Intravenous mesenchymal stromal cell therapy for inflammatory bowel disease: Lessons from the acute graft versus host disease experience

Serum-Free Medium Enhances the Therapeutic Effects of Umbilical Cord Mesenchymal Stromal Cells on a Murine Model for Acute Colitis

The usage of animal serum may ultimately prevent the application of ex vivo cultured mesenchymal stromal cells (MSCs) in a clinical setting due to safety concerns and batch-to-batch variability. Increasing regulatory pressure to limit use of animal serum has been issued and serum-free, xeno-free, and chemically defined media (S&XFM-CD) is encouraged to replace serum-containing media (SCM) in the stem cell preparation process. We previously developed a S&XFM-CD for the expansion of umbilical cord-derived MSCs (UCMSCs). Different culture conditions affect the function of MSCs, which may further affect the therapeutic efficiency and mechanisms of action. In this study, we compared the therapeutic effect and mechanism of UCMSCs in S&XFM-CD (UCMSC^S&XFM−CD) in experimental colitis with those in SCM (UCMSC^SCM). UCMSC^S&XFM−CD exhibited better therapeutic effects than UCMSC^SCM by body weight, disease activity index, and histological colitis score. UCMSC^S&XFM−CD or UCMSC^SCM migrated to the inflammation site of injured colon, but exhibited low levels of recruitment and persistence. Systemic depletion of endogenous macrophages impaired the therapeutic effects of UCMSC^SCM and UCMSC^S&XFM−CD. Furthermore, UCMSC^S&XFM−CD more markedly promoted intestinal macrophage polarisation from M1 to M2 phenotype to produce higher levels of IL-10 and lower levels of TNF-α in colon tissue than UCMSC^SCM, while a higher level of IL-4 was produced in UCMSC^SCM-treated group. UCMSC^S&XFM−CD cocultured with RAW264.7 cells in a transwell system promoted the release of TSG-6 and IL-6, whereas UCMSC^SCM increased PGE₂ levels. Taken together, we demonstrated that UCMSCs in S&XFM-CD exhibited improved therapeutic effects with altered cytokine secretion in an experimental acute colitis model.

MiR-920 promotes osteogenic differentiation of human bone mesenchymal stem cells by targeting HOXA7

Background

To explore the effect of miR-920 on osteogenic differentiation of human bone mesenchymal stem cells (hBMSCs) and the possible mechanism.

Methods

Osteoporosis (OP) and healthy control bone tissues were collected, and the relative expression of miR-920 and HOXA7 was measured. hBMSCs were isolated and cultured in vitro. Alkaline phosphatase activity and miR-920 and HOXA7 relative expression were measured during osteogenic differentiation of hBMSCs. Then, bioinformatic analysis was performed to assess the potential mechanism of miR-920. MiR-920 mimic and inhibitor were introduced into hBMSCs by lipofection transfection and were used to investigate the effect of miR-920 on the osteogenic differentiation of hBMSCs. A dual luciferase reporter assay was used to identify whether the 3′UTR of HOXA7 mRNA was a direct target of miR-920. Western blotting was performed to assess whether miR-920 affected the MAPK signaling pathway.

Results

We found that miR-920 was downregulated in OP patients compared with controls, while HOXA7 was upregulated, and miR-920 had a negative correlation with HOXA7 (r = − 0.859, P = 0.001). Moreover, miR-920 was increased during osteogenic differentiation of hBMSCs, while HOXA7 had the opposite tendency. Bioinformatic analysis revealed that there were a total of 207 target genes, and MAPK was a potential targeted signaling pathway. MiR-920 mimic significantly increased ALP activity, calcium deposition, osteoblastic protein expression (ALP and OSX), and p-p38 and p-JNK protein levels.

Conclusion

Overall, miR-920 promotes osteogenic differentiation of hBMSCs by targeting HOXA7 through the MAPK signaling pathway.

