Primary Biliary Cholangitis in British Columbia First Nations: Clinical features and discovery of novel genetic susceptibility loci.

BACKGROUND & AIMS: Primary Biliary Cholangitis (PBC) is a chronic autoimmune liver disease characterized by destruction of intrahepatic bile ducts, portal inflammation and cirrhosis. Although rare in most populations, it is prevalent and often familial in British Columbia First Nations. We hypothesized that major genetic factors increased the risk in First Nations. METHODS: In all, 44 individuals with Primary Biliary Cholangitis and 61 unaffected relatives from 32 First Nations families participated. Family history and co-morbidities were documented. Medical records were reviewed and available biopsies were re-reviewed by our team pathologist. Genotyping was performed on DNA from 36 affected persons and 27 unaffected relatives using the Affymetrix Human Mapping 500K Array Set. MERLIN software was used to carry out multipoint parametric and nonparametric linkage analysis. Candidate genes were identified and entered into InnateDB and KEGG software to identify potential pathways affecting pathogenesis. RESULTS: In all, 34% of families were multiplex. Fifty per cent of cases and 33% of unaffected relatives reported other autoimmune disease. Three genomic regions (9q21, 17p13 and 19p13) produced LOD scores of 2.3 or greater suggestive of linkage, but no single linkage peak reached statistical significance. Candidate genes identified in the three regions suggested involvement of IL17, NFκB, IL6, JAK-STAT, IFNγ and TGFß immune signalling pathways. Specifically, four genes-ACT1, PIN1, DNMT1 and NTN1-emerged as having roles in these pathways that may influence Primary Biliary Cholangitis pathogenesis. CONCLUSIONS: Our whole genome linkage study results reflect the multifactorial nature of Primary Biliary Cholangitis, support previous studies suggesting signalling pathway involvement and identify new candidate genes for consideration.

The effects of glutamine supplementation on markers of apoptosis and autophagy in sickle cell disease peripheral blood mononuclear cells.

OBJECTIVES: L-Glutamine was FDA-approved for sickle cell disease (SCD) in 2017, yet the mechanism(s)-of-action are poorly understood. This study investigates the potential activation of autophagy as a previously unexplored mechanism-of-benefit. DESIGN: Prospective, open-label, 8-week, phase-2 trial of oral L-glutamine (10 g TID) in patients with SCD at risk for pulmonary hypertension identified by Doppler-echocardiography by an elevated tricuspid-regurgitant-jet-velocity (TRV)≥ 2.5 m/s. Peripheral blood mononuclear cells (PBMCs) were isolated from blood samples taken from SCD patients at baseline, two, four, six and eight weeks of glutamine therapy, and from controls at baseline; BAX (pro-apoptotic marker) and LC3-II/LC3-I (autophagy marker) were measured via western blot analysis to assess apoptosis and autophagy respectively. SETTING: Comprehensive SCD Center in Oakland, California. RESULTS: Patients with SCD (n = 8) had a mean age of 44 ± 16, 50% were male; 63% Hb-SS, and mean TRV= 3.1 ± 0.7 m/s. Controls' mean age (n = 5) was 32 ± 12% and 57% were male; all were Hb-AA with a mean TRV= 1.8 ± 0.6. At baseline, SCD-PBMCs had 2-times higher levels of BAX and LC3-I versus controls (both p = 0.03). Levels of BAX expression increased by 300% after 8-weeks of glutamine supplementation (p = 0.005); LC3-I protein levels decreased while LC3-II levels increased by 70%, giving a significant increase in the LC3-II/LC3-I ratio (p = 0.02). CONCLUSION: PBMCs from glutamine-supplemented SCD patients have upregulated apoptotic and autophagy proteins. The parallel increase in BAX and the LC3-II / LC3-I ratio with glutamine supplementation suggest a possible role of autophagic cell death. The increase in apoptotic markers provide insight into a possible mechanism used by peripheral PBMCs during glutamine supplementation in patients with SCD.