Nitrated α–Synuclein Immunity Accelerates Degeneration of Nigral Dopaminergic Neurons

The neuropathology of Parkinson's disease (PD) includes loss of dopaminergic neurons in the substantia nigra, nitrated alpha-synuclein (N-alpha-Syn) enriched intraneuronal inclusions or Lewy bodies and neuroinflammation. While the contribution of innate microglial inflammatory activities to disease are known, evidence for how adaptive immune mechanisms may affect the course of PD remains obscure. We reasoned that PD-associated oxidative protein modifications create novel antigenic epitopes capable of peripheral adaptive T cell responses that could affect nigrostriatal degeneration.Nitrotyrosine (NT)-modified alpha-Syn was detected readily in cervical lymph nodes (CLN) from 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) intoxicated mice. Antigen-presenting cells within the CLN showed increased surface expression of major histocompatibility complex class II, initiating the molecular machinery necessary for efficient antigen presentation. MPTP-treated mice produced antibodies to native and nitrated alpha-Syn. Mice immunized with the NT-modified C-terminal tail fragment of alpha-Syn, but not native protein, generated robust T cell proliferative and pro-inflammatory secretory responses specific only for the modified antigen. T cells generated against the nitrated epitope do not respond to the unmodified protein. Mice deficient in T and B lymphocytes were resistant to MPTP-induced neurodegeneration. Transfer of T cells from mice immunized with N-alpha-Syn led to a robust neuroinflammatory response with accelerated dopaminergic cell loss.These data show that NT modifications within alpha-Syn, can bypass or break immunological tolerance and activate peripheral leukocytes in draining lymphoid tissue. A novel mechanism for disease is made in that NT modifications in alpha-Syn induce adaptive immune responses that exacerbate PD pathobiology. These results have implications for both the pathogenesis and treatment of this disabling neurodegenerative disease

CD4+ Regulatory and Effector/Memory T Cell Subsets Profile Motor Dysfunction in Parkinson’s Disease

Animal models and clinical studies have linked the innate and adaptive immune system to the pathology of Parkinson’s disease (PD). Despite such progress, the specific immune responses that influence disease progression have eluded investigators. Herein, we assessed relationships between T cell phenotype and function with PD progression. Peripheral blood lymphocytes from two separate cohorts, a discovery cohort and a validation cohort, totaling 113 PD patients and 96 age- and environment-matched caregivers were examined by flow cytometric analysis and T cell proliferation assays. Increased effector/memory T cells (Tem), defined as CD45RO+ and FAS+ CD4+ T cells and decreased CD31+ and α4β7+ CD4+ T cells were associated with progressive Unified Parkinson’s Disease Rating Scale III scores. However, no associations were seen between immune biomarkers and increased age or disease duration. Impaired abilities of regulatory T cells (Treg) from PD patients to suppress effector T cell function was observed. These data support the concept that chronic immune stimulation, notably Tem activation and Treg dysfunction is linked to PD pathobiology and disease severity, but not disease duration. The association of T cell phenotypes with motor symptoms provides fresh avenues for novel biomarkers and therapeutic designs

Regulating STING in health and disease.

The presence of cytosolic double-stranded DNA molecules can trigger multiple innate immune signalling pathways which converge on the activation of an ER-resident innate immune adaptor named "STimulator of INterferon Genes (STING)". STING has been found to mediate type I interferon response downstream of cyclic dinucleotides and a number of DNA and RNA inducing signalling pathway. In addition to its physiological function, a rapidly increasing body of literature highlights the role for STING in human disease where variants of the STING proteins, as well as dysregulated STING signalling, have been implicated in a number of inflammatory diseases. This review will summarise the recent structural and functional findings of STING, and discuss how STING research has promoted the development of novel therapeutic approaches and experimental tools to improve treatment of tumour and autoimmune diseases

Common genetic variation in the <em>HLA</em> region is associated with late-onset sporadic Parkinson's disease

Parkinson’s diseas