Journal: Bioactive Materials

Article Title: pH-neutralization strategy to suppress GPCR68 spatiotemporally activates T cells and enhances anti-tumor immunity

doi: 10.1016/j.bioactmat.2026.02.039

Figure Lengend Snippet: GPCR68 as a pH-Sensing regulator in T Cells and generation of GPCR68 fl/fl CD4 Cre mice. (A) Schematic diagram of the effect of pH on T cell GPCR68 as well as tumor. (B) Naïve CD4 + T cells were isolated and activated using anti-CD3 and anti-CD28 using the culture media with varying pH. RT-qPCR was performed to determine the expression of GPCR68 at various pH. (C) Naïve CD4 + T cells were activated with anti-CD3 and anti-CD28 under different pH conditions, and GPCR68 protein expression was assessed by Western blot analysis. (D) To generate conditional knockout (CKO) of GPCR68 in T cells, GPCR68 fl/fl mice were crossed with CD4 Cre mice and generated GPCR68 fl/fl CD4 Cre (CKO). (E) Flow cytometry was used to determine the population of CD4 and CD8 cells in the lymph nodes (LN), thymus (THY), and spleen (SP) at the basal level in CD4 Cre or GPCR68 fl/fl CD4 Cre mice. (F) Flow cytometry was used to determine the population of Foxp3+ Treg cells in the lymph nodes, thymus, and spleen at the basal level in the CD4 Cre or GPCR68 fl/fl CD4 Cre mice. (G-H) The population of F4/80+, CD11c+ (G), and B220+ (H) cells was determined in the lymph nodes and spleen at the basal level in the CD4 Cre or GPCR68 fl/fl CD4 Cre mice. (I-J) Flow cytometry was used to evaluate the CD4 + or CD8 + T cells for the determination of intracellular cytokines IFN-γ+ (I), or TNF-α+ (J) from the spleen and lymph nodes at basal level in the CD4 Cre or GPCR68 fl/fl CD4 Cre mice. Student t-test was performed for comparison between the two groups. Data are mean ± SEM (n = 5), ∗ p < 0.05.

Article Snippet: Naïve T cells were purified from lymph nodes as well as spleens of C57/BL6, CD4 Cre , GPCR68 fl/fl CD4 Cre (CKO) mice by using the mouse naïve CD4 + T Cell Isolation Kit (#130-104-453; Miltenyi Biotec) or naïve CD8 + T Cell Isolation Kit (#130-096-543; Miltenyi Biotec) for negative selection.

Techniques: Isolation, Quantitative RT-PCR, Expressing, Western Blot, Knock-Out, Generated, Flow Cytometry, Comparison

Journal: Bioactive Materials

Article Title: pH-neutralization strategy to suppress GPCR68 spatiotemporally activates T cells and enhances anti-tumor immunity

doi: 10.1016/j.bioactmat.2026.02.039

Figure Lengend Snippet: GPCR68 fl/fl CD4 Cre mice exhibit improved anti-tumor mmune responses. (A-C) Naïve CD4 + T cells were isolated from CD4 Cre or GPCR68 fl/fl CD4 Cre mice and activated using anti-CD3 and anti-CD28 using the culture media under physiologic neutral pH (7.4) or varying pH 6.0, 6.5, or 7.8. Flow cytometry plots showing the expression of IFN-γ and IL-2 in CD4 + T cells from CD4 Cre and GPCR68 fl/fl CD4 Cre mice. Each panel represents the frequency of IFN-γ + and IL-2 + cells. (B) Bar graph summarizing the percentage of IFN-γ + CD4 + T cells at each pH level for CD4 Cre and GPCR68 fl/fl CD4 Cre mice. (C) Bar graph showing the percentage of IL-2 + CD4 + T cells at each pH for CD4 Cre and GPCR68 fl/fl CD4 Cre mice. (D) Experimental timeline depicting tumor induction and treatment protocol in CD4 Cre and GPCR68 fl/fl CD4 Cre mice. (E) Tumor growth curves in CD4 Cre and GPCR68 fl/fl CD4 Cre mice. (F) Tumor weight in CD4 Cre versus GPCR68 fl/fl CD4 Cre mice at the time of harvesting on day 21. (G) Representative images of excised tumors at day 21. (H) Flow cytometric analysis of IFN-γ production by tumor-infiltrating CD4 + and CD8 + T cells. (I) Flow cytometric analysis of TNF-α production by tumor-infiltrating CD4 + and CD8 + T cells. Student t-test was performed for comparison between the two groups. Two-way ANOVA was used for multiple comparisons. Data are mean ± SEM (n = 5). ∗ p < 0.05, ∗∗ p < 0.01, ∗∗∗ p < 0.001, ns = not significant.

