Preclinical
This study investigated whether two peptides derived from Thymosin β4 (Tβ4) — TB500 and Ac-SDKP — could reduce Alzheimer's disease (AD)-related pathology using both cell-based and animal models. In vitro, the peptides were tested in Aβ25-35-treated HT22 neuronal cells and primary cortical neurons, where they were found to reduce neurite atrophy, restore cell viability, and modulate apoptosis-related gene expression. In BV2 microglia, the peptides suppressed LPS-induced nitric oxide production, reduced pro-inflammatory cytokines, and inhibited M1 microglial polarization. In the 5×FAD transgenic mouse model of AD, treated animals showed improved performance on the Morris water maze and novel object recognition tests compared to untreated counterparts. Immunohistochemical analyses indicated reduced glial activation and neuronal apoptosis in treated mice, along with restored axonal density in the perirhinal cortex. However, hippocampal amyloid-β plaque burden was not significantly changed. Transcriptomic profiling highlighted genes such as Foxb2 and Or2k2 as potentially relevant to the observed neuroprotective effects. Key limitations include the exclusive use of preclinical models (no human data), reliance on a single transgenic mouse strain, and the need for further mechanistic validation. No human trials were conducted.
International immunopharmacology · Dec 2025DOI ↗ Preclinical
This study investigated the role of mast cell (MC)-derived thymosin β4 (Tβ4) in stress-induced intestinal barrier dysfunction in irritable bowel syndrome (IBS). Researchers measured Tβ4 levels in colonic mucus of IBS patients and used a combination of in vitro experiments, rodent models (including Tβ4-knockout rats and MC-deficient mice), and reconstitution experiments to examine mechanisms. The study found that Tβ4 levels were elevated in the colonic mucosa and intestinal MCs of IBS patients. In animal models, Tβ4 appeared to reduce tight junction proteins and the IL22RA1/Reg3γ cascade while increasing myosin light chain kinase activity, collectively impairing the epithelial barrier. Tβ4-deficient rats showed resistance to stress-induced barrier disruption, and reintroduction of Tβ4 or wild-type peritoneal MCs restored that disruption. Mechanistically, Tβ4 release from MCs was found to depend on corticotropin-releasing hormone receptor 1 signaling rather than classic degranulation, and its barrier-impairing effects were linked to inhibition of the IL22RA1/JAK1/STAT3 signaling pathway. Limitations include reliance on rodent models for mechanistic work, modest human clinical data, and the complexity of translating these findings to therapeutic applications.
World journal of gastroenterology · Nov 2025DOI ↗ Preclinical
This study investigated the role of Thymosin β4 (Tβ4) in breast cancer progression and its molecular mechanism. The researchers found that Tβ4 is significantly overexpressed in breast cancer tissues and cell lines, with high expression correlating with poorer clinical outcomes. Using functional experiments, the study showed that elevated Tβ4 promotes cancer cell proliferation, migration, epithelial-mesenchymal transition (EMT), and angiogenesis, while inhibiting apoptosis. Mechanistically, the study identified that Tβ4 directly regulates SLC7A11, a cystine/glutamate antiporter, which in turn enhances glutathione biosynthesis and suppresses lipid peroxidation — effectively inhibiting ferroptosis (an iron-dependent form of programmed cell death). Rescue experiments, conducted both in cell cultures (in vitro) and animal models (in vivo), demonstrated that silencing SLC7A11 reversed the cancer-promoting effects of Tβ4. The study concludes that a novel Tβ4/SLC7A11 signaling axis modulates ferroptosis resistance and contributes to breast cancer malignancy. Limitations include reliance on preclinical models, and no human clinical trials were conducted, leaving the translational relevance to patients yet to be established.
Cellular signalling · Sep 2025DOI ↗ Preclinical
This study investigated whether thymosin beta 4 (Tβ4), encoded by the gene TMSB4X, plays a role in Alzheimer's disease (AD) pathology and could serve as a potential intervention target. Researchers generated cerebral organoids ("mini-brains") from induced pluripotent stem cells (iPSCs) carrying familial AD (fAD)-associated mutations in the amyloid precursor protein (APP) gene. Using these organoids, they characterized dynamic changes in cellular states and found that mature neuron formation was markedly reduced in fAD organoids compared to healthy controls, alongside increased cellular senescence and beta-amyloid (Aβ) production. Notably, TMSB4X/Tβ4 expression was significantly decreased both in fAD organoid neurons and in excitatory neurons from post-mortem AD patient brain data. Treatment with Tβ4 protein appeared to rescue neurodevelopmental deficits and reduce Aβ formation in the fAD organoids. Corroborating findings were also reported in 5xFAD transgenic mice. The study concludes that Tβ4 may act as a neuroprotective factor capable of mitigating altered neurogenesis and AD pathology. Key limitations include the use of organoid and animal models rather than human clinical data, and the inherent complexity of translating organoid findings to human disease.
