Anti-KRT18 monoclonal antibody, clone N31

BACKGROUND & AIMS: Keratins 8 and 18 (K8/K18) provide anti-apoptotic functions upon liver injury. The cytoprotective function of keratins explains the overrepresentation of K8/K18 variants in patients with cirrhosis. However, K8/K18 variant-associated susceptibility to acute liver injury, which is well-described in animal models, has not been studied in humans. METHODS: We analyzed the entire coding regions of KRT8 and KRT18 genes (15 total exons and their exon-intron boundaries) to determine the frequency of K8/K18 variants in 344 acute liver failure (ALF) patients (49% acetaminophen-related) and 2 control groups (African-American [n = 245] and previously analyzed white [n = 727] subjects). RESULTS: Forty-five ALF patients had significant amino-acid-altering K8/K18 variants, including 23 with K8 R341H and 11 with K8 G434S. K8 variants were significantly more common (total of 42 patients) than K18 variants (3 patients) (P < .001). We found increased frequency of variants in white ALF patients (9.1%) versus controls (3.7%) (P = .01). K8 R341H was more common in white (P = .01) and G434S was more common in African-American (P = .02) ALF patients versus controls. White patients with K8/K18 variants were less likely to survive ALF without transplantation (P = .02). K8 A333A and G434S variants associated exclusively with African Americans (23% combined frequency in African American but none in white controls; P < .0001), while overall, K18 variants were more common in non-white liver-disease subjects compared to whites (2.8% vs 0.6%, respectively; P = .008). CONCLUSIONS: KRT8 and KRT18 are important susceptibility genes for ALF development. Presence of K8/K18 variants predisposes to adverse ALF outcome, and some variants segregate with unique ethnic and race backgrounds.

Urine-derived stem cells (USCs) have shown potentials for the treatment of skeletal and urological disorders. Based on published literature and our own data, USCs consist of heterogeneous populations of cells. In this paper, we identify and characterize two morphologically distinct subpopulations of USCs from human urine samples, named as spindle-shaped USCs (SS-USCs) and rice-shaped USCs (RS-USCs) respectively. The two subpopulations showed similar clone-forming efficiency, while SS-USCs featured faster proliferation, higher motility, and greater potential for osteogenic and adipogenic differentiation, RS-USCs showed greater potential for chondrogenic differentiation. POU5F1 was strongly expressed in both subpopulations, but MYC was weakly expressed. Both subpopulations showed similar patterns of CD24, CD29, CD34, CD44, CD73, CD90 and CD105 expression, while a higher percentage of RS-USCs were positive for CD133. SS-USCs were positive for VIM, weakly positive for SLC12A1 and UMOD, and negative for KRT18, NPHS1, AQP1 and AQP2, indicating a renal mesenchyme origin; while RS-USCs are positive for VIM, partially positive for KRT18, NPHS1, AQP1, SLC12A1 and UMOD, and negative for AQP2, indicating a nephron tubule origin. The above results can facilitate understanding of the biological characteristics of subpopulations of USCs, and provide a basis for further research and applications of such cells.