Article Snippet: Naïve T cells were purified from lymph nodes as well as spleens of C57/BL6, CD4 Cre , GPCR68 fl/fl CD4 Cre (CKO) mice by using the mouse naïve CD4 + T Cell Isolation Kit (#130-104-453; Miltenyi Biotec) or naïve CD8 + T Cell Isolation Kit (#130-096-543; Miltenyi Biotec) for negative selection.

Techniques: Isolation, Flow Cytometry, Expressing, Comparison

Journal: Bioactive Materials

Article Title: pH-neutralization strategy to suppress GPCR68 spatiotemporally activates T cells and enhances anti-tumor immunity

doi: 10.1016/j.bioactmat.2026.02.039

Figure Lengend Snippet: Physicochemical properties of BOLT, and BOLT reduces the growth of tumor cells. (A) Schematic of surface double-layer formation and ion release. (B) Negative zeta potential (−1.365 mV) and high conductivity (1.334 mS/cm), confirming colloidal stability and ion release. (C) Uniform particle size (∼1478 nm) across batches. (D) Interfacial pH buffering in PBS. (E) Naïve CD4 + T cells were isolated and activated using anti-CD3 and anti-CD28 using the culture media with 6.0 pH and treated with various doses of BOLT. RT-qPCR was performed to determine the expression of Gpcr68 at various BOLT doses in activated T cells at acidic pH. (F) Anti-CD3 and anti-CD28 activated CD4 + T cells were treated with different doses of BOLT to determine the protein expression of GPCR68 using Western blot. (G-J) CCK8 assay was performed to analyze the effect of various pH on B16, MC38, 143B, and MG63 cell proliferation. (K-L) Effect of various doses of BOLT on the B16 and K7M2 cell growth to determine the IC-50 of BOLT. Error bars represent mean ± SEM. ∗∗ p < 0.01 and ∗ p < 0.05.

Article Snippet: Naïve T cells were purified from lymph nodes as well as spleens of C57/BL6, CD4 Cre , GPCR68 fl/fl CD4 Cre (CKO) mice by using the mouse naïve CD4 + T Cell Isolation Kit (#130-104-453; Miltenyi Biotec) or naïve CD8 + T Cell Isolation Kit (#130-096-543; Miltenyi Biotec) for negative selection.

Techniques: Zeta Potential Analyzer, Isolation, Quantitative RT-PCR, Expressing, Western Blot, CCK-8 Assay

Journal: Bioactive Materials

Article Title: pH-neutralization strategy to suppress GPCR68 spatiotemporally activates T cells and enhances anti-tumor immunity

doi: 10.1016/j.bioactmat.2026.02.039

Figure Lengend Snippet: BOLT activates T cell PI3K-AKT-mTOR pathway to enhance T cell anti-tumor effect. (A) Flow cytometry plots compare IFN-γ and IL-2 expression at pH 7.8 and 6.0 along with various doses of BOLT in CD4 + T cells from CD4 Cre or GPCR68 fl/fl CD4 Cre mice. (B, C) Bar graphs show IFN-γ and IL-2 expression in CD4 + T cells from CD4 Cre or GPCR68 fl/fl CD4 Cre mice. (D) Naïve CD4 + T cells were activated with anti-CD3 and anti-CD28 antibodies and incubated for 3 days with cell culture media of different pH levels. Western blot was performed to determine the phosphorylation of Akt and S6 under acidic conditions (pH 6.5) and alkaline pH (7.8). (E) Activated CD4 + T cells were treated with 0, 0.25, and 0.5 mg/mL doses of BOLT following CD4 + T cells activation at pH 7.8. Western blot analysis showing the phosphorylation of Akt and S6 were observed. (F) CD4 + T cells were activated and treated with BOLT at acidic pH. Western blot analysis was performed to determine the phosphorylation of Akt and S6. Two-way ANOVA was used for multiple comparisons. Experiments were conducted in triplicate. Data are mean ± SEM, ∗ p < 0.05, ∗∗ p < 0.01, ∗∗∗ p < 0.001, and ∗∗∗∗ p < 0.0001.

Article Snippet: Naïve T cells were purified from lymph nodes as well as spleens of C57/BL6, CD4 Cre , GPCR68 fl/fl CD4 Cre (CKO) mice by using the mouse naïve CD4 + T Cell Isolation Kit (#130-104-453; Miltenyi Biotec) or naïve CD8 + T Cell Isolation Kit (#130-096-543; Miltenyi Biotec) for negative selection.

