RETRACTED: Typhae pollen polysaccharides protect hypoxia-induced PC12 cell injury via regulation of miR-34a/SIRT1

Abstract

<jats:p> This current research was performed to investigate the role of typhae pollen polysaccharides (TPP) in hypoxia-treated PC12 cell which was an in vitro cell model of cerebral ischemia. Hypoxia-treated cells were treated with TPP for 12 h. Cell viability and apoptosis were detected by 3-(4,5-dimethylthiazol-2-yl)-2 5-diphenyl-2H-tetrazolium bromide (MTT) assay and flow cytometry, respectively. Cell apoptotic proteins and PI3K/AKT and Ras/Raf/MEK/ERK signal pathway–associated proteins were also examined by western blot. Furthermore, abnormal expression of miR-34a and silent information regulator 1 (SIRT1) was achieved by transfection. Besides, the expression of miR-34a and SIRT1 was examined by quantitative real-time polymerase chain reaction (qRT-PCR). The expression of SIRT1 was detected by qRT-PCR and western blot. The relationship between miR-34a and SIRT1 was verified by luciferase assay. We found that TPP enhanced cell viability and inhibited apoptosis in hypoxia-treated PC12 cells. Moreover, TPP increased the accumulated levels of Bcl-2 while decreased expression of Bax, cleaved Caspase-3, and cleaved PARP. TPP downregulated miR-34a expression while induced by hypoxia. Further results showed that miR-34a overexpression reversed the results led by TPP in cell viability, apoptosis, and its related proteins. In addition, SIRT1 was upregulated by TPP and was verified to be a target of miR-34a. Silence of SIRT1 led to the opposite results led by TPP. In the end, TPP activated PI3K/AKT and Ras/Raf/MEK/ERK signal pathways. In conclusion, TPP plays important roles in regulating cell viability and apoptosis in hypoxia-treated PC12 cells via modulating miR-34a/SIRT1, as well as activating PI3K/AKT and Ras/Raf/MEK/ERK signal pathways. </jats:p>

Circular dumbbell miR‑34a‑3p and ‑5p suppresses pancreatic tumor cell‑induced angiogenesis and activates macrophages

“…It was observed that in the two pancreatic cancer cell lines transfected with db34a, the expression levels of bFGF and CCL5 were significantly increased. miR-34a-5p expression is known to be increased by the activation of the PI3K signaling pathway (51) and, notably, mir-34a-5p has been shown to suppress the PI3K signaling pathway (52)(53)(54)(55)(56). These contradictory observations indicates the possibility of the existence of a tight regulatory apparatus that is not yet clearly understood.…”

Sesquiterpene compound α-cyperone relieves the injury in neurons undergoing oxygen-glucose deprivation/reoxygenation

“…Rat pheochromocytoma PC12 has the general characteristics of neuroendocrine cells and is broadly used in neurophysiological research (Wang et al, 2020b). Hence, PC12 cells were subjected to oxygen-glucose deprivation/reoxygenation (OGD/R) to mimic I/R in vitro (Sun et al, 2018).…”