PNPLA3 148M/M Is More Susceptible to Palmitic Acid-Induced Endoplasmic Reticulum Stress-Associated Apoptosis in HepG2 Cells
Background. Patatin-like phospholipase domain-containing 3 (PNPLA3) is a major susceptibility gene for nonalcoholic fatty liver disease (NAFLD), and its rs738409 (I148M) polymorphism is associated with the occurrence and progression of NAFLD. Endoplasmic reticulum (ER) stress-related hepatocyte lipo...
| Main Authors: | , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Hindawi Limited
2023-01-01
|
| Series: | International Journal of Endocrinology |
| Online Access: | http://dx.doi.org/10.1155/2023/2872408 |
| _version_ | 1811158505986457600 |
|---|---|
| author | Yunzhi Chen Xuemei Yan Tian Wang Hongrong Deng Xiaojie Deng Fen Xu Hua Liang |
| author_facet | Yunzhi Chen Xuemei Yan Tian Wang Hongrong Deng Xiaojie Deng Fen Xu Hua Liang |
| author_sort | Yunzhi Chen |
| collection | DOAJ |
| description | Background. Patatin-like phospholipase domain-containing 3 (PNPLA3) is a major susceptibility gene for nonalcoholic fatty liver disease (NAFLD), and its rs738409 (I148M) polymorphism is associated with the occurrence and progression of NAFLD. Endoplasmic reticulum (ER) stress-related hepatocyte lipoapoptosis contributes to the progress of NAFLD. PNPLA3 is also known as a member of the calcium-independent phospholipase A2ε family, which can hydrolyze fatty acids to generate lysophosphatidylcholine (LPC) that induces ER stress-related hepatocyte lipoapoptosis. Whether the PNPLA3 risk genotype 148M/M is involved in more severe ER stress-associated lipoapoptosis is unclear. Methods. A PNPLA3148I knock-in HepG2 cell model was constructed based on HepG2 expressing PNPLA3 148M/M using the Cas9/sgRNA system. PNPLA3 148M/M, I/M, and I/I cells were treated with 0.3 mM palmitic acid (PA) for 24 h to induce lipid deposition. Cellular lipid deposition was detected by oil red staining. Apoptosis was observed by TUNEL. LPC was determined by ELISA, and the expression of PNPLA3, the ER stress marker Bip, molecules involved in the ER stress PERK/elF-2a pathway, and its downstream C/EBP homologous protein (CHOP)-mediated apoptotic pathway were detected by western blot. Results. The results showed no difference in PNPLA3 basal expression and basal hepatocyte lipid content between the three genotypes of cells. Lipid deposition and apoptosis were more severe in PNPLA3 148M/M and 148I/M cells than in I/I cells after PA treatment. PA-induced upregulation of protein expression of Bip, ER stress-responsive PERK pathway molecules p-PERK, p-eIF2α, CHOP, and CHOP-associated apoptotic molecules PUMA and Bax were more pronounced in PNPLA3 148M/M cells than in PNPLA3 148I/I cells. The basal LPC levels and the PA-treated increase of LPC levels in the cell culture supernatants did not differ between the three genotypic cells. Conclusion. PNPLA3 148M/M cells were more susceptible to PA-induced lipid deposition and ER stress-related apoptosis than 148I/I cells, and the proapoptotic susceptibility of PNPLA3 148M/M is independent of LPC. |
| first_indexed | 2024-04-10T05:25:41Z |
| format | Article |
| id | doaj.art-505aa736132643dda52e9d9c95156252 |
| institution | Directory Open Access Journal |
| issn | 1687-8345 |
| language | English |
| last_indexed | 2024-04-10T05:25:41Z |
| publishDate | 2023-01-01 |
| publisher | Hindawi Limited |
| record_format | Article |
| series | International Journal of Endocrinology |
| spelling | doaj.art-505aa736132643dda52e9d9c951562522023-03-08T00:00:18ZengHindawi LimitedInternational Journal of Endocrinology1687-83452023-01-01202310.1155/2023/2872408PNPLA3 148M/M Is More Susceptible to Palmitic Acid-Induced Endoplasmic Reticulum Stress-Associated Apoptosis in HepG2 CellsYunzhi Chen0Xuemei Yan1Tian Wang2Hongrong Deng3Xiaojie Deng4Fen Xu5Hua Liang6Department of Endocrinology and MetabolismDepartment of Endocrinology and MetabolismDepartment of Endocrinology and MetabolismDepartment of Endocrinology and MetabolismDepartment of Endocrinology and MetabolismDepartment of Endocrinology and MetabolismDepartment of Endocrinology and MetabolismBackground. Patatin-like phospholipase