Techniques: Flow Cytometry, Expressing, Incubation, Cell Culture, Western Blot, Phospho-proteomics, Activation Assay

Journal: Bioactive Materials

Article Title: pH-neutralization strategy to suppress GPCR68 spatiotemporally activates T cells and enhances anti-tumor immunity

doi: 10.1016/j.bioactmat.2026.02.039

Figure Lengend Snippet: GPCR68 as a pH-Sensing regulator in T Cells and generation of GPCR68 fl/fl CD4 Cre mice. (A) Schematic diagram of the effect of pH on T cell GPCR68 as well as tumor. (B) Naïve CD4 + T cells were isolated and activated using anti-CD3 and anti-CD28 using the culture media with varying pH. RT-qPCR was performed to determine the expression of GPCR68 at various pH. (C) Naïve CD4 + T cells were activated with anti-CD3 and anti-CD28 under different pH conditions, and GPCR68 protein expression was assessed by Western blot analysis. (D) To generate conditional knockout (CKO) of GPCR68 in T cells, GPCR68 fl/fl mice were crossed with CD4 Cre mice and generated GPCR68 fl/fl CD4 Cre (CKO). (E) Flow cytometry was used to determine the population of CD4 and CD8 cells in the lymph nodes (LN), thymus (THY), and spleen (SP) at the basal level in CD4 Cre or GPCR68 fl/fl CD4 Cre mice. (F) Flow cytometry was used to determine the population of Foxp3+ Treg cells in the lymph nodes, thymus, and spleen at the basal level in the CD4 Cre or GPCR68 fl/fl CD4 Cre mice. (G-H) The population of F4/80+, CD11c+ (G), and B220+ (H) cells was determined in the lymph nodes and spleen at the basal level in the CD4 Cre or GPCR68 fl/fl CD4 Cre mice. (I-J) Flow cytometry was used to evaluate the CD4 + or CD8 + T cells for the determination of intracellular cytokines IFN-γ+ (I), or TNF-α+ (J) from the spleen and lymph nodes at basal level in the CD4 Cre or GPCR68 fl/fl CD4 Cre mice. Student t-test was performed for comparison between the two groups. Data are mean ± SEM (n = 5), ∗ p < 0.05.

Article Snippet: Naïve T cells were purified from lymph nodes as well as spleens of C57/BL6, CD4 Cre , GPCR68 fl/fl CD4 Cre (CKO) mice by using the mouse naïve CD4 + T Cell Isolation Kit (#130-104-453; Miltenyi Biotec) or naïve CD8 + T Cell Isolation Kit (#130-096-543; Miltenyi Biotec) for negative selection.

Techniques: Isolation, Quantitative RT-PCR, Expressing, Western Blot, Knock-Out, Generated, Flow Cytometry, Comparison

Journal: Bioactive Materials

Article Title: pH-neutralization strategy to suppress GPCR68 spatiotemporally activates T cells and enhances anti-tumor immunity

doi: 10.1016/j.bioactmat.2026.02.039

Figure Lengend Snippet: GPCR68 fl/fl CD4 Cre mice exhibit improved anti-tumor mmune responses. (A-C) Naïve CD4 + T cells were isolated from CD4 Cre or GPCR68 fl/fl CD4 Cre mice and activated using anti-CD3 and anti-CD28 using the culture media under physiologic neutral pH (7.4) or varying pH 6.0, 6.5, or 7.8. Flow cytometry plots showing the expression of IFN-γ and IL-2 in CD4 + T cells from CD4 Cre and GPCR68 fl/fl CD4 Cre mice. Each panel represents the frequency of IFN-γ + and IL-2 + cells. (B) Bar graph summarizing the percentage of IFN-γ + CD4 + T cells at each pH level for CD4 Cre and GPCR68 fl/fl CD4 Cre mice. (C) Bar graph showing the percentage of IL-2 + CD4 + T cells at each pH for CD4 Cre and GPCR68 fl/fl CD4 Cre mice. (D) Experimental timeline depicting tumor induction and treatment protocol in CD4 Cre and GPCR68 fl/fl CD4 Cre mice. (E) Tumor growth curves in CD4 Cre and GPCR68 fl/fl CD4 Cre mice. (F) Tumor weight in CD4 Cre versus GPCR68 fl/fl CD4 Cre mice at the time of harvesting on day 21. (G) Representative images of excised tumors at day 21. (H) Flow cytometric analysis of IFN-γ production by tumor-infiltrating CD4 + and CD8 + T cells. (I) Flow cytometric analysis of TNF-α production by tumor-infiltrating CD4 + and CD8 + T cells. Student t-test was performed for comparison between the two groups. Two-way ANOVA was used for multiple comparisons. Data are mean ± SEM (n = 5). ∗ p < 0.05, ∗∗ p < 0.01, ∗∗∗ p < 0.001, ns = not significant.

