PRMT1 methylation of WTAP promotes multiple myeloma tumorigenesis by activating oxidative phosphorylation via m6A modification of NDUFS6

Epigenetic modifications play important roles during the pathogenesis of multiple myeloma (MM). Herein, we found that protein arginine methyltransferase 1 (PRMT1) was highly expressed in MM patients, which was positively correlated with MM stages. High PRMT1 expression was correlated with adverse prognosis in MM patients. We further showed that silencing PRMT1 inhibited MM proliferation and tumorigenesis in vitro and in vivo. Mechanistically, we revealed that the knockdown of PRMT1 reduced the oxidative phosphorylation (OXPHOS) of MM cells through NDUFS6 downregulation. Meanwhile, we identified that WTAP, a key component of the m6A methyltransferase complex, was methylated by PRMT1, and NDUFS6 was identified as a bona fide m6A target of WTAP. Finally, we found that the combination of PRMT1 inhibitor and bortezomib synergistically inhibited MM progression. Collectively, our results demonstrate that PRMT1 plays a crucial role during MM tumorigenesis and suggeste that PRMT1 could be a potential therapeutic target in MM.

Dynamic Changes in Serum Cytokine Profile in Rats with Severe Acute Pancreatitis

Background and Objectives: Most published research has only investigated a single timepoint after the onset of severe acute pancreatitis (SAP), meaning that they have been unable to observe the relationship between the dynamic changes in cytokines and SAP progression. In this study, we attempted to reveal the relationship between dynamic changes in cytokine expression levels and SAP disease progression and the relationship between cytokines, using continuous large-scale cytokine detection. Materials and Methods: Seventy rats were randomly assigned to control (Con), sham operation (SO) and SAP groups. The SAP group was randomly allocated to five subgroups at 3, 6, 9, 12 and 15 h after the operation. In the SAP group, 5% sodium taurocholate was injected retrograde into the pancreatic bile duct. Animals in the SO group received a similar incision, a turning over of the pancreas. Control animals did not receive any treatment. We observed the survival, ascites fluid amount, pancreatic histopathological scores and serum amylase activity of SAP rats. We used the cytokine microarray to simultaneously detect 90 cytokines and the dynamic changes in one experiment and to analyze the correlation between cytokine expression and disease progression. Results: The mortality of SAP rats increased with an increase in time. Serum amylase activity, pancreatic histopathological scores and ascites fluid amount were time-dependent. Compared with normal rats, 69 cytokines in SAP rats were significantly changed for at least one timepoint, and 49 cytokines were significantly changed at different timepoints after SAP induction. The changes in inflammatory cytokines were significantly upregulated at 6 and 9 h and 12 h and then significantly decreased. Conclusions: The trend of cytokine expression in SAP rats was not consistent with the disease progression. The cytokine-cytokine receptor interaction and MAPK signal's dominant cytokines were always highly expressed at various time points over the course of SAP.

Improvement of gut microbiome and intestinal permeability following splenectomy plus pericardial devascularization in hepatitis B virus-related cirrhotic portal hypertension

The gut microbiome is an essential component of the intestinal mucosal barrier, critical in regulating intestinal permeability. Microbiome dysbiosis and intestinal permeability changes are commonly encountered conditions in patients with cirrhosis and are closely related to its development and further complications. However, alterations in the gut microbiome and intestinal permeability in chronic hepatitis B virus (HBV) patients with cirrhotic portal hypertension after undergoing a splenectomy plus pericardial devascularization (SPD) have not been investigated. This study recruited 22 patients who were measured against themselves on the study parameters before and after an SPD, along with 20 healthy controls. Methodologically, fecal samples were collected for gut microbiome analysis by 16S ribosomal DNA sequencing, and peripheral blood samples were obtained to examine the liver function and intestinal permeability. This study showed that the community structure of the gut microbiomes in patients before the SPD exhibited obvious differences from those in the healthy control group. They also exhibited a decreased bacterial community richness, increased intestinal permeability, and enhanced inflammation compared with the healthy controls. These issues were further aggravated two weeks after the SPD. There was also evidence of significantly higher abundances of Streptococcaceae, Enterobacteriaceae, and Enterococcaceae than those in the healthy control group. However, 12 months after the surgery, 12 of the 16 patient-associated genera recovered, of which 10 reached normal levels. Additionally, the microbiome diversity increased; the bacterial composition was back to a level similar to the healthy controls. Liver function, intestinal permeability, and inflammation levels all improved compared with preoperative levels. Furthermore, correlation analyses indicated that the five recovered bacterial taxa and the Shannon diversity index were correlated with several improved clinical indicators. Altogether, the improvements in the liver function and intestinal permeability in HBV-related cirrhotic patients may be related to the restoration of the gut microbiome after an SPD.