domain-containing 3 (PNPLA3) is a major susceptibility gene for nonalcoholic fatty liver disease (NAFLD), and its rs738409 (I148M) polymorphism is associated with the occurrence and progression of NAFLD. Endoplasmic reticulum (ER) stress-related hepatocyte lipoapoptosis contributes to the progress of NAFLD. PNPLA3 is also known as a member of the calcium-independent phospholipase A2ε family, which can hydrolyze fatty acids to generate lysophosphatidylcholine (LPC) that induces ER stress-related hepatocyte lipoapoptosis. Whether the PNPLA3 risk genotype 148M/M is involved in more severe ER stress-associated lipoapoptosis is unclear. Methods. A PNPLA3148I knock-in HepG2 cell model was constructed based on HepG2 expressing PNPLA3 148M/M using the Cas9/sgRNA system. PNPLA3 148M/M, I/M, and I/I cells were treated with 0.3 mM palmitic acid (PA) for 24 h to induce lipid deposition. Cellular lipid deposition was detected by oil red staining. Apoptosis was observed by TUNEL. LPC was determined by ELISA, and the expression of PNPLA3, the ER stress marker Bip, molecules involved in the ER stress PERK/elF-2a pathway, and its downstream C/EBP homologous protein (CHOP)-mediated apoptotic pathway were detected by western blot. Results. The results showed no difference in PNPLA3 basal expression and basal hepatocyte lipid content between the three genotypes of cells. Lipid deposition and apoptosis were more severe in PNPLA3 148M/M and 148I/M cells than in I/I cells after PA treatment. PA-induced upregulation of protein expression of Bip, ER stress-responsive PERK pathway molecules p-PERK, p-eIF2α, CHOP, and CHOP-associated apoptotic molecules PUMA and Bax were more pronounced in PNPLA3 148M/M cells than in PNPLA3 148I/I cells. The basal LPC levels and the PA-treated increase of LPC levels in the cell culture supernatants did not differ between the three genotypic cells. Conclusion. PNPLA3 148M/M cells were more susceptible to PA-induced lipid deposition and ER stress-related apoptosis than 148I/I cells, and the proapoptotic susceptibility of PNPLA3 148M/M is independent of LPC.http://dx.doi.org/10.1155/2023/2872408 |
| spellingShingle | Yunzhi Chen Xuemei Yan Tian Wang Hongrong Deng Xiaojie Deng Fen Xu Hua Liang PNPLA3 148M/M Is More Susceptible to Palmitic Acid-Induced Endoplasmic Reticulum Stress-Associated Apoptosis in HepG2 Cells International Journal of Endocrinology |
| title | PNPLA3 148M/M Is More Susceptible to Palmitic Acid-Induced Endoplasmic Reticulum Stress-Associated Apoptosis in HepG2 Cells |
| title_full | PNPLA3 148M/M Is More Susceptible to Palmitic Acid-Induced Endoplasmic Reticulum Stress-Associated Apoptosis in HepG2 Cells |
| title_fullStr | PNPLA3 148M/M Is More Susceptible to Palmitic Acid-Induced Endoplasmic Reticulum Stress-Associated Apoptosis in HepG2 Cells |
| title_full_unstemmed | PNPLA3 148M/M Is More Susceptible to Palmitic Acid-Induced Endoplasmic Reticulum Stress-Associated Apoptosis in HepG2 Cells |
| title_short | PNPLA3 148M/M Is More Susceptible to Palmitic Acid-Induced Endoplasmic Reticulum Stress-Associated Apoptosis in HepG2 Cells |
| title_sort | pnpla3 148m m is more susceptible to palmitic acid induced endoplasmic reticulum stress associated apoptosis in hepg2 cells |
| url | http://dx.doi.org/10.1155/2023/2872408 |
| work_keys_str_mv | AT yunzhichen pnpla3148mmismoresusceptibletopalmiticacidinducedendoplasmicreticulumstressassociatedapoptosisinhepg2cells AT xuemeiyan pnpla3148mmismoresusceptibletopalmiticacidinducedendoplasmicreticulumstressassociatedapoptosisinhepg2cells AT tianwang pnpla3148mmismoresusceptibletopalmiticacidinducedendoplasmicreticulumstressassociatedapoptosisinhepg2cells AT hongrongdeng pnpla3148mmismoresusceptibletopalmiticacidinducedendoplasmicreticulumstressassociatedapoptosisinhepg2cells AT xiaojiedeng pnpla3148mmismoresusceptibletopalmiticacidinducedendoplasmicreticulumstressassociatedapoptosisinhepg2cells AT fenxu pnpla3148mmismoresusceptibletopalmiticacidinducedendoplasmicreticulumstressassociatedapoptosisinhepg2cells AT hualiang pnpla3148mmismoresusceptibletopalmiticacidinducedendoplasmicreticulumstressassociatedapoptosisinhepg2cells |