Fig 2: Antigen presentation in response to Pseudomonas aeruginosa (P. aeruginosa) is modulated by glucocerebrosidase (GCase) activity. Bar graphs overlaid with scatter plots showing expression of major histocompatibility complex class II (MHC‐II) human leukocyte antigen (HLA)‐DR in peripheral blood mononuclear cells from neurologically healthy controls (NHCs), idiopathic Parkinson's disease (iPD) patients, LRRK2‐PD patients, and GBA‐PD patients after P. aeruginosa treatment. (A) HLA‐DR expression in T cells (effect of interaction P = 0.9805, treatment P = 0.1262, cohort P = 0.0031). (B) HLA‐DR expression in classical monocytes (effect of interaction P = 0.9010, treatment P = 0.9867, cohort P = 0.0001). (C) HLA‐DR expression in intermediate monocytes (effect of interaction P = 0.9218, treatment P = 0.0961, cohort P = 0.0498). (D) HLA‐DR expression in nonclassical monocytes (effect of interaction P = 0.2178, treatment P = 0.0152, cohort P = 0.0047). (E) HLA‐DR expression in CD3−/CD14−/CD16− cells (effect of interaction P = 0.5764, treatment P = 0.0579, cohort P = 0.0010). Bars represent mean ± standard error of the mean. NHCs, n = 24; iPD, n = 33; LRRK2‐PD, n = 21; GBA‐PD, n = 17. Each symbol represents the measurement from a single individual. The results in A–E were analyzed using two‐way analysis of variance with Tukey's corrections for multiple comparisons. Only comparisons within treatment and comparisons within cohorts across treatment are shown. Statistically significant differences defined by P < 0.05 are shown. [Color figure can be viewed at wileyonlinelibrary.com]

Fig 3: Proposed model for NCGC00188758 (NCG) effects at the lysosome in GBA1 and LRRK2 mutant immune cells. GBA1 mutant cells express decreased levels of glucocerebrosidase (GCase) at baseline. In response to immune stimulation, compensatory mechanisms that enhance/support GCase function are upregulated, contributing to a ceiling effect where NCG has limited ability to further increase GCase activity. In LRRK2 mutant cells, lysosomal defects are more widespread and compensatory mechanisms may be less effective. This leads to lysosomal buildup of glucosylceramide (GlcCer), impaired acidification, and an accumulation of dysfunctional lysosomes. NCG improves GCase trafficking in these cells, partially rescuing lysosomal defects, and contributes to increased major histocompatibility complex class II (MHC‐II) processing and surface expression. [Color figure can be viewed at wileyonlinelibrary.com]

Fig 4: Effects of LRRK2 kinase inhibition and glucocerebrosidase (GCase) activation on stimulation‐dependent expression of LRRK2. Bar graphs overlaid with scatter plots showing expression of LRRK2 in peripheral blood mononuclear cells (PBMCs) from neurologically healthy controls (NHCs), idiopathic Parkinson's disease (iPD) patients, LRRK2‐PD patients, and GBA‐PD patients after Pseudomonas aeruginosa (P. aeruginosa) treatment. (A) LRRK2 mean fluorescence intensity (MFI) in CD3+ T cells (effect of interaction P = 0.3118, treatment P < 0.0001, cohort P = 0.0004). (B) LRRK2 MFI in classical monocytes (effect of interaction P = 0.5111, treatment P = 0.0004, cohort P = 0.0029). (C) LRRK2 MFI in intermediate monocytes (effect of interaction P = 0.8221, treatment P < 0.0001, cohort P = 0.0983). (D) LRRK2 MFI in nonclassical monocytes (effect of interaction P = 0.6949, treatment P = 0.0091, cohort P = 0.0001). (E) LRRK2 MFI in CD3−/CD14−/CD16− cells (effect of interaction P = 0.6618, treatment P = 0.0699, cohort p = 0.0012). Bars represent mean ± standard error of the mean. NHCs, n = 24; iPD, n = 33; LRRK2‐PD, n = 21; GBA‐PD, n = 17. Each symbol represents the measurement from a single individual. The results in A–E were analyzed using two‐way analysis of variance with Tukey's corrections for multiple comparisons. Only comparisons within treatment and comparisons within cohorts across treatment are shown. Statistically significant differences defined by P < 0.05 are shown. [Color figure can be viewed at wileyonlinelibrary.com]

Fig 5: GBA‐Parkinson's disease (PD) peripheral immune cells exhibit greater stimulation‐evoked secretion of proinflammatory cytokines. Bar graphs overlaid with scatter plots showing secretion of inflammatory cytokines after Pseudomonas aeruginosa treatment from peripheral blood mononuclear cells from neurologically healthy controls (NHCs), idiopathic PD (iPD) patients, LRRK2‐PD patients, and GBA‐PD patients. (A) Secretion of interleukin (IL)‐1β (effect of interaction P > 0.9999, treatment P = 0.9246, cohort P < 0.0001). (B) IL‐2 (effect of interaction P = 0.3396, treatment P = 0.3138, cohort P < 0.0001). (C) Secretion of tumor necrosis factor (effect of interaction P = 0.8677, treatment P = 0.6192, cohort P < 0.0001). (D) Secretion of IL‐8 (effect of interaction P > 0.9999, treatment P = 0.9295, cohort P = 0.1874). (E) Secretion of IL‐10 (effect of interaction P = 0.9997, treatment P = 0.9156, cohort P = 0.0570). Bars represent mean ± standard error of the mean. NHCs, n = 24; iPD, n = 33; LRRK2‐PD, n = 21; GBA‐PD, n = 17. Each symbol represents the measurement from a single individual. The results in A–E were analyzed using two‐way analysis of variance with Tukey's corrections for multiple comparisons. Only comparisons within treatment and comparisons within cohorts across treatment are shown. Statistically significant differences defined by P < 0.05 are shown. [Color figure can be viewed at wileyonlinelibrary.com]