Splenectomy provides protective effects against CLP-induced sepsis by reducing TRegs and PD-1/PD-L1 expression

The role of the spleen in sepsis is still controversial. Therefore, we investigated the effect of the spleen on sepsis-induced immune dysfunction in C57BL/6 mice subjected to caecal ligation and puncture (CLP). Changes in different immune cells and apoptotic cells in the spleen and peripheral blood were observed 4, 24 and 48 h after CLP. Then, we determined that 48 h following CLP was the most significant period of immunosuppression. Next, we divided the mice into four groups: control, CLP, CLP + spx (splenectomy 48 h after CLP) and spx + CLP (splenectomy surgery two weeks before CLP). Compared with the CLP mice, the CLP + spx and spx + CLP mice had improved survival rates and organ injuries, increased expression of inflammatory factors, a decreased proportion of regulatory T cells (Tregs), and reduced expression of the genes involved in the programmed cell death 1 and its ligand 1 (PD1-PDL1) pathway in immune cells and T-cell immunoglobulin-mucin domain 3 (Tim 3) and Galectin9 in the liver and lungs after 72 h in late-phase sepsis. In addition, the expression of PD-1 was significantly reduced in T cells in spx + CLP mice, and the expression of PD-L1 in myeloid-derived suppressor cells (MDSCs) was reduced in the CLP + spx group, especially in macrophages. These findings suggested that splenectomy could protect septic mice from exhaustion of immune cells by reducing the proliferation of Treg cells and expression of the PD-1/PD-L1 axis in immune cells during the immunosuppressive stage of sepsis. Splenectomy could also reduce liver and lung injuries possibly via the Tim 3 and/or Galectin-9 axis. The spleen is an important regulator of the occurrence and development of sepsis, which provides a new perspective to improve the prognosis of sepsis by regulating the spleen.

Emodin and baicalein inhibit sodium taurocholate-induced vacuole formation in pancreatic acinar cells

AIM

To investigate the effects of combined use of emodin and baicalein (CEB) at the cellular and organism levels in severe acute pancreatitis (SAP) and explore the underlying mechanism.

METHODS

SAP was induced by retrograde infusion of 5% sodium taurocholate into the pancreatic duct in 48 male SD rats. Pancreatic histopathology score, serum amylase activity, and levels of tumour necrosis factor alpha (TNF-α), interleukin 6 (IL-6), and IL-10 were determined to assess the effects of CEB at 12 h after the surgery. The rat pancreatic acinar cells were isolated from healthy male SD rats using collagenase. The cell viability, cell ultrastructure, intracellular free Ca²⁺ concentration, and inositol (1,4,5)-trisphosphate receptor (IP₃R) expression were investigated to assess the mechanism of CEB.

RESULTS

Pancreatic histopathology score (2.07 ± 1.20 vs 6.84 ± 1.13, P < 0.05) and serum amylase activity (2866.2 ± 617.7 vs 5241.3 ± 1410.0, P < 0.05) were significantly decreased in the CEB (three doses) treatment group compared with the SAP group (2.07 ± 1.20 vs 6.84 ± 1.13, P < 0.05). CEB dose-dependently reduced the levels of the pro-inflammatory cytokines IL-6 (466.82 ± 48.55 vs 603.50 ± 75.53, P < 0.05) and TNF-α (108.04 ± 16.10 vs 215.56 ± 74.67, P < 0.05) and increased the level of the anti-inflammatory cytokine IL-10 (200.96 ± 50.76 vs 54.18 ± 6.07, P < 0.05) compared with those in the SAP group. CEB increased cell viability, inhibited cytosolic Ca²⁺ concentration, and significantly ameliorated intracellular vacuoles and IP₃ mRNA expression compared with those in the SAP group (P < 0.05). There was a trend towards decreased IP₃R protein in the CEB treatment group; however, it did not reach statistical significance (P > 0.05).

CONCLUSION

These results at the cellular and organism levels reflect a preliminary mechanism of CEB in SAP and indicate that CEB is a suitable approach for SAP treatment.

Mesenchymal stem cells inhibited development of lung cancer induced by chemical carcinogens in a rat model

Mesenchymal stem cells (MSCs) may play a significant role in carcinogenesis; however, data have shown that MSCs can both promote and inhibit tumor growth. We investigated the effect of MSCs on the development of lung cancer in a rat model. Bone marrow-derived MSCs were isolated from male Wistar rats and fluorescently labeled. Genotoxic carcinogens 3-methylcholanthrene (MCA) and diethylnitrosamine (DEN) were instilled into the left lung lobes of female rats to induce tumors. Labeled male MSCs were infused into the female rats via tail vein, and the rats were sacrificed on days 3 and 7. MSC survival and distribution were detected by PCR and fluorescence, respectively. Labeled MSCs aggregated at the injection site in the left lobe (MCA/DEN-treated) on day 3 but not the untreated right lobe. Survival of the MSCs in vivo was confirmed by detection of the male SRY gene in lung tissues by PCR at day 3; however, by day 7, lung tissues were SRY-negative. Next, carcinogen-treated rats were divided into two groups and infused with normal MSCs (experimental group) or PBS (control group) every week for 10 weeks, then sacrificed. Cell proliferation in lung tissues was calculated by Ki67 and PCNA expression. Eighty-percent (8/10) of rats in the control group had tumors, while none of the rats in the experimental group had tumors. There was no difference in cell proliferation in lung tissues between the groups. Therefore, bone marrow-derived MSCs prevented development of carcinogen-induced lung cancer in a rat model. Additional studies are needed to determine mechanism.