Caerulein-induced pancreatitis augments the expression and phosphorylation of collapsin response mediator protein 4

Regulation of Microtubule Stability in Pulmonary Microvascular Endothelial Cells in Rats with Severe Acute Pancreatitis: Qingyi Decoction is a Potential CDK5 Inhibitor

Purpose

Explore the therapeutic effects and regulatory mechanism of Qingyi Decoction (QYD) on severe acute pancreatitis (SAP) associated acute lung injury (ALI).

Methods

We identified the constituents absorbed into the blood of QYD based on a network pharmacological strategy. The differentially expressed genes from the GEO database were screened to identify the critical targets of QYD treatment of SAP-ALI. The SAP-ALI rat model was constructed.Some methods were used to evaluate the efficacy and mechanism of QYD in treating SAP-ALI. LPS-stimulated pulmonary microvascular endothelial cell injury simulated the SAP-induced pulmonary endothelial injury model. We further observed the therapeutic effect of QYD and CDK5 plasmid transfection on endothelial cell injury.

Results

18 constituents were absorbed into the blood, and 764 targets were identified from QYD, 25 of which were considered core targets for treating SAP-ALI. CDK5 was identified as the most critical gene. The results of differential expression analysis showed that the mRNA expression level of CDK5 in the blood of SAP patients was significantly up-regulated compared with that of healthy people. Animal experiments have demonstrated that QYD can alleviate pancreatic and lung injury inflammatory response and reduce the upregulation of CDK5 in lung tissue. QYD or CDK5 inhibitors could decrease the expression of NFAT5 and GEF-H1, and increase the expression of ACE-tub in SAP rat lung tissue. Cell experiments proved that QYD could inhibit the expression of TNF-α and IL-6 induced by LPS. Immunofluorescence results suggested that QYD could alleviate the cytoskeleton damage of endothelial cells, and the mechanism might be related to the inhibition of CDK5-mediated activation of NFAT5, GEF-H1, and ACE-tub.

Conclusion

CDK5 has been identified as a critical target for pulmonary endothelial injury of SAP-ALI. QYD may partially alleviate microtubule disassembly by targeting the CDK5/NFAT5/GEF-H1 signaling pathway, thus relieving SAP-induced pulmonary microvascular endothelial cell injury.

Collapsin response mediator protein 4 enhances the radiosensitivity of colon cancer cells through calcium‑mediated cell signaling

Radiation therapy is an effective treatment against various types of cancer, but some radiation‑resistant cancer cells remain a major therapeutic obstacle; thus, understanding radiation resistance mechanisms is essential for cancer treatment. In this study, we established radiation‑resistant colon cancer cell lines and examined the radiation‑induced genetic changes associated with radiation resistance. Using RNA‑sequencing analysis, collapsin response mediator protein 4 (<em>CRMP4</em>) was identified as the candidate gene associated with radiation sensitivity. When cells were exposed to radiation, intracellular Ca²⁺ influx, collapse of mitochondrial membrane potential, and cytochrome c release into the cytosol were increased, followed by apoptosis induction. Radiation treatment‑ or Ca²⁺ ionophore A23187‑induced apoptosis was significantly inhibited in <em>CRMP4</em>‑deficient cells, including radiation‑resistant or <em>CRMP4</em>‑shRNA cell lines. Furthermore, treatment of <em>CRMP4</em>‑deficient cells with low levels (&lt;5 µM) of BAPTA‑AM, a Ca²⁺ chelator, resulted in radiation resistance. Conversely, Ca²⁺ deficiency induced by a high BAPTA‑AM concentration (&gt;10 µM) resulted in higher cell death in the <em>CRMP4</em>‑depleted cells compared to <em>CRMP4</em>‑expressing control cells. Our results suggest that <em>CRMP4</em> plays an important role in Ca²⁺‑mediated cell death pathways under radiation exposure and that CRMP4 may be a therapeutical target for colon cancer treatment.

Low Incidence of High-Grade Pancreatic Intraepithelial Neoplasia Lesions in a Crmp4 Gene-Deficient Mouse Model of Pancreatic Cancer

Pancreatic intraepithelial neoplasia (PanIN), the most common premalignant lesion of the pancreas, is a histologically well-defined precursor to invasive pancreatic ductal adenocarcinoma (PDAC). However, the molecular mechanisms underlying the progression of PanINs have not been fully elucidated. Previously, we demonstrated that the expression of collapsin response mediator protein 4 (CRMP4) in PDAC was associated with poor prognosis. The expression of CRMP4 was also augmented in a pancreatitis mouse model. However, the role of CRMP4 in the progression of PanIN lesions remains uncertain. In the present study, we examined the relationship between CRMP4 expression and progression of PanIN lesions using genetically engineered mouse models. PanIN lesions were induced by peritoneal injection of the cholecystokinin analog caerulein in LSL-KRAS^G12D; Pdx1-Cre (KC-Crmp4 wild-type, WT) mice and LSL-KRAS^G12D; Pdx1-Cre; Crmp4^−/− (KC-Crmp4 knockout, KO) mice. We analyzed pancreatic tissue sections from these mice and evaluated PanIN grade by hematoxylin and eosin staining. CRMP4 expression was examined and the cellular components assessed by immunohistochemistry using antibodies against CRMP4, CD3, and α-smooth muscle actin (SMA). The incidence of high-grade PanIN in KC-Crmp4 WT mice was higher than that in KC-Crmp4 KO animals. CRMP4 was expressed not only in epithelial cells but also in αSMA-positive cells in stromal areas of PanIN lesions. The CRMP4 expression in stromal areas correlated with PanIN grade in WT mice. These results suggested that the expression of CRMP4 in stromal cells may underlie the incidence or progression of PanIN.