Transcriptomic signatures responding to PKM2 activator TEPP-46 in the hyperglycemic human renal proximal epithelial tubular cells

Abstract

Pyruvate kinase M2 (PKM2), as the terminal and last rate-limiting enzyme of the glycolytic pathway, is an ideal enzyme for regulating metabolic phenotype. PKM2 tetramer activation has shown a protective role against diabetic kidney disease (DKD). However, the molecular mechanisms involved in diabetic tubular have not been investigated so far. In this study, we performed transcriptome gene expression profiling in human renal proximal tubular epithelial cell line (HK-2 cells) treated with 25 mM high D-glucose (HG) for 7 days before the addition of 10 μM TEPP-46, an activator of PKM2 tetramerization, for a further 1 day in the presence of HG. Afterwards, we analyzed the differentially expressed (DE) genes and investigated gene relationships based on weighted gene co-expression network analysis. The results showed that 2,902 DE genes were identified (adjusted P-value ≤ 0.05), where 2,509 DE genes (86.46%) were co-expressed in the key module. Four extremely downregulated DE genes (HSPA8, HSPA2, HSPA1B, and ARRB1) and three extremely upregulated DE genes (GADD45A, IGFBP3, and SIAH1) enriched in the downregulated endocytosis (hsa04144) and upregulated p53 signaling pathway (hsa04115), respectively, were validated by qRT-PCR experiments. The qRT-PCR results showed that the relative expression levels of HSPA8 [adjusted P-value = 4.45 × 10-34 and log2(FC) = -1.12], HSPA2 [adjusted P-value = 6.09 × 10-14 and log2(FC) = -1.27], HSPA1B [adjusted P-value = 1.14 × 10-11 and log2(FC) = -1.02], and ARRB1 [adjusted P-value = 2.60 × 10-5 and log2(FC) = -1.13] were significantly different (P-value < 0.05) from the case group to the control group. Furthermore, the interactions and predicted microRNAs of the key genes (HSPA8, HSPA2, HSPA1B, and ARRB1) were visualized in networks. This study identified the key candidate transcriptomic biomarkers and biological pathways in hyperglycemic HK-2 cells responding to the PKM2 activator TEPP-46 that can highlight a possibility of PKM2 tetramerization reshaping the interplay among endocytic trafficking through the versatile networks of Hsp70s and rewiring the crosstalk between EGFR signal transduction circuits and metabolic stress to promote resilience, which will be valuable for further research on PKM2 in DKD.

KITENIN promotes aerobic glycolysis through PKM2 induction by upregulating the c-Myc/hnRNPs axis in colorectal cancer

“…It has also been shown to facilitate angiogenesis of extracellular maxtrix PKM2 in cancer cells [ 82 ]. The findings from another study, which identified important prospective transcriptome indicators and biological pathways in hyperglycemic HK-2 cells responsive to the PKM2 activator TEPP-46, underscore the need for more investigation into the signaling mechanisms regulating EGFR and metabolic stress [ 83 ].…”

Editorial: Advances in the research of diabetic nephropathy, volume II

“…Recently, TEPP-2 was shown to restore hyperglycemia-induced glomerular and tubular metabolic phenotypes, further inhibiting fibrotic progression in DKD. Wang et al cultured HK-2 cells under sustained high glucose exposure (7 days) with (case group) or without (control group) the addition of TEPP-46 for another 1 day and analyzed the genome-wide transcriptome data from the case and control groups (7). Four extremely downregulated DE genes (HSPA8, HSPA2, HSPA1B, and ARRB1) and three extremely upregulated differentially expressed genes (GADD45A, IGFBP3, and SIAH1) are involved in decreased endocytosis (hsa04144) and the enhanced p53 signaling pathway (hsa04115), respectively.…”

“…Pyruvate kinase muscle isozyme M2 (PKM2) forms both dimers and tetramers ( 7 ). In proliferation, the dimeric state of PKM2 promotes anabolism, such as in the polyol pathway, pentose phosphate pathway, and uronic acid pathway ( 7 ). In contrast, the tetrameric state of PKM2 promotes ATP synthesis and catabolism.…”

“…In contrast, the tetrameric state of PKM2 promotes ATP synthesis and catabolism. The PKM2 activator TEPP-2 reduces PKM2 dimerization ( 7 ). Recently, TEPP-2 was shown to restore hyperglycemia-induced glomerular and tubular metabolic phenotypes, further inhibiting fibrotic progression in DKD.…”

“…Four extremely downregulated DE genes (HSPA8, HSPA2, HSPA1B, and ARRB1) and three extremely upregulated differentially expressed genes (GADD45A, IGFBP3, and SIAH1) are involved in decreased endocytosis (hsa04144) and the enhanced p53 signaling pathway (hsa04115), respectively. The researchers concluded that PKM2 tetramerization induced by TEPP-46 in hyperglycemic HK-2 cells reshaped the interplay among endocytic trafficking, dynamics of protein folding/unfolding, and the autophagy/lysosome system through the versatile networks of Hsp70s ( 7 ). Thus, these results partly provide a clue to resolve the mechanism by which PKM2 activators improve renal function.…”