Objective:To explore the protective effect and mechanism of scutellarin (Scu) on sepsis associated-acute kidney injury (SA-AKI).Methods:① In vivo experiment: 36 male C57BL/6 mice were divided into normal saline (NS) control group, lipopolysaccharide (LPS) induced SA-AKI model group (LPS group), 20 mg/kg Scu control group (Scu 20 control group), and 5, 10, 20 mg/kg Scu pretreatment groups by random number table with 6 mice in each group. The SA-AKI model was reproduced by intraperitoneal injection of 10 mg/kg LPS. The NS control group was injected with NS intraperitoneally. The Scu pretreatment groups were intraperitoneally injected with different doses of Scu every day before LPS injection for 1 week. Scu 20 control group was injected with 20 mg/kg Scu for 1 week. After 24 hours of LPS treatment, mice in each group were sacrificed, kidney tissues were collected, and kidney injury was detected by hematoxylin-eosin (HE) staining. Western blotting was used to detect the protein expression levels of nuclear factor-κB (NF-κB) signaling pathway related molecules, apoptosis-related proteins and cysteine-rich protein 61-connective tissue growth factor-nephroblastoma overexpressed gene 1 (CCN1). ② In vitro experiment: human renal tubular epithelial cell line HK-2 was cultured in vitro and used for experiment when the cells fused to 80%. In the cells without LPS treatment and after 100 g/L LPS treatment, pcDNA3.1-CCN1 and small interfering RNA (siRNA) CCN1 sequence were transfected to overexpress and inhibit CCN1 expression, respectively, to observe whether CCN1 was involved in NF-κB signaling pathway activation and apoptosis. In addition, 100g/L LPS and 20 μmol/L Scu were added into HK-2 cells transfected with and without CCN1 siRNA to investigate the mechanism of protective effect of Scu on LPS-induced HK-2 cells injury. Results:① The results of in vivo experiment: the renal function of SA-AKI mice induced by LPS was significantly decreased, and had kidney histological damage and severely damaged renal tubules. Scu could alleviate renal function and histological damage in a dose-dependent manner. Western blotting results showed Scu could reduce the protein expression of NF-κB signaling pathway related molecules and CCN1 in the renal tissue, and had a significant alleviating effect on apoptosis, indicating that CCN1 was involved in NF-κB signaling pathway activation and apoptosis. ② The results of in vitro experiment: in HK-2 cells not treated with LPS, CCN1 overexpression had no effect on apoptosis related protein and pro-inflammatory factors of NF-κB signaling pathway. In HK-2 cells treated with LPS, overexpression of CCN1 significantly inhibited the mRNA expressions of interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α) and monocyte chemoattractant protein-1 (MCP-1), with significant differences as compared with cells stimulated only by LPS [IL-1β mRNA (2 -ΔΔCT): 3.20±0.57 vs. 4.88±0.69, TNF-α mRNA (2 -ΔΔCT): 2.99±0.44 vs. 5.00±0.81, MCP-1 mRNA (2 -ΔΔCT): 2.81±0.50 vs. 5.41±0.75, all P < 0.05], and the apoptosis-related protein was significantly down-regulated. However, when siRNA was used to inhibit the expression of CCN1, the mRNA expressions of pro-inflammatory factors were significantly increased as compared with cells stimulated only by LPS [IL-1β mRNA (2 -ΔΔCT): 6.01±1.13 vs. 4.88±0.69, TNF-α mRNA (2 -ΔΔCT): 5.15±0.86 vs. 5.00±0.81, all P < 0.05], and apoptosis-related protein was significantly up-regulated. In the LPS-induced HK-2 cells, the mRNA expressions of pro-inflammatory factors were significantly down-regulated after Scu treatment as compared with cells stimulated only by LPS [IL-1β mRNA (2 -ΔΔCT) : 2.55±0.50 vs. 6.15±1.04, TNF-α mRNA (2 -ΔΔCT): 2.58±0.40 vs. 3.95±0.52, MCP-1 mRNA (2 -ΔΔCT): 2.64±0.44 vs. 6.21±0.96, all P < 0.05], and apoptosis-related protein was also significantly reduced. When the expression of CCN1 was inhibited by siRNA, the protective effect of Scu on cells was weakened, which showed that the mRNA expressions of pro-inflammatory factors in cells was significantly up-regulated compared with the cells without inhibition of CCN1 expression [IL-1β mRNA (2 -ΔΔCT): 5.34±0.76 vs. 2.55±0.50, TNF-α mRNA (2 -ΔΔCT): 3.66±0.54 vs. 2.58±0.40, MCP-1 mRNA (2 -ΔΔCT): 5.15±0.79 vs. 2.64±0.44, all P < 0.05], and the expression of apoptosis related protein was also significantly up-regulated. Conclusions:Scu could protect the renal function in SA-AKI mice, and the protective effect is associated with NF-κB signaling pathway and CCN1. Thus, Scu could alleviate LPS-induced kidney injury by regulating the NF-κB signaling pathway.

