tumor therapy based on thymosin α1 (Tα1) combined with Huaier granule(HG) and sirolimus on the level of serum alpha-fetoprotein (AFP) in rat models of liver cancer.

METHODS

Ninety Sprague-Dawley rats were randomly divided into triple anti-tumor therapy group, Tα1 group, HG group, sirolimus group, positive control and blank control groups, with 15 rats in each group. Except the blank control group, the rats in the other groups were induced using diethylnitrosamine (DEN) to establish liver cancer models. After DEN treatment, the triple therapy group underwent 0.8 mg/kg Tα1 subcutaneous injection (from once a day for two weeks to twice a week since the third week), 0.35 g/kg HG gavage (three times a day) and 1 mg/kg sirolimus gavage (once a day). The dose of the rest single drug groups were the same with that of the triple therapy group. The positive control and blank control groups were not treated with the drugs. The treatment lasted 20 weeks. Then, the behavior of the rats were observed at the different time points, and the level of serum AFP in the rats were detected at 6, 16, 18, 20 weeks, respectively.

RESULTS

The typical symptoms of liver cancer were seen in the DEN-induced rats at 16 weeks. Since the tenth week, 6 rats died one after another. Pathological section of rat liver tissue suggested that the rat models were established successfully. According to the incidence rate of liver cancer and the survival rate at 20 weeks, the triple anti-tumor therapy was significantly superior to the single drug treatments. In addition, the triple anti-tumor therapy significantly reduced the level of serum AFP in the rats.

CONCLUSION

The triple anti-tumor therapy can significantly prolong the survival time of rats with liver cancer, decrease the cancer incidence rate and the level of serum AFP.

Human serum thymic factor in detecting acute T cell leukemia

In acute leukemia, the frequency of the E+ cells among the blood mononuclears before and after their incubation with human serum thymic factor was investigated by means of the E rosette assay. In 4 of 24 patients tested, the thymic factor incubation of their peripheral blood cells increased the number of the E+ cells among the mononuclears. Prospective importance of the test either in investigating whether a T0 leukemia might really exist, or in monitoring possible variations of the immature T cell counts in relationship to the patient's treatment and his disease course, are discussed.

Effect of thymosin beta 4 in the presence of up-regulation of the insulin-like growth factor-1 signaling pathway on high-glucose-exposed vascular endothelial cells

Thymosin beta 4 (Tβ4), which regulates vascular cell growth, can ameliorate some of the problems associated with diabetes. However, the precise signaling mechanisms by which Tβ4 protects against hyperglycemia-induced damage to endothelial cells have not been investigated in detail. Thus, the aim of this study was to elucidate the role of Tβ4 in diabetes and the possible involvement of insulin-like growth factor-1 (IGF-1), which affects cellular survival, metabolism, and glucose homeostasis in high-glucose (HG)-injured human umbilical vein endothelial cells (HUVECs). Immunoblotting assays revealed that under HG blockade conditions, Tβ4 did not alter the insulin-signaling pathway, but induced overexpression of IGF-1 protein, leading to activation of factors in alternative signaling pathway. Small interfering RNA of Tβ4 and IGF-1 were studied to clarify relationship between Tβ4 and IGF-1. These findings suggest that IGF-1 induction by Tβ4 ameliorates the damage in HG-injured HUVECs which manifest as diabetic vascular disorder.

Therapeutic Benefit of Extended Thymosin β4 Treatment Is Independent of Blood Glucose Level in Mice with Diabetic Peripheral Neuropathy

Peripheral neuropathy is a chronic complication of diabetes mellitus. To investigated the efficacy and safety of the extended treatment of diabetic peripheral neuropathy with thymosin β4 (Tβ4), male diabetic mice (db/db) at the age of 24 weeks were treated with Tβ4 or saline for 16 consecutive weeks. Treatment of diabetic mice with Tβ4 significantly improved motor (MCV) and sensory (SCV) conduction velocity in the sciatic nerve and the thermal and mechanical latency. However, Tβ4 treatment did not significantly alter blood glucose levels. Treatment with Tβ4 significantly increased intraepidermal nerve fiber density. Furthermore, Tβ4 counteracted the diabetes-induced axon diameter and myelin thickness reductions and the g-ratio increase in sciatic nerve. In vitro, compared with dorsal root ganglia (DRG) neurons derived from nondiabetic mice, DRG neurons derived from diabetic mice exhibited significantly decreased neurite outgrowth, whereas Tβ4 promoted neurite growth in these diabetic DRG neurons. Blockage of the Ang1/Tie2 signaling pathway with a neutralized antibody against Tie2 abolished Tβ4-increased neurite outgrowth. Our data demonstrate that extended Tβ4 treatment ameliorates diabetic-induced axonal degeneration and demyelination, which likely contribute to therapeutic effect of Tβ4 on diabetic neuropathy. The Ang1/Tie2 pathway may mediate Tβ4-induced axonal remodeling.

