Panoply™ Human RORC Knockdown Stable Cell Line

The expression and function of retinoic acid-related orphan receptors (RORA, B, and C) in pancreatic β cells are poorly understood. Here, researchers show that while RORA is the most highly expressed of the three RORs in human islet cells, RORC is the most highly expressed in INS-1 cells (832/13). Although RORA is highly expressed in human islets, particularly in muscle tissue, its expression is significantly reduced in rat INS-1 cells. Expression of RORB and RORC is significantly reduced in diabetic/hyperglycemic subjects compared with nondiabetic subjects. Furthermore, RORB expression positively correlates with insulin secretion and negatively correlates with HbA1c, while RORC expression negatively correlates with HbA1c. The expression pattern of RORA does not correlate with either parameter. Silencing RORB or RORC with siRNA in INS-1 (832/13) cells significantly downregulates insulin mRNA expression and secretion. These findings suggest that RORB and RORC are part of a molecular cascade that regulates insulin secretion in pancreatic β-cells. This provides insights into the potential therapeutic role of RORB and RORC genes in β-cell dysfunction in type 2 diabetes.

To investigate the effects of ROR receptors on glucose-stimulated insulin secretion, researchers generated RORB and RORC knockdown cells (Figure 1a). Silencing RORB or RORC expression significantly reduced glucose-stimulated insulin secretion after a 1-hour incubation with 16.7 mM glucose (Figures 1b-c). However, basal glucose-stimulated insulin secretion remained unchanged (Figures 1b-c). As shown in Figure 1d), the percentage of apoptosis in transfected cells cultured in the absence of cytokines was 3% while that in the presence of cytokines was 75%. The apoptotic potential of RORB or RORC knockdown cells was not significantly different from that of the negative control. This was further confirmed by MTT cell viability and cell proliferation data. Cell viability of RORB and RORC knockdown cells was not reduced compared to the negative control (Figure 1e). Furthermore, after 24 or 48 hours of culture, the proliferation response of RORB or RORC knockdown cells was unchanged compared to the negative control (Figure 1f).

Figure 1. Functional competence of INS-1 (832/13) cells following siRNA silencing of RORB and RORC genes. (Taneera J, et al., 2019)