title: Impaired calcium mobilization in natural killer cells from chronic fatigue syndrome/myalgic encephalomyelitis patients is associated with transient receptor potential melastatin 3 ion channels.
abstract: Transient receptor potential melastatin subfamily 3 (TRPM3) ion channels play a role in calcium (Ca2+) cell signalling. Reduced TRPM3 protein expression has been identified in chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) patients. However, the significance of TRPM3 and association with intracellular Ca2+mobilization has yet to be determined. Fifteen CFS/ME patients (mean age 48·82 ± 9·83 years) and 25 healthy controls (mean age 39·2 ± 12·12 years) were examined. Isolated natural killer (NK) cells were labelled with fluorescent antibodies to determine TRPM3, CD107a and CD69 receptors on CD56dimCD16+NK cells and CD56brightCD16dim/-NK cells. Ca2+flux and NK cytotoxicity activity was measured under various stimulants, including pregnenolone sulphate (PregS), thapsigargin (TG), 2-aminoethoxydiphenyl borate (2APB) and ionomycin. Unstimulated CD56brightCD16dim/-NK cells showed significantly reduced TRPM3 receptors in CFS/ME compared with healthy controls (HC). Ca2+flux showed no significant difference between groups. Moreover, PregS-stimulated CD56brightCD16dim/-NK cells showed a significant increase in Ca2+flux in CFS/ME patients compared with HC. By comparison, unstimulated CD56dimCD16+NK cells showed no significant difference in both Ca2+flux and TRPM3 expression. PregS-stimulated CD56dimCD16+NK cells increased TRPM3 expression significantly in CFS/ME, but this was not associated with a significant increase in Ca2+flux. Furthermore, TG-stimulated CD56dimCD16+NK cells increased K562 cell lysis prior to PregS stimulation in CFS/ME patients compared with HC. Differential expression of TRPM3 and Ca2+flux between NK cell subtypes may provide evidence for their role in the pathomechanism involving NK cell cytotoxicity activity in CFS/ME.
authors.affiliation: The National Centre for Neuroimmunology and Emerging Diseases, Menzies Health Institute, Gold Coast, QLD, Australia.|School of Medical Science, Griffith University, Gold Coast, QLD, Australia.
authors.forename: T
authors.initials: T
authors.lastname: Nguyen
authors.affiliation: The National Centre for Neuroimmunology and Emerging Diseases, Menzies Health Institute, Gold Coast, QLD, Australia.|School of Medical Science, Griffith University, Gold Coast, QLD, Australia.
authors.forename: S
authors.initials: S
authors.lastname: Johnston
authors.affiliation: The National Centre for Neuroimmunology and Emerging Diseases, Menzies Health Institute, Gold Coast, QLD, Australia.|School of Medical Science, Griffith University, Gold Coast, QLD, Australia.
authors.forename: L
authors.initials: L
authors.lastname: Clarke
authors.affiliation: The National Centre for Neuroimmunology and Emerging Diseases, Menzies Health Institute, Gold Coast, QLD, Australia.
authors.forename: P
authors.initials: P
authors.lastname: Smith
authors.affiliation: The National Centre for Neuroimmunology and Emerging Diseases, Menzies Health Institute, Gold Coast, QLD, Australia.|School of Medical Science, Griffith University, Gold Coast, QLD, Australia.
authors.forename: D
authors.initials: D
authors.lastname: Staines
authors.affiliation: The National Centre for Neuroimmunology and Emerging Diseases, Menzies Health Institute, Gold Coast, QLD, Australia.|School of Medical Science, Griffith University, Gold Coast, QLD, Australia.
authors.forename: S
authors.initials: S
authors.lastname: Marshall-Gradisnik
mesh_terms: D000328:Adult; D019002:CD56 Antigen / Q000378:metabolism; D020013:Calcium Signaling; D003602:Cytotoxicity, Immunologic; D015673:Fatigue Syndrome, Chronic / Q000235:genetics*; D005260:Female; D006801:Humans; D020014:K562 Cells; D007694:Killer Cells, Natural / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D011284:Pregnenolone / Q000378:metabolism; D017452:Receptors, IgG / Q000378:metabolism; D050053:TRPM Cation Channels / Q000235:genetics*; D019284:Thapsigargin / Q000378:metabolism
chemical_list: D019002:CD56 Antigen; D017452:Receptors, IgG; D050053:TRPM Cation Channels; C475667:TRPM3 protein, human; C018370:pregnenolone sulfate; D019284:Thapsigargin; D011284:Pregnenolone
keywords: cell surface molecules; inhibitory/activating receptors; natural killer cells