Thymosin Beta 4 protects mice from monocrotaline-induced pulmonary hypertension and right ventricular hypertrophy

Pulmonary hypertension (PH) is a progressive vascular disease of pulmonary arteries that impedes ejection of blood by the right ventricle. As a result there is an increase in pulmonary vascular resistance and pulmonary arterial pressure causing right ventricular hypertrophy (RVH) and RV failure. The pathology of PAH involves vascular cell remodeling including pulmonary arterial endothelial cell (PAEC) dysfunction and pulmonary arterial smooth muscle cell (PASMC) proliferation. Current therapies are limited to reverse the vascular remodeling. Investigating a key molecule is required for development of new therapeutic intervention. Thymosin beta-4 (Tβ4) is a ubiquitous G-actin sequestering protein with diverse biological function and promotes wound healing and modulates inflammatory responses. However, it remains unknown whether Tβ4 has any protective role in PH. The purpose of this study is to evaluate the whether Tβ4 can be used as a vascular-protective agent. In monocrotaline (MCT)-induced PH mouse model, we showed that mice treated with Tβ4 significantly attenuated the systolic pressure and RVH, compared to the MCT treated mice. Our data revealed for the first time that Tβ4 selectively targets Notch3-Col 3A-CTGF gene axis in preventing MCT-induced PH and RVH. Our study may provide pre-clinical evidence for Tβ4 and may consider as vasculo-protective agent for the treatment of PH induced RVH.

[Effects of thymosin alpha1 on immune effector molecules of mouse]

OBJECTIVE

To analysis the effects of Talpha1 on the immune effector molecules in mouse immune system.

METHODS

Sixty five BABL/c mice were divided into four groups: CsA group (n=20), Talpha1 group (n= 20), CsA+Talpha1 group (n=20) and control group (n=5). In the 3 experimental groups, 10 mg/kg CsA, 400 microg/ kg Talpha1, 10 mg/kg CsA+400 microg/kg Talpha1 were respectively administrated by intraperitoneal injection daily. Luminex was performed for cytokine detection at 1 d, 7 d, 14 d, 21 d day after the above treatments. Lymphocyte culture was prepared with the mouse spleen suspension, and then treated with 0. 25 mg/mL CsA, 10 microg/mL Talpha1 or 0.25 mg/mL CsA+10 microg/mL Talpha1 in vitro, respectively. Three days later, OD values of each treated lymphocyte culture and several cytokines in the culture were measured.

RESULTS

Compared with other groups, CsA+Talpha1 group had significant lower IL-1alpha, IL-2, IL-6, IL-17, and significant higher IL-10 at 1 d, 7 d, 14 d, 21 d after the treatments (P < 0.05). Three days after the culture, OD value in the control group was significantly higher than that in Talppha1 group, CsA group, and CsA+ Talpha1 group (P < 0.05). IL-1alpa and IL-6 in the control group were significantly higher than those in the experiment groups (P < 0.05), while IL-10 in the control group was significantly lower than that in the experiment groups (P < 0.05). IL-2 and IL-17 were similar.

CONCLUSION

Talpha1 show regulatory effect on the immune effector molecules which could promote Th1 cells transforming to Th2 cells.

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.

[Protective effect of thymosin β4 against oxidative damage in cultured rabbit corneal epithelial cells]

OBJECTIVE

The aim of this study was to investigate the effects of thymosin β4 (Tβ4) against oxidative damage in rabbit corneal epithelial cells in vitro.

