Tofacitinib Suppresses Natural Killer Cells In Vitro and In Vivo: Implications for Amyotrophic Lateral Sclerosis

Abstract

Amyotrophic lateral sclerosis (ALS) is a fatal and incurable neurodegenerative disease with few therapeutic options. However, the immune system, including natural killer (NK) cells, is linked to ALS progression and may constitute a viable therapeutic ALS target. Tofacitinib is an FDA-approved immunomodulating small molecule which suppresses immune cell function by blocking proinflammatory cytokine signaling. This includes the cytokine IL-15 which is the primary cytokine associated with NK cell function and proliferation. However, the impact of tofacitinib on NK activation and cytotoxicity has not been thoroughly investigated, particularly in ALS. We therefore tested the ability of tofacitinib to suppress cytotoxicity and cytokine production in an NK cell line and in primary NK cells derived from control and ALS participants. We also investigated whether tofacitinib protected ALS neurons from NK cell cytotoxicity. Finally, we conducted a comprehensive pharmacokinetic study of tofacitinib in mice and tested the feasibility of administration formulated in chow. Success was assessed through the impact of tofacitinib on peripheral NK cell levels in mice. We found tofacitinib suppressed IL-15-induced activation as measured by STAT1 phosphorylation, cytotoxicity, pro-inflammatory gene expression, and pro-inflammatory cytokine secretion in both an NK cell line and primary NK cells. Furthermore, tofacitinib protected ALS neurons from NK cell-mediated cytotoxicity. In mice, we found tofacitinib bioavailability was 37% in both male and female mice; using these data we formulated mouse containing low and high doses of tofacitinib and found that the drug suppressed peripheral NK cell levels in a dose-dependent manner. These results demonstrate that tofacitinib can suppress NK cell function and may be a viable therapeutic strategy for ALS.

Neutrophils Are Associated with Higher Risk of Incident Amyotrophic Lateral Sclerosis in a BMI‐ and Age‐Dependent Manner

“…The peripheral immune system includes the innate immune system, with neutrophils as its core component, and the adaptive immune system, with lymphocytes as its core component. Different immune cell subpopulations display different functions in ALS disease progression; T regulatory cells (Tregs) appear to be protective, 3 whereas neutrophils, inflammatory monocytes, and CD8 + T cells may be destructive 4–6 . The modulation of peripheral immune cells, which is feasible and less invasive, has been shown to delay the progression of ALS, making peripheral immune cells attractive intervention targets in the ALS field 7–9 .…”

“…Different immune cell subpopulations display different functions in ALS disease progression; T regulatory cells (Tregs) appear to be protective, 3 whereas neutrophils, inflammatory monocytes, and CD8 + T cells may be destructive. [4][5][6] The modulation of peripheral immune cells, which is feasible and less invasive, has been shown to delay the progression of ALS, making peripheral immune cells attractive intervention targets in the ALS field. [7][8][9] Therefore, the search for precise immune therapies targeting specific subsets of peripheral immune cells will improve the immune-mediated pathological deterioration of ALS and will be of great value in the treatment of ALS.…”

Identification of an immune-related gene prognostic index for predicting prognosis, immunotherapeutic efficacy, and candidate drugs in amyotrophic lateral sclerosis

“…Macrophages M0, monocytes and resting NK cells were more abundant in the IRGPI-high subtype, while memory B cells and resting mast cells were more abundant in the IRGPI-low subtype. Peripheral monocytes and NK cells were involved in ALS pathophysiology ( Murdock et al, 2016 ; Jin et al, 2020 ; McCombe et al, 2020 ; Gaur et al, 2021 ; Figueroa-Romero et al, 2022 ). NF-κB induces the release of associated inflammatory mediators ( Liu T. et al, 2017 ).…”

Impact of the National Amyotrophic Lateral Sclerosis Registry: Analysis of Registry‐funded Research

“…Feldman, Eva 2018 $1,530,000 Goutman, 2020 26 De Marchi, 2021 27 Murdock, 2021 28 Figueroa-Romero, 2022 29 Goutman, 2022 30 frequently, environmental and occupational risk factors were principally explored (6 studies), typically related to toxic metal exposure (e.g., lead, mercury) and agricultural chemicals (e.g., pesticides, herbicides), as well as occupations associated with exposure to these substances, which are also included in ATSDR's List of Priority Substances. 11 Genetic, metabolic, or immunologic risk factors were the primary focus of four studies, while medical treatment approaches were the primary focus of the remaining three studies.…”

“…Subgroup analysis: insufficient representation of specific ALS subgroups in preclinical studies) 18,21,25,26,29 • Targeted case sampling (e.g., high-exposure patients for selected environmental factors, specific genetic signatures, sex, age) 18,29 Reverse causality: insufficient detail on exposure timing and duration in reported information. 26,28 • Prospective cohort studies (e.g., revealing temporal relationships) 21,26 • Mechanistic studies (identification of prediagnostic exposure pathways, prediction of ALS course) 26 too recently for the scientific community to cite.…”