Article Snippet: Naïve T cells were purified from lymph nodes as well as spleens of C57/BL6, CD4 Cre , GPCR68 fl/fl CD4 Cre (CKO) mice by using the mouse naïve CD4 + T Cell Isolation Kit (#130-104-453; Miltenyi Biotec) or naïve CD8 + T Cell Isolation Kit (#130-096-543; Miltenyi Biotec) for negative selection.

Techniques: Isolation, Flow Cytometry, Expressing, Comparison

Journal: Bioactive Materials

Article Title: pH-neutralization strategy to suppress GPCR68 spatiotemporally activates T cells and enhances anti-tumor immunity

doi: 10.1016/j.bioactmat.2026.02.039

Figure Lengend Snippet: Anti-tumor effects of borate bioactive glass (BOLT) in B16 tumor. (A) Schematic illustration depicting the induction of B16 melanoma tumors, followed by treatment with BOLT at various time points, and tumor harvesting for subsequent analysis. (B) Tumor growth curves showing tumor volume in Control and BOLT-treated B16 melanoma tumors in mice. (C) Tumor weight at the time of harvesting in the BOLT-treated group compared to the Control. (D) Representative images of excised tumors from Control and BOLT-treated mice. (E) In vivo imaging of tumor-bearing mice in both the Control and BOLT-treated groups. (F) Flow cytometry analysis showing IFN-γ production in CD4 + and CD8 + T cells following BOLT treatment compared to Control. (G) Flow cytometry analysis demonstrated TNF-α production in CD4 + and CD8 + T cells in the BOLT-treated group, with a significant increase observed in CD8 + T cells. Student t-test was performed for comparison between the two groups. Two-way ANOVA was used for multiple comparisons. Data represent the mean ± SEM (n = 5). ∗ p < 0.05, ∗∗ p < 0.01.

Article Snippet: Naïve T cells were purified from lymph nodes as well as spleens of C57/BL6, CD4 Cre , GPCR68 fl/fl CD4 Cre (CKO) mice by using the mouse naïve CD4 + T Cell Isolation Kit (#130-104-453; Miltenyi Biotec) or naïve CD8 + T Cell Isolation Kit (#130-096-543; Miltenyi Biotec) for negative selection.

Techniques: Control, In Vivo Imaging, Flow Cytometry, Comparison

Journal: Bioactive Materials

Article Title: pH-neutralization strategy to suppress GPCR68 spatiotemporally activates T cells and enhances anti-tumor immunity

doi: 10.1016/j.bioactmat.2026.02.039

Figure Lengend Snippet: Combinational treatment of BOLT and anti-CTLA-4 blockade enhances anti-tumor immune response in B16 melanoma. (A) C57BL/6 mice were subcutaneously injected with 1 × 10 5 B16 melanoma cells on day 0 to induce tumors. On day 7, mice were randomly divided into groups and treated with either BOLT alone (intratumoral injection administered on alternate days starting from day 7), anti-CTLA-4 (intraperitoneal injection administered on days 9, 11, 13, and 15), or a combination of both treatments. PBS was used as a vehicle Control, while IgG was used as anti-CTLA-4 Control. Tumor growth was monitored throughout the treatment period, and tumors were harvested for analysis on day 21. (B-C) Tumor growth curves and area under the curve (AUC) analysis for WT mice treated with BOLT, with or without anti-CTLA-4 antibody, following subcutaneous injection of B16 melanoma cells. Tumor growth was monitored, and analysis was conducted on day 21. (D) Representative images of excised tumors at day 21, showed reduced tumor size in combination-treated mice. (E, F) Flow cytometry analysis of IFN-γ production by tumor-infiltrating CD4 + and CD8 + T cells. (G, H) Flow cytometry analysis of TNF-α production by tumor-infiltrating CD4 + and CD8 + T cells. Two-way ANOVA was used for multiple comparisons. Data are mean ± SEM (n = 5), ∗ p < 0.05, ∗∗ p < 0.01, ∗∗∗ p < 0.001, and ∗∗∗∗ p < 0.0001.

Article Snippet: Naïve T cells were purified from lymph nodes as well as spleens of C57/BL6, CD4 Cre , GPCR68 fl/fl CD4 Cre (CKO) mice by using the mouse naïve CD4 + T Cell Isolation Kit (#130-104-453; Miltenyi Biotec) or naïve CD8 + T Cell Isolation Kit (#130-096-543; Miltenyi Biotec) for negative selection.

Techniques: Injection, Control, Flow Cytometry