The therapeutic role of bone marrow stem cell local injection in rat experimental periodontitis

Mesenchymal stem cell therapy brings hope for regenerating damaged periodontal tissues. The present study aimed to investigate the therapeutic role of local bone marrow stem cell (BMSC) injection in ligation-induced periodontitis and the underlying mechanisms. Alveolar bone lesion was induced by placing ligatures subgingivally around the bilateral maxillary second molars for 28 days. The alveolar bone lesion was confirmed by micro-CT analysis and bone histomorphometry. Allogeneic BMSC transplantation was carried out at 28 day after ligation. The survival state of the transplanted BMSC was observed by bioluminescent imaging. The implantation of the BMSC into the gingival tissues and periodontal ligament was confirmed by green fluorescent protein (GFP) immunohistochemical staining. The expression level of pro-inflammatory, tumour necrosis factor-α (TNF-α) and interleukin-1β (IL-1β), and receptor activator of nuclear factor-κ B ligand (RANKL) and osteoprotegerin (OPG) in periodontal tissues were evaluated by immunohistochemical staining and real-time PCR. Significant reverse of alveolar bone lesion was observed after BMSC transplantation. The expression of TNF-α and IL-1β was down-regulated by BMSC transplantation. The number of tartrate-resistant acid phosphatase (TRAP)-positive osteoclasts in the periodontal ligament was reduced, and the increased RANKL expression and decreased OPG expression were also reversed after BMSC transplantation. It is concluded that allogeneic BMSC local injection could inhibit the inflammation of the periodontitis tissue and promote periodontal tissue regeneration.

Cancer-associated fibroblasts in gastrointestinal cancer

The tumour microenvironment, also termed the tumour stroma or tumour mesenchyme, includes fibroblasts, immune cells, blood vessels and the extracellular matrix and substantially influences the initiation, growth and dissemination of gastrointestinal cancer. Cancer-associated fibroblasts (CAFs) are one of the critical components of the tumour mesenchyme and not only provide physical support for epithelial cells but also are key functional regulators in cancer, promoting and retarding tumorigenesis in a context-dependent manner. In this Review, we outline the emerging understanding of gastrointestinal CAFs with a particular emphasis on their origin and heterogeneity, as well as their function in cancer cell proliferation, tumour immunity, angiogenesis, extracellular matrix remodelling and drug resistance. Moreover, we discuss the clinical implications of CAFs as biomarkers and potential targets for prevention and treatment of patients with gastrointestinal cancer.

Anti-PD-1-induced high-grade hepatitis associated with corticosteroid-resistant T cells: a case report

Effective treatment or prevention of immune side effects associated with checkpoint inhibitor therapy of cancer is an important goal in this new era of immunotherapy. Hepatitis due to immunotherapy with antibodies against PD-1 is uncommon and generally of low severity. We present an unusually severe case arising in a melanoma patient after more than 6 months uncomplicated treatment with anti-PD-1 in an adjuvant setting. The hepatitis rapidly developed resistance to high-dose steroids, requiring anti-thymocyte globulin (ATG) to achieve control. Mass cytometry allowed comprehensive phenotyping of circulating lymphocytes and revealed that CD4⁺ T cells were profoundly depleted by ATG, while CD8⁺ T cells, B cells, NK cells and monocytes were relatively spared. Multiple abnormalities in CD4⁺ T cell phenotype were stably present in the patient before disease onset. These included a population of CCR4⁻CCR6⁻ effector/memory CD4⁺ T cells expressing intermediate levels of the Th1-related chemokine receptor CXCR3 and abnormally high multi-drug resistance type 1 transporter (MDR1) activity as assessed by a rhodamine 123 excretion assay. Expression of MDR1 has been implicated in steroid resistance and may have contributed to the severity and lack of a sustained steroid response in this patient. The number of CD4⁺ rhodamine 123-excreting cells was reduced > 3.5-fold after steroid and ATG treatment. This case illustrates the need to consider this form of steroid resistance in patients failing treatment with corticosteroids. It also highlights the need for both better identification of patients at risk and the development of treatments that involve more specific immune suppression.