Serum programmed cell death proteins in amyotrophic lateral sclerosis

CD4 T-cell aging exacerbates neuroinflammation in a late-onset mouse model of amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is an adult-onset progressive neurodegenerative disorder characterized by the loss of upper and lower motor neurons in the brain and spinal cord. Accumulating evidence suggests that ALS is not solely a neuronal cell- or brain tissue-autonomous disease and that neuroinflammation plays a key role in disease progression. Furthermore, whereas both CD4 and CD8 T cells were observed in spinal cords of ALS patients and in mouse models of the disease, their role in the neuroinflammatory process, especially considering their functional changes with age, is not fully explored. In this study, we revealed the structure of the CD4 T-cell compartment during disease progression of early-onset SOD1G93A and late-onset SOD1G37R mouse models of ALS. We show age-related changes in the CD4 T-cell subset organization between these mutant SOD1 mouse models towards increased frequency of effector T cells in spleens of SOD1G37R mice and robust infiltration of CD4 T cells expressing activation markers and the checkpoint molecule PD1 into the spinal cord. The frequency of infiltrating CD4 T cells correlated with the frequency of infiltrating CD8 T cells which displayed a more exhausted phenotype. Moreover, RNA-Seq and immunohistochemistry analyses of spinal cords from SOD1G37R mice with early clinical symptoms demonstrated immunological trajectories reminiscent of a neurotoxic inflammatory response which involved proinflammatory T cells and antigen presentation related pathways. Overall, our findings suggest that age-related changes of the CD4 T cell landscape is indicative of a chronic inflammatory response, which aggravates the disease process and can be therapeutically targeted.

Therapy of autoimmune inflammation in sporadic amyotrophic lateral sclerosis: Dimethyl fumarate and H-151 downregulate inflammatory cytokines in the cGAS-STING pathway

In sporadic amyotrophic lateral sclerosis (sALS), IL-17A- and granzyme-positive cytotoxic T lymphocytes (CTL), IL-17A-positive mast cells, and inflammatory macrophages invade the brain and spinal cord. In some patients, the disease starts following a trauma or a severe infection. We examined cytokines and cytokine regulators over the disease course and found that, since the early stages, peripheral blood mononuclear cells (PBMC) exhibit increased expression of inflammatory cytokines IL-12A, IFN-γ, and TNF-α, as well as granzymes and the transcription factors STAT3 and STAT4. In later stages, PBMCs upregulated the autoimmunity-associated cytokines IL-23A and IL-17B, and the chemokines CXCL9 and CXCL10, which attract CTL and monocytes into the central nervous system. The inflammation is fueled by the downregulation of IL-10, TGFβ, and the inhibitory T-cell co-receptors CTLA4, LAG3, and PD-1, and, in vitro, by stimulation with the ligand PD-L1. We investigated in two sALS patients the regulation of the macrophage transcriptome by dimethyl fumarate (DMF), a drug approved against multiple sclerosis and psoriasis, and the cyclic GMP-AMP synthase/stimulator of interferon genes (cGAS/STING) pathway inhibitor H-151. Both DMF and H-151 downregulated the expression of granzymes and the pro-inflammatory cytokines IL-1β, IL-6, IL-15, IL-23A, and IFN-γ, and induced a pro-resolution macrophage phenotype. The eicosanoid epoxyeicosatrienoic acids (EET) from arachidonic acid was anti-inflammatory in synergy with DMF. H-151 and DMF are thus candidate drugs targeting the inflammation and autoimmunity in sALS via modulation of the NFκB and cGAS/STING pathways.

Personalized Precision Immunotherapy for Amyotrophic Lateral Sclerosis (ALS)

Neurological syndrome amyotrophic lateral sclerosis (ALS) affects motor neurons and is characterized by progressive motor neuron loss in the brain and spinal cord. ALS starts with mainly focal onset but when the disease progresses, it spreads to different parts of the body, with survival limits of 2-5 years after disease initiation. To date, only supportive care is provided for ALS patients, and no effective treatment or cure has been discovered. This review is focused on clinical and immunological aspects of ALS patients, based on our case studies, and we discuss the treatment we have provided to those patients based on a detailed evaluation of their peripheral blood immune cells and blood-derived serum secreted factors, cytokines, chemokines and growth factors. We show that using a personalized approach of low dose immunotherapy there is an improvement in the effects on inflammation and immunological dysfunction.

Tregs Attenuate Peripheral Oxidative Stress and Acute Phase Proteins in ALS

Oxidative stress (OS) induces inflammation, which in turn exacerbates OS and the expression of acute phase proteins (APPs). Regulatory T lymphocyte (Treg) therapy was assessed for suppression of OS and APP responses in longitudinal serum samples from subjects with amyotrophic lateral sclerosis (ALS) enrolled in a phase I clinical trial. The first round of Treg therapy suppressed levels of oxidized low‐density lipoprotein (ox‐LDL). During a 6‐month washout period, ox‐LDL levels increased. A second round of therapy again suppressed ox‐LDL levels and then rose following the cessation of treatment. Serum levels of APPs, soluble CD14, lipopolysaccharide binding protein, and C‐reactive protein, were stabilized during Treg administrations, but rose during the washout period and again after therapy was discontinued. Treg therapy potentially suppresses peripheral OS and the accompanying circulating pro‐inflammatory induced APPs, both of which may serve as peripheral candidates for monitoring efficacies of immunomodulating therapies. ANN NEUROL 2022;92:195–200

Amyotrophic lateral sclerosis is a systemic disease: peripheral contributions to inflammation-mediated neurodegeneration

PURPOSE OF REVIEW

Neuroinflammation is an important mediator of the pathogenesis of disease in amyotrophic lateral sclerosis (ALS). Genetic mutations such as C9orf72 have begun to define the numerous cell autonomous pathways that initiate motor neuron injury. Yet, it is the signalling to surrounding glia and peripherally derived immune cells that initiates the noncell autonomous inflammatory process and promotes self-propagating motor neuron cell death. The purpose of this review is to explore the systemic immune/inflammatory contributions to the pathogenesis of ALS: what are the peripheral pro-inflammatory signatures, what initiates their presence and do they represent potential therapeutic targets.

RECENT FINDINGS

In ALS, motor neuron cell death is initiated by multiple cell autonomous pathways leading to misfolded proteins, oxidative stress, altered mitochondria, impaired autophagy and altered RNA metabolism, which collectively promote noncell autonomous inflammatory reactivity. The resulting disease is characterized by activated microglia and astrocytes as well as peripherally derived pro-inflammatory innate and adaptive immune cells. In this unrelenting disorder, circulating blood monocytes and natural killer cells are pro-inflammatory. Furthermore, regulatory T lymphocytes are dysfunctional, and pro-inflammatory cytokines and acute phase proteins are elevated.

SUMMARY

The collective dysregulation of cells and cytokines in patients with ALS accurately reflect increased disease burdens, more rapid progression rates and reduced survival times, reinforcing the concept of ALS as a disorder with extensive systemic pro-inflammatory responses. These increased systemic pro-inflammatory immune constituents provide potentially meaningful therapeutic targets.