Berberine enhances the function of intestinal stem cells in healthy and radiation-injured mice.

Intestinal stem cells (ISCs) are pivotal for the maintenance and regeneration of the intestinal epithelium. Berberine (BBR) exhibits diverse biological activities, but it remains unclear whether BBR can modulate ISCs' function. Therefore, we investigated the effects of BBR on ISCs in healthy and radiation-injured mice and explored the potential underlying mechanisms involved. The results showed that BBR significantly increased the length of the small intestines, the height of the villi, and the depth and density of the crypts, promoted the proliferation of cryptal epithelial cells and increased the number of OLFM4+ ISCs and goblet cells. Crypts from the BBR-treated mice were more capable of growing into enteroids than those from untreated mice. BBR alleviated WAI-induced intestinal injury. BBR suppressed the apoptosis of crypt epithelial cells, increased the quantity of goblet cells, and increased the quantity of OLFM4+ ISCs and tdTomato+ progenies of ISCs after 8 Gy WAI-induced injury. Mechanistically, BBR treatment caused a significant increase in the quantity of p-S6, p-STAT3 and p-ERK1/2 positive cryptal epithelial cells under physiological conditions and after WAI-induced injury. In conclusion, BBR is capable of enhancing the function of ISCs either physiologically or after radiation-induced injury, indicating that BBR has potential value in the treatment of radiation-induced intestinal injury.

Stereotactic ablative radiotherapy and FAPα-based cancer vaccine suppresses metastatic tumor growth in 4T1 mouse breast cancer.

BACKGROUND AND PURPOSE: This study tested the hypothesis that a novel combination of stereotactic ablation radiotherapy (SABR) and a cancer vaccine against fibroblast activation protein-alpha (FAPα) can suppress established tumor growth and impede potential metastasis. METHODS: The poorly immunogenic metastatic mouse mammary carcinoma 4T1 was used as a model. Mice were randomly assigned to five treatment groups: (1) untreated control, (2) FAPα-based cancer vaccine, (3) SABR, (4) SABR + pCDH (lentiviral control vector), (5) SABR + FAPα-based cancer vaccine (SABR/FAPα-Vax). FAPα-based cancer vaccine were administered subcutaneously every week for a total of three treatments. SABR was delivered to the primary tumor by 3 × 8 Gy after the first vaccination. RESULTS: Consistent with the poorly immunogenic nature of 4T1, tumor-bearing mice receiving FAPα-based cancer vaccine or SABR monotherapy showed a modest reduction in tumor volume and increased animal lifespan. In contrast, SABR/FAPα-Vax was well-tolerated, significantly reduced tumor burden, and increased survival compared to monotherapy. The increased survival correlated with inhibition of extracellular matrix (ECM) production, tumor vascularization and lymphangiogenesis. SABR/FAPα-Vax also resulted in an abscopal effect capable of eliminating lung metastases. SABR/FAPα-Vax recruited and activated CD8 + T cells to attack tumor cells and FAPα + stromal cells, and initiated suppressor cell reprogramming, including facilitating macrophage polarization toward an anti-tumor (M1) state, as well as depleting myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Tregs). CONCLUSION: These findings provide a novel therapeutic combination of radiation and FAPα-based cancer vaccine with promising results against poorly immunogenic metastatic cancer. This study may pave the way to overcome the therapeutic resistance caused by FAPα + CAFs.

Mesenchymal Stem Cell-Derived Extracellular Vesicles Attenuate Radiation-Induced Lung Injury via miRNA-214-3p.