METHODS

Experimental study. Primary cultures of rabbit corneal epithelial cells were isolated and cultured from cornea tissue explants. Cell morphology was observed by phase-contrast microscope. The expression of keratin 12 and connexin 43 in cultured cells were examined with RT-PCR. The cultures were divided into 4 groups: control group, Tβ4 group, hydrogen peroxide (H2O2) group, and H2O2+Tβ4 group. The cell viability of cultured corneal epithelial cells was examined by MTT assay. TUNEL staining was used to detect the apoptotic cells. ROS levels were estimated by DCFH-DA using fluorescent microscopy. Cell migration was measured using the scratch wound technique. Data were analyzed using one-way analysis of variance (ANOVA) and secondary analysis for significance with post Hoc tests.

RESULTS

The morphology of cultured cells was round, ovoid, polygonal or paving stone appearance. The results of RT-PCR showed that cultured corneal epithelial cells expressed both keratin 12 and connexin 43, the characteristic genes of corneal epithelial cells. The cell viability in H2O2 group was significantly reduced than that in control group (67.20% ± 5.87% vs. 100.00% ± 9.99%, P = 0.000); the cell viability was significantly improved in Tβ4+ H2O2 group than that in H2O2 group (83.42% ± 7.23% vs. 67.20% ± 5.87%, P = 0.023) . Cell migration was significantly increased in Tβ4 group compared with the controls (117.6% ± 2.22% vs. 100.00% ± 4.06%, P = 0.005) ; Compared with H2O2 group, cell migration was significant increase in H2O2 + Tβ4 group (96.57% ± 8.22% vs. 64.38% ± 11.08%, P = 0.000) . Compared with the control group, the intracellular ROS level of the H2O2 group was significantly increased (234.42% ± 22.15% vs. 100.00% ± 5.28%, P = 0.000) . Intracellular ROS level of H2O2+Tβ4 group was significantly decreased as compared with the H2O2 group (163.26% ± 10.53% vs. 234.42% ± 22.15%, P = 0.000). TUNEL staining indicated that Tβ4 treatment markedly inhibited H2O2-induced apoptosis in cultured corneal epithelial cells.

CONCLUSIONS

Tβ4 has a strong protection effect against oxidative damage induced by H2O2 in corneal epithelial cells through promoting cell growth and cell migration, and the underlying mechanisms may due to the antioxidation and anti-apoptotic effects of Tβ4.

Mechanical effects on KATP channel gating in rat ventricular myocytes

Cardiac K_ATP channels link metabolism with electrical activity. They are implicated in arrhythmias, secretion of atrial natriuretic peptide and protection of the heart from hypertrophy and failure. These processes may involve mechanosensitivity. K_ATP channels can be activated by mechanical stimulation and disrupting the cortical actin increases the activity. We propose that K_ATP channels are modulated by local bilayer tension and this tension is affected by cortical F-actin. Here we measured K_ATP background activity and stretch sensitivity with inside-out patches of rat ventricular myocytes before and after disrupting F-actin. Disrupting F-actin potentiated background activity but did not influence the slope sensitivity in the semilog relationship of NP_o vs. suction that is a measure of the change in dimensions between closed and open states. Thus actin alters prestress on the channel probably by parallel elastic sharing of mean cortical tension with the bilayer.

Thymosin beta 4 protects cardiomyocytes from oxidative stress by targeting anti-oxidative enzymes and anti-apoptotic genes

Background

Thymosin beta-4 (Tβ4) is a ubiquitous protein with many properties relating to cell proliferation and differentiation that promotes wound healing and modulates inflammatory mediators. The mechanism by which Tβ4 modulates cardiac protection under oxidative stress is not known. The purpose of this study is to dissect the cardioprotective mechanism of Tβ4 on H₂O₂ induced cardiac damage.

Methods

Rat neonatal cardiomyocytes with or without Tβ4 pretreatment were exposed to H₂O₂ and expression of antioxidant, apoptotic, and anti-inflammatory genes was evaluated by quantitative real-time PCR and western blotting. ROS levels were estimated by DCF-DA using fluorescent microscopy and fluorimetry. Selected antioxidant, anti-inflammatory and antiapoptotic genes were silenced by siRNA transfections in neonatal cardiomyocytes and effect of Tβ4 on H₂O₂-induced cardiac damage was evaluated.

