Fig 2: sh-Chi3l1-MSCs promote IL-17A production in aGvHD mice. (a, b) Lymphocytes were obtained from the spleens of aGvHD mice on day 14 after hUC-MSC, sh-Chi3l1-MSC, sh-NC-MSC (1 × 106), or PBS (0.2 ml) treatment. Intracellular cytokines in lymphocytes were measured by flow cytometry. (a) IFN-γ and IL-17A were analyzed by flow cytometry. (b) The proportion of intracellular cytokines IFN-γ and IL-17A was measured in different groups. (c) Serum IFN-γ and IL-17A were measured by ELISA (n = 8, three independent experiments, one-way ANOVA, and Tukey's multiple comparison test, ∗P < 0.05; ∗∗P < 0.01; ns: not significant). IFN-γ: interferon-gamma; IL-17A: interleukine-17A.

Fig 3: Chi3l1 deletion compromises hUC-MSCs and inhibits T cell proliferation. (a–c) CD3+ T cells obtained from the spleens of healthy C57BL/6J mice were stained with CFSE (5 μM) and then incubated in 24-well plates with hUC-MSCs, sh-Chi3l1-MSCs, and sh-NC-MSCs at a CD3+ T/hUC-MSC ratio of 20 : 1 for 72 hours. (a) Proliferation of CD3+ T cells analyzed by flow cytometry. (b) CD3+ T cell proliferation was measured after treatment with different hUC-MSCs. (c) mRNA expression levels of IFN-γ, IL-17A, and FOXP3 analyzed by qPCR (three independent experiments, one-way ANOVA, and Tukey's multiple comparison test, ∗∗P < 0.01; ns: not significant).

Fig 4: Chi3l1 deletion impairs the therapeutic effects of hUC-MSCs in aGvHD mice. (a–c) Recipient mice (BALB/C) were irradiated with a single dose of 800 cGy total body irradiation (Co60γ source) and intravenously injected with C57BL/6J bone marrow cells (1 × 107) plus splenocytes (1 × 107) to induce the aGvHD model. Two days after transplantation, different MSCs, including hUC-MSCs, sh-Chi3l1-MSCs, sh-NC-MSCs (1 × 106), or PBS, were injected intravenously into aGvHD mice. (a) Survival curves of each group of mice (control: n = 12, aGvHD, hUC-MSCs, sh-Chi3l1-MSCs, and sh-NC-MSCs: n = 20, log-rank test, ∗∗∗P < 0.001). (b) The clinical score of hUC-MSCs, sh-Chi3l1-MSCs, sh-NC-MSCs, or PBS groups of mice. ∗P < 0.05; ∗∗P < 0.01; ns: not significant. (c) Hematoxylin and eosin staining was used to analyze the histological and pathological changes in the skin, intestine, and lung in aGvHD mice 21 days after hUC-MSCs, sh-Chi3l1-MSCs, sh-NC-MSCs, or PBS treatment. Scale bar: 200 μm, n = 7, three independent experiments. CTRL: healthy mice.

Fig 5: YKL‐40 and VEGF protein expression and ERK1/2 signaling are upregulated in mice with laser‐induced CNV. (A–B) The protein levels of YKL‐40 and VEGF in the neuroretinas of mice after laser photocoagulation. (C–D) The protein levels of YKL‐40 and VEGF in the RPE/choroid complex of mice after laser photocoagulation. (E–H) ERK1/2 phosphorylation levels were upregulated in the NR and RPE/choroid of mice subjected to laser photocoagulation. (Mean ± SEM; n = 4; one‐way ANOVA with Bonferroni correction). P < 0.05 denotes statistical significance, *P < 0.05, **P < 0.01, ***P < 0.001.