Objective:To investigate the impact of exogenous lactate on the replication of dengue virus type 2 (DENV-2) in Raw264.7 cells, mouse bone marrow-derived macrophages (BMDMs) and THP-1 cells and explore its association with cell activation.Methods:BMDMs from BALB/c mouse bone marrow were prepared and evaluated by flow cytometry to detect the proportion of F4/80 + CD11b + cells. Glucose transporter type 1 (GLUT1), hexokinase 2 (HK2), and monocarboxylate transporters 4 (MCT4) expression at mRNA level in BMDMs at different time points after DENV-2 infection were measured by qRT-PCR. The content of lactate in the culture supernatants was quantified via colorimetric assay. CCK-8 assay was used to evaluate the impacts of different concentrations of lactate on the viability of Raw264.7 cells, BMDMs, and THP-1 cells. qRT-PCR was used to detect the expression of DENV-2 E gene, TGF-β, CD86, retinoic acid-inducible gene Ⅰ (RIG-Ⅰ), IFN-β, interferon-stimulated gene 15 (ISG15), and ISG56 at mRNA level in cells infected with DENV-2 at different MOIs in the presence of different concentrations of lactate. Meanwhile, flow cytometry was used to analyze the expression of CD86 and CD206. Results:The percentage of BMDMs was (87.53±1.66)%. GLUT1 expression at mRNA level exhibited a decrease in BMDMs at 24 h after DENV-2 (MOI=3) infection following a transient increase at 12 h ( P<0.05), while HK2 expression at mRNA level was higher that than in blank control and inactivated DENV-2 infection groups at 12, 24, and 36 h ( P<0.01). Besides, there was an increase in both MCT4 mRNA level and the content of lactate in culture supernatants at 24 h after DENV-2 (MOI=1.5) infection ( P<0.05). The viability of the three types of cells remained above 80% when the concentration of lactate was 31.25 mmol/L. Lactate at the concentration of 35 mmol/L increased the expression of the DENV E gene at mRNA level in DENV-2-infected BMDMs at MOI=1 or MOI=2 ( P<0.05). Besides, it promoted the expression of DENV E gene at mRNA level in Raw264.7 and THP-1 cells ( P<0.001) as well as the expression of CD163, TGF-β, RIG-Ⅰ, IFN-β, ISG15 and ISG56 at mRNA level in BMDMs at MOI=1.5, but inhibited the expression of CD86 at mRNA level in BMDMs ( P<0.05). It also up-regulated CD206 protein expression ( P<0.01) and down-regulated CD86 protein expression ( P>0.05) in BMDMs. Conclusions:Exogenous lactate enhances DENV-2 replication in both human- and murine-derived macrophages and that might correlate with M2 macrophage polarization.

The emergence of SARS-CoV-2 variants of concern and repeated outbreaks of coronavirus epidemics in the past two decades emphasize the need for next-generation pan-coronaviral therapeutics. Drugging the multi-functional papain-like protease (PLpro) domain of the viral nsp3 holds promise. However, none of the known coronavirus PLpro inhibitors has been shown to be in vivo active. Herein, we screened a structurally diverse library of 50,080 compounds for potential coronavirus PLpro inhibitors and identified a noncovalent lead inhibitor F0213 that has broad-spectrum anti-coronaviral activity, including against the Sarbecoviruses (SARS-CoV-1 and SARS-CoV-2), Merbecovirus (MERS-CoV), as well as the Alphacoronavirus (hCoV-229E and hCoV-OC43). Importantly, F0213 confers protection in both SARS-CoV-2-infected hamsters and MERS-CoV-infected human DPP4-knockin mice. F0213 possesses a dual therapeutic functionality that suppresses coronavirus replication via blocking viral polyprotein cleavage, as well as promoting antiviral immunity by antagonizing the PLpro deubiquitinase activity. Despite the significant difference of substrate recognition, mode of inhibition studies suggest that F0213 is a competitive inhibitor against SARS2-PLpro via binding with the 157K amino acid residue, whereas an allosteric inhibitor of MERS-PLpro interacting with its 271E position. Our proof-of-concept findings demonstrated that PLpro is a valid target for the development of broad-spectrum anti-coronavirus agents. The orally administered F0213 may serve as a promising lead compound for combating the ongoing COVID-19 pandemic and future coronavirus outbreaks.
Animals ; Coronavirus Papain-Like Proteases/antagonists & inhibitors* ; Cricetinae ; Humans ; Mice ; Pandemics ; SARS-CoV-2/enzymology* ; COVID-19 Drug Treatment