Results

Pre-treatment of Tβ4 resulted in reduction of the intracellular ROS levels induced by H₂O₂ in cardiomyocytes. Tβ4 pretreatment also resulted in an increase in the expression of antiapoptotic proteins and reduction of Bax/BCl₂ ratio in the cardiomyocytes. Pretreatment with Tβ4 resulted in stimulating the expression of antioxidant enzymes copper/zinc SOD and catalase in cardiomyocytes at both transcription and translation levels. Tβ4 treatment resulted in the increased expression of anti-apoptotic and anti-inflammatory genes. Silencing of Cu/Zn SOD and catalase gene resulted in apoptotic cell death in the cardiomyocytes which was prevented by treatment with Tβ4.

Conclusion

This is the first report that demonstrates the effect of Tβ4 on cardiomyocytes and its capability to selectively upregulate anti-oxidative enzymes, anti-inflammatory genes, and antiapoptotic enzymes in the neonatal cardiomyocytes thus preventing cell death thereby protecting the myocardium. Tβ4 treatment resulted in decreased oxidative stress and inflammation in the myocardium under oxidative stress.

Controlled release of thymosin β4 from injected collagen-chitosan hydrogels promotes angiogenesis and prevents tissue loss after myocardial infarction

AIMS

Acute myocardial infarction (MI) leads to fibrosis and severe left ventricular wall thinning. Enhancing vascularization within the infarct reduces cell death and maintains a thick left ventricular wall, which is essential for proper cardiac function. Here, we evaluated the controlled delivery of thymosin β4 (Tβ4), which supports cardiomyocyte survival by inducing vascularization and upregulating Akt activity, in the treatment of MI.

MATERIALS & METHODS

We injected collagen-chitosan hydrogel with controlled release of Tβ4 into the infarct after performing left anterior descending artery ligation in rats.

RESULTS

Tβ4-encapsulated hydrogel (thymosin) significantly reduced tissue loss post-MI (13 ± 4%), compared with 58 ± 3% and 30 ± 8% tissue loss for no treatment (MI only) and Tβ4-free hydrogel (control). Significantly more Factor VIII-positive blood vessels with diameter >50 µm were in the thymosin group compared with both MI only and control (p < 0.0001), showing Tβ4-induced vascularization. Wall thickness was positively correlated with the mature blood vessel density (r = 0.9319; p < 0.0001).

CONCLUSION

Controlled release of Tβ4 within the infarct enhances angiogenesis and presence of cardiomyocytes that are necessary for cardiac repair.

Neuroprotective and neurorestorative effects of thymosin β4 treatment initiated 6 hours after traumatic brain injury in rats

OBJECT

Thymosin β4 (Tβ4) is a regenerative multifunctional peptide. The aim of this study was to test the hypothesis that Tβ4 treatment initiated 6 hours postinjury reduces brain damage and improves functional recovery in rats subjected to traumatic brain injury (TBI).

METHODS

Traumatic brain injury was induced by controlled cortical impact over the left parietal cortex in young adult male Wistar rats. The rats were randomly divided into the following groups: 1) saline group (n = 7); 2) 6 mg/kg Tβ4 group (n = 8); and 3) 30 mg/kg Tβ4 group (n = 8). Thymosin β4 or saline was administered intraperitoneally starting at 6 hours postinjury and again at 24 and 48 hours. An additional group of 6 animals underwent surgery without TBI (sham-injury group). Sensorimotor function and spatial learning were assessed using the modified Neurological Severity Score and the Morris water maze test, respectively. Animals were euthanized 35 days after injury, and brain sections were processed to assess lesion volume, hippocampal cell loss, cell proliferation, and neurogenesis after Tβ4 treatment.

RESULTS

Compared with saline administration, Tβ4 treatment initiated 6 hours postinjury significantly improved sensorimotor functional recovery and spatial learning, reduced cortical lesion volume and hippocampal cell loss, and enhanced cell proliferation and neurogenesis in the injured hippocampus. The high dose of Tβ4 showed better beneficial effects compared with the low-dose treatment.

CONCLUSIONS

Thymosin β4 treatment initiated 6 hours postinjury provides both neuroprotection and neurorestoration after TBI, indicating that Tβ4 has promising therapeutic potential in patients with TBI. These data warrant further investigation of the optimal dose and therapeutic window of Tβ4 treatment for TBI and the associated underlying mechanisms.