Stem cell reports · Aug 2025DOI ↗ Preclinical
This study investigated the biological activities of Ac-Tβ1-17, a novel acetylated peptide metabolite derived from the first 17 amino acids of thymosin β4 (Tβ4), with applications in regenerative biomaterials. Researchers first assessed its antiviral potential, finding that Ac-Tβ1-17 demonstrated protease inhibition activity against SARS-CoV-2 that reportedly exceeded that of its parent protein. In human umbilical vein endothelial cells (HUVECs), the peptide was associated with enhanced cell proliferation, wound healing, and reactive oxygen species (ROS) scavenging. The study also incorporated Ac-Tβ1-17 into a peptide-based scaffold, where it appeared to support cell growth and angiogenesis both within the scaffold and through gradual release. Mechanistically, treatment upregulated gene expression of Akt, ERK, PI3K, MEK, and Bcl-2, along with proangiogenic proteins. Ex vivo experiments in mouse fetal metatarsal tissue further suggested enhanced tissue growth and angiogenesis. Limitations include the predominantly in vitro and ex vivo design with no human clinical data, a small-animal ex vivo model, and the absence of controlled in vivo studies. The findings are exploratory and suggest Ac-Tβ1-17 as a candidate biomaterial-active peptide warranting further investigation.
Bioactive materials · Mar 2025DOI ↗ Preclinical
This study investigated the role of plasmacytoid dendritic cells (pDCs) during the active effector phase of allergic asthma, moving beyond their previously known role in immune tolerance. Using BDCA2-DTR transgenic mice in which pDCs can be selectively depleted with diphtheria toxin, researchers sensitized and challenged animals with house dust mite allergen. They found that pDC depletion worsened asthmatic inflammation by increasing CCR2-dependent recruitment of inflammatory monocyte-derived cells. RNA sequencing of lung pDCs revealed that the small anti-inflammatory peptide thymosin β4 (Tβ4) was among the most upregulated genes in asthmatic conditions. IL-33 released by airway epithelial cells was found to drive Tβ4 expression in pDCs, which represented the dominant pulmonary source of Tβ4. Mechanistically, Tβ4 suppressed IL-4/IL-13-induced JAK1/STAT6/EGR2 signaling in alveolar macrophages, reducing CCL2 production and monocyte recruitment. Tβ4 supplementation reversed disease exacerbation in pDC-depleted mice. Notably, reduced serum Tβ4 levels were observed in both asthmatic mice and a human cohort with active allergic asthma. Limitations include the predominantly murine mechanistic data and a small, cross-sectional human serum dataset that limits causal interpretation in humans.
The Journal of allergy and clinical immunology · Feb 2025DOI ↗ Preclinical
This study developed and validated a simultaneous analytical method using ultra-high-performance liquid chromatography coupled with high-resolution Orbitrap mass spectrometry (UHPLC-Q-Exactive MS/MS) to quantify TB-500 (Ac-LKKTETQ), a synthetic peptide derived from the active site of thymosin β4 (Tβ4), alongside its metabolites. Metabolism was studied in human serum, multiple in-vitro enzyme systems, and rat urine samples following TB-500 administration. Researchers synthesized authentic standards of the metabolites to enable structural identification. Key findings included that Ac-LK was the predominant short-term metabolite (0–6 hours), while Ac-LKK was detectable as a longer-term metabolite up to 72 hours. In fibroblast cell culture experiments, neither TB-500 nor its metabolites demonstrated cytotoxicity. Notably, among all compounds tested, only the metabolite Ac-LKKTE showed statistically significant wound-healing activity compared to controls, leading the authors to suggest that previously reported wound-healing effects attributed to TB-500 in the literature may actually be mediated by this metabolite rather than the parent peptide. Limitations include that biological activity testing was confined to cell-based assays, and no human pharmacokinetic or efficacy data were generated.
Journal of chromatography. B, Analytical technologies in the biomedical and life sciences · Feb 2024DOI ↗