Aims: Radiotherapy is an effective treatment for thoracic malignancies, but it can cause pulmonary injury and may lead to respiratory failure in a subset of patients. Extracellular vesicles (EVs) derived from mesenchymal stem cells (MSCs) are now recognized as a new candidate for cell-free treatment of lung diseases. Here, we investigated whether MSC-derived EVs (MSC-EVs) could ameliorate radiation-induced lung injury. Results: We exposed mice to thoracic radiation with a total dose of 15 Gy and assessed the protective effects of MSC-EVs on endothelial cells damage, vascular permeability, inflammation, and fibrosis. We found that MSC-EVs attenuated radiation-induced lung vascular damage, inflammation, and fibrosis. Moreover, MSC-EVs reduced the levels of radiation-induced DNA damage by downregulating ATM/P53/P21 signaling. Our results confirmed that the downregulation of ataxia telangiectasia mutated (ATM) was regulated by miR-214-3p, which was enriched in MSC-EVs. Further analysis demonstrated that MSC-EVs inhibited the senescence-associated secretory phenotype development and attenuated the radiation-induced injury of endothelial cells. Innovation and Conclusion: Our study reveals that MSC-EVs can reduce pulmonary radiation injury through transferring miR-214-3p, providing new avenues to minimize lung injury from radiation therapy. Antioxid. Redox Signal. 35, 849-862.

Self-assembled GFFYK peptide hydrogel enhances the therapeutic efficacy of mesenchymal stem cells in a mouse hindlimb ischemia model.

Mesenchymal stem cell (MSC) transplantation has emerged as a very promising strategy for the treatments of peripheral artery disease (PAD). However, MSC-based therapies are limited by low cell retention and survival rate in the ischemic zone. Small molecular (SM) hydrogels have shown attractive abilities to enhance the therapeutic effects of human MSCs via promoting their proliferation or maintaining their differentiation potential. Here, we designed and synthesized a new bioactive and biocompatible hydrogel, Nap-GFFYK-Thiol, using disulfide bonds as cleavable linkers to control the molecular self-assembly and we hypothesized this hydrogel could enhance the retention and engraftment of human placenta-derived MSCs (hP-MSCs) in a mouse ischemic hindlimb model. In vitro results demonstrated that the Nap-GFFYK-Thiol hydrogel increased cell viability through paracrine effects. Moreover, it enhanced the proangiogenic and anti-apoptotic effects of hP-MSCs. In vivo, Nap-GFFYK-Thiol hydrogel improved the hP-MSC retention in the murine ischemic hindlimb model as visualized by bioluminescence imaging. Furthermore, cotransplantation of hP-MSCs with hydrogel improved blood perfusion, leading to superior limb salvage. These therapeutic effects may attribute to reduced inflammatory cell infiltration, enhanced angiogenesis as well as suppressed collagen deposition. In conclusion, the Nap-GFFYK-Thiol hydrogel fabricated using disulfide bonds as cleavable linkers serves as an artificial niche for promoting hP-MSC survival and proangiogenic factor secretion in PAD therapy and thereby provide an alternative strategy for PAD therapy. STATEMENT OF SIGNIFICANCE: Although several phase I/II clinical trials of MSC-based treatments for critical limb ischemia (CLI) are ongoing, MSC-based therapies are still challenged by the low quality and quantity of cells in the ischemic zone, especially in cases of extensive or irreversible damage. Hydrogels have favorable biocompatibility and safety records in the medical field. In the current study, we engineered a new bioactive and biocompatible hydrogel, Nap-GFFYK-Thiol, using disulfide bonds as cleavable linkers to enhance the therapeutic efficacy of human placenta-derived MSCs (hP-MSCs) in mouse limb ischemia model. Notably, Nap-GFFYK-Thiol hydrogel acts as an artificial niche for promoting hP-MSC survival and proangiogenic factor secretion in PAD therapy, which further promoted the restoration of blood perfusion and regeneration of muscle cells. Considering the proangiogenic effect of Nap-GFFYK-Thiol on hP-MSCs, our results may provide a new strategy for the treatment of PAD.

MSCs inhibit tumor progression and enhance radiosensitivity of breast cancer cells by down-regulating Stat3 signaling pathway.

