Pseudorabies virus upregulates low-density lipoprotein receptors to facilitate viral entry

Pseudorabies virus (PRV) is the causative agent of Aujeszky's disease in pigs. The low-density lipoprotein receptor (LDLR) is a transcriptional target of the sterol-regulatory element-binding proteins (SREBPs) and participates in the uptake of LDL-derived cholesterol. However, the involvement of LDLR in PRV infection has not been well characterized. We observed an increased expression level of LDLR mRNA in PRV-infected 3D4/21, PK-15, HeLa, RAW264.7, and L929 cells. The LDLR protein level was also upregulated by PRV infection in PK-15 cells and in murine lung and brain. The treatment of cells with the SREBP inhibitor, fatostatin, or with SREBP2-specific small interfering RNA prevented the PRV-induced upregulation of LDLR expression as well as viral protein expression and progeny virus production. This suggested that PRV activated SREBPs to induce LDLR expression. Furthermore, interference in LDLR expression affected PRV proliferation, while LDLR overexpression promoted it. This indicated that LDLR was involved in PRV infection. The study also demonstrated that LDLR participated in PRV invasions. The overexpression of LDLR or inhibition of proprotein convertase subtilisin/kexin type 9 (PCSK9), which binds to LDLR and targets it for lysosomal degradation, significantly enhanced PRV attachment and entry. Mechanistically, LDLR interacted with PRV on the plasma membrane, and pretreatment of cells with LDLR antibodies was able to neutralize viral entry. An in vivo study indicated that the treatment of mice with the PCSK9 inhibitor SBC-115076 promoted PRV proliferation. The data from the study indicate that PRV hijacks LDLR for viral entry through the activation of SREBPs.IMPORTANCEPseudorabies virus (PRV) is a herpesvirus that primarily manifests as fever, pruritus, and encephalomyelitis in various domestic and wild animals. Owing to its lifelong latent infection characteristics, PRV outbreaks have led to significant financial setbacks in the global pig industry. There is evidence that PRV variant strains can infect humans, thereby crossing the species barrier. Therefore, gaining deeper insights into PRV pathogenesis and developing updated strategies to contain its spread are critical. This study posits that the low-density lipoprotein receptor (LDLR) could be a co-receptor for PRV infection. Hence, strategies targeting LDLR may provide a promising avenue for