Allogeneic B cell immunomodulatory therapy in amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is an orphan neurodegenerative disease. Immune system dysregulation plays an essential role in ALS onset and progression. Our preclinical studies have shown that the administration of exogenous allogeneic B cells improves outcomes in murine models of skin and brain injury through a process termed pligodraxis, in which B cells adopt an immunoregulatory and neuroprotective phenotype in an injured environment. Here, we investigated the effects of B-cell therapy in the SOD1G93A mouse preclinical model of ALS and in a person living with ALS. Purified splenic mature naïve B cells from haploidentical donor mice were administered intravenously in SOD1G93A mice for a total of 10 weekly doses. For the clinical study in a person with advanced ALS, IgA gammopathy of unclear significance, and B lymphopenia, CD19+ B cells were positively selected from a healthy haploidentical donor and infused intravenously twice, at a 60-day interval. Repeated intravenous B-cell administration was safe and significantly delayed disease onset, extended survival, reduced cellular apoptosis, and decreased astrogliosis in SOD1G93A mice. Repeated B-cell infusion in a person with ALS was safe and did not appear to generate a clinically evident inflammatory response. An improvement of 5 points on the ALSFRS-R scale was observed after the first infusion. Levels of inflammatory markers showed persistent reduction post-infusion. This represents a first demonstration of the efficacy of haploidentical B-cell infusion in the SOD1G93A mouse and the safety and feasibility of using purified haploidentical B lymphocytes as a cell-based therapeutic strategy for a person with ALS.

B cells support the repair of injured tissues by adopting MyD88-dependent regulatory functions and phenotype.

Exogenously applied mature naïve B220+ /CD19+ /IgM+ /IgD+ B cells are strongly protective in the context of tissue injury. However, the mechanisms by which B cells detect tissue injury and aid repair remain elusive. Here, we show in distinct models of skin and brain injury that MyD88-dependent toll-like receptor (TLR) signaling through TLR2/6 and TLR4 is essential for the protective benefit of B cells in vivo, while B cell-specific deletion of MyD88 abrogated this effect. The B cell response to injury was multi-modal with simultaneous production of both regulatory cytokines, such as IL-10, IL-35, and transforming growth factor beta (TGFß), and inflammatory cytokines, such as tumor necrosis factor alpha (TNFα), IL-6, and interferon gamma. Cytometry analysis showed that this response was time and environment-dependent in vivo, with 20%-30% of applied B cells adopting an immune modulatory phenotype with high co-expression of anti- and pro-inflammatory cytokines after 18-48 h at the injury site. B cell treatment reduced the expression of TNFα and increased IL-10 and TGFß in infiltrating immune cells and fibroblasts at the injury site. Proteomic analysis further showed that B cells have a complex time-dependent homeostatic effect on the injured microenvironment, reducing the expression of inflammation-associated proteins, and increasing proteins associated with proliferation, tissue remodeling, and protection from oxidative stress. These findings chart and validate a first mechanistic understanding of the effects of B cells as an immunomodulatory cell therapy in the context of tissue injury.

Harnessing CXCL12 signaling to protect and preserve functional ß-cell mass and for cell replacement in type 1 diabetes.

Type 1 diabetes (T1D) is a complex multifactorial disease characterized by autoimmune destruction of insulin-producing pancreatic ß cells. Our understanding of the pathogenic mechanisms and natural history of T1D has evolved significantly over the past two decades; we can efficiently predict high-risk individuals, early diagnose the disease and stage progression. Fortuitously, novel in vitro differentiation protocols for generating functional ß-like cells from human pluripotent stem cells have been developed. These advances provide a definitive roadmap to implement realistic preventive and ß-cell replacement therapies in T1D. Immunoprotection and preservation of functional ß-cell mass are a sine qua non for the success of these interventions. The chemokine, stromal cell-derived factor-1alpha, known as CXCL12-α, is an attractive therapeutic target molecule in this context. CXCL12-α signaling promotes ß-cell development, survival and regeneration and can mediate local immunomodulation in the pancreatic islets. Interestingly, CXCL12-α is robustly expressed in maturing insulin-producing ß cells and in adult ß cells during periods of injury and regeneration. However, under normal physiological settings, CXCL12-α is repressed in terminally differentiated mature ß cells and islets. Here, we provide a comprehensive overview of the role of CXCL12-α signaling in ß-cell biology, physiology and immune regulation. We discuss CXCL12-α signaling mechanisms that could be harnessed to modulate ß-cell autoimmunity, protect and preserve functional ß-cell mass and for cell replacement therapy in T1D.