The acquisition of radioresistance by breast cancer cells during radiotherapy may lead to cancer recurrence and poor survival. Signal transducer and activator of transcription 3 (Stat3) is activated in breast cancer cells and, therefore, may be an effective target for overcoming therapeutic resistance. Mesenchymal stem cells (MSCs) have been investigated for use in cancer treatment. Here, we investigated the potential of MSC conditioned medium (MSC-CM) in sensitizing breast cancer to radiotherapy. It was found that MSC-CM could inhibit the level of activated Stat3, suppress cancer growth, and exhibit synergetic effects with radiation treatment in vitro and in vivo. Furthermore, MSC-CM reduced the ALDH-positive cancer stem cells (CSCs) population, modulated several potential stem cell markers, and decreased tumor migration, as well as metastasis. These results demonstrate that MSC-CM suppresses breast cancer cells growth and sensitizes cancer cells to radiotherapy through inhibition of the Stat3 signaling pathway, thus, providing a novel strategy for breast cancer therapy by overcoming radioresistance.

Down-regulation of interleukin 7 receptor (IL-7R) contributes to central nervous system demyelination.

Interleukin 7 receptor (IL-7R) has been associated with the pathogenesis of multiple sclerosis (MS), though the mechanisms are not clear. Because myelin expression is highly conserved between zebrafish and mammals, zebrafish have become an ideal model for studying demyelination. We used a transgenic (Tg; mbp:nfsB-egfp) zebrafish line in which oligodendrocytes expressed green fluorescent protein (GFP) from the larval stage to adulthood. Exposing adult transgenic zebrafish to metronidazole induced demyelination that resembled the morphological changes associated with the early stages of MS. The metronidazole-induced demyelination was confirmed by magnetic resonance imaging (MRI) for the first time. Microarray analysis revealed down-regulation of IL-7R during demyelination. Targeted knockdown of IL-7R demonstrated that IL-7R is essential for myelination in embryonic and larval zebrafish. Moreover, IL-7R down-regulation induced signaling via the JAK/STAT pathway leading to apoptosis in oligodendrocytes. These findings contribute to our understanding of the role of IL-7R in demyelination, and provide a rationale for the development of IL-7R-based therapies for MS and other demyelinating diseases.

Role of tumor necrosis factor-alpha in zebrafish retinal neurogenesis and myelination.

AIM: To investigate the role of tumor necrosis factor-alpha (TNF-α) in zebrafish retinal development and myelination. METHODS: Morpholino oligonucleotides (MO), which are complementary to the translation start site of the wild-type embryonic zebrafish TNF-α mRNA sequence, were synthesized and injected into one- to four-cell embryos. The translation blocking specificity was verified by Western blotting using an anti-TNF-α antibody, whole-mount in situ hybridization using a hepatocyte-specific mRNA probe ceruloplasmin (cp), and co-injection of TNF-α MO and TNF-α mRNA. An atonal homolog 7 (atoh7) mRNA probe was used to detect neurogenesis onset. The retinal neurodifferentiation was analyzed by immunohistochemistry using antibodies Zn12, Zpr1, and Zpr3 to label ganglion cells, cones, and rods, respectively. Myelin basic protein (mbp) was used as a marker to track and observe the myelination using whole-mount in situ hybridization. RESULTS: Targeted knockdown of TNF-α resulted in specific suppression of TNF-α expression and a severely underdeveloped liver. The co-injection of TNF-α MO and mRNA rescued the liver development. Retinal neurogenesis in TNF-α morphants was initiated on time. The retina was fully laminated, while ganglion cells, cones, and rods were well differentiated at 72 hours post-fertilization (hpf). mbp was expressed in Schwann cells in the lateral line nerves and cranial nerves from 3 days post-fertilization (dpf) as well as in oligodendrocytes linearly along the hindbrain bundles and the spinal cord from 4 dpf, which closely resembled its endogenous profile. CONCLUSION: TNF-α is not an essential regulator for retinal neurogenesis and optic myelination.