1. Quantitative digital pathology reveals association of cell-specific PNPLA3 transcription with NAFLD disease activity
- Author
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Bynvant Sandhu, Misung Kim, Maria C. Perez Matos, Imad Nasser, Michelle Lai, Z. Gordon Jiang, Eva Csizmadia, Stephanie Tran, Alexander H. Zhong, and Mark A. Herman
- Subjects
medicine.medical_specialty ,Short Communication ,Chromosomal translocation ,Disease ,Biology ,03 medical and health sciences ,0302 clinical medicine ,COL1α ,Internal medicine ,Genotype ,Internal Medicine ,medicine ,Transcriptional regulation ,Immunology and Allergy ,lcsh:RC799-869 ,Gene ,RNAscope ,030304 developmental biology ,liver fibrosis ,0303 health sciences ,Messenger RNA ,collagen 1α ,Hepatology ,Fatty liver ,Gastroenterology ,NASH ,patatin-like phospholipase domain-containing protein 3 ,medicine.disease ,digestive system diseases ,3. Good health ,Endocrinology ,030211 gastroenterology & hepatology ,lcsh:Diseases of the digestive system. Gastroenterology ,non-alcoholic steatohepatitis ,Steatosis ,Non-alcoholic fatty liver disease - Abstract
Background & Aims The I148M variant (rs738409) in patatin-like phospholipase domain-containing protein 3 (PNPLA3) is by far the most important genetic determinant of non-alcoholic fatty liver disease (NAFLD). However, in the context of NAFLD, the transcriptional regulation of PNPLA3 in human liver cells is not known. In this study, we aimed to define the relationship between PNPLA3 transcription and disease characteristics of human NAFLD. Methods The abundance of PNPLA3 and collagen 1α (COL1α) transcripts was quantified in situ at single-cell resolution using RNAscope® in 87 patients with NAFLD. We examined the association of PNPLA3 and COL1α transcript levels with NAFLD disease severity, defined by histology. Results While the majority of PNPLA3 transcripts were found in hepatocytes, approximately 7% of PNPLA3-positive cells co-express COL1α, representing activated myofibroblasts. There is no association between the rs738409 genotype and the level of PNPLA3 transcript. The overall PNPLA3 transcript abundance is lower in zone 1 hepatocytes, patients with higher body mass index, and those with advanced liver fibrosis. The negative association between the PNPLA3 transcript levels and liver fibrosis is largely driven by COL1α-positive cells. A significant proportion of PNPLA3 mRNA is seen in the nucleus. The cytoplasmic-to-nuclear PNPLA3 mRNA ratio is inversely associated with NAFLD disease activity. Conclusions PNPLA3 transcript abundance and nuclear-to-cytoplasmic translocation are negatively associated with hepatic steatosis and NAFLD disease activity, while its abundance in activated myofibroblasts is inversely associated with the stage of liver fibrosis. Lay summary A genetic variant in patatin-like phospholipase domain-containing protein 3 (or PNPLA3) is the most important genetic determinant of non-alcoholic fatty liver disease (NAFLD). However, it is not known how transcriptional regulation of the PNPLA3 gene contributes to the disease characteristics of human NAFLD. Herein, we show that the mRNA levels of PNPLA3, particularly in the cytoplasm, are negatively associated with the severity of NAFLD in humans., Highlights • Relationships between PNPLA3 transcription and the severity of human non-alcoholic fatty liver disease was unknown. • PNPLA3 transcript abundance is negatively associated with hepatic steatosis and non-alcoholic fatty liver disease activity. • Nuclear-to-cytoplasmic translocation of PNPLA3 is also negatively associated with non-alcoholic fatty liver disease severity. • PNPLA3 transcript abundance in activated myofibroblasts is inversely associated with the stage of liver fibrosis.
- Published
- 2019