PK2/PKR1 signaling pathway participates in geniposide protection against diabetic nephropathy in mice / 中国中药杂志

This study aimed to investigate the effects of geniposide(GP) on the expression of prokineticin(PK2) and prokineticin receptor 1(PKR1) in db/db mice with diabetic nephropathy(DN), so as to explore how the PK2 signaling pathway participated in the pathological changes of DN and whether GP exerted the therapeutic effect through this signaling pathway. Male mice were randomly divided into four groups, namely db/m, db/db, db/db+GP, and db/m+GP groups, with five in each group. The mice in the db/db+GP and db/m+GP groups were gavaged with 150 mg·kg~(-1) GP for eight successive weeks. Afterwards, all the mice were sacrificed and the renal tissues were embedded. The morphological changes in glomerulus and renal tubules were observed by Masson and PAS staining. The expression levels of PK2, PKR1, and Wilm's Tumor Protein 1(WT_1) in podocytes were detected by immunohistochemistry, and the protein expression levels of PK2 and PKR1 in mouse kidney by Western blot. The morphological results showed serious glomerular and tubular fibrosis(Masson), high glomerular and tubular injury score(PAS), increased glomerular mesangial matrix, thickened basement membrane, exfoliated brush border of renal tubules, decreased WT_1 in glomerular podocytes, and massive loss of podocytes in the db/db group. After administration with GP, the glomerular and tubular fibrosis was alleviated, accompanied by improved glomerular basement membrane and renal tubule brush edge, and up-regulated WT_1. As revealed by further protein detection, in the db/db group, the expression levels of PK2 and PKR1 and p-Akt/Akt ratio declined, whereas the ratio of Bax/Bcl-2 rose. Ho-wever, PKR2 and p-ERK/ERK ratio did not change significantly. After administration with GP, the PK2 and PKR1 expression was elevated, and p-Akt/Akt ratio was increased. There was no obvious change in PKR2, Bax/Bcl-2 ratio, or p-ERK/ERK ratio. All these have demonstrated that GP improves the renal damage in DN mice, and PK2/PKR1 signaling pathway may be involved in such protection, which has provided reference for clinical treatment of DN with GP.

Prokineticin 2 mediates peripheral and central sensitization of somatic pain / 药学实践杂志

Prokineticin 2 (PK2) is a newly discovered chemokine, which participates in various physiological functions of the body by binding to receptors PKR1 and PKR2. PK signaling pathway is a newly discovered important regulatory pathway for the occurrence and maintenance of pain after tissue injury and nerve injury in recent years. It plays a key role in regulating injury-related nociceptive events and is a potential therapeutic target for many diseases. The activation of PKRs can induce pain sensation and participate in the sensitivity of pain receptors to different stimuli. The PK system (PKs and PKRs) is an important link involved in inflammation and pain transmission in immune cells. PK2 is involved in the regulation of pain perception by activating PKR1 and PKR2 on primary sensory neurons. In rat primary sensory neurons, PK2 also enhances gated ion channel current through the PKC signaling pathway, inhibits GABA-activated currents, and sensitizes purine nucleotide P2 receptor (P2X). This paper reviews the research progress of PK2 in physical pain. We hope to find new drugs for the treatment of inflammatory pain that target the PKs signaling pathway in future studies.