biostudies-literatureReed ECNHLBI NIH HHSNIGMS NIH HHS1725904https://www.ebi.ac.uk/biostudies/studies/S-EPMC12823933biostudies-literatureUnknown16We have recently discovered hemoglobin alpha a1 (Hbα-a1 mRNA and Hbα protein) in T-lymphocytes and previously reported that its expression was sensitive to mitochondrial redox perturbations. However, outside of its occurrence and basic characterization, the functional role of Hbα in T-lymphocytes remained unknown. Herein, we identify Hbα in both CD4⁺ and CD8⁺ T-lymphocyte subsets, and found its expression is highly dynamic, differs between the two subtypes, and is dependent upon activation stage. Further, the loss of Hbα by use of a novel T-lymphocyte-specific Hbα knock-out mouse impairs mitochondrial function, dysregulates cytokine production, and lowers the activation threshold primarily in CD4⁺ T-lymphocytes, indicating a critical role for Hbα within this subset. While these data suggested the loss of Hbα in T-lymphocytes may promote aberrant activation of autoreactive T-lymphocytes, surprisingly, we discovered that mice lacking Hbα in T-lymphocytes exhibited reduced severity of experimental autoimmune encephalomyelitis (EAE) compared to wild-type control animals. Interestingly, T-lymphocytes lacking Hbα <i>in vivo</i> appeared to function identically to wild-type controls, which did not explain the protection against EAE. In contrast, T-lymphocyte Hbα knock-out mice displayed significantly reduced levels of circulating immunoglobulins and CD40L expression compared to their wild-type counterparts during EAE, suggesting possible impaired intercellular communication. These data elucidate a previously unrecognized role for Hbα in T-lymphocyte function, which may have implications for hemoglobin-related diseases (i.e., hemoglobinopathies).Frontiers in immunologyHemoglobin alpha regulates T-lymphocyte activation and mitochondrial function.PMC12823933R01 HL158521F31 HL176172T32 GM135115Griffin BLPitts LJNatour TCase AJPasupuleti SLauten THReed ECJojo CNfalseHemoglobin alpha regulates T-lymphocyte activation and mitochondrial function.We have recently discovered hemoglobin alpha a1 (Hbα-a1 mRNA and Hbα protein) in T-lymphocytes and previously reported that its expression was sensitive to mitochondrial redox perturbations. However, outside of its occurrence and basic characterization, the functional role of Hbα in T-lymphocytes remained unknown. Herein, we identify Hbα in both CD4⁺ and CD8⁺ T-lymphocyte subsets, and found its expression is highly dynamic, differs between the two subtypes, and is dependent upon activation stage. Further, the loss of Hbα by use of a novel T-lymphocyte-specific Hbα knock-out mouse impairs mitochondrial function, dysregulates cytokine production, and lowers the activation threshold primarily in CD4⁺ T-lymphocytes, indicating a critical role for Hbα within this subset. While these data suggested the loss of Hbα in T-lymphocytes may promote aberrant activation of autoreactive T-lymphocytes, surprisingly, we discovered that mice lacking Hbα in T-lymphocytes exhibited reduced severity of experimental autoimmune encephalomyelitis (EAE) compared to wild-type control animals. Interestingly, T-lymphocytes lacking Hbα <i>in vivo</i> appeared to function identically to wild-type controls, which did not explain the protection against EAE. In contrast, T-lymphocyte Hbα knock-out mice displayed significantly reduced levels of circulating immunoglobulins and CD40L expression compared to their wild-type counterparts during EAE, suggesting possible impaired intercellular communication. These data elucidate a previously unrecognized role for Hbα in T-lymphocyte function, which may have implications for hemoglobin-related diseases (i.e., hemoglobinopathies).2025-01-01T00:00:00Z20252026-06-19T03:12:14.082Z2026-06-19T03:07:24.829ZS-EPMC128239334158345810.3389/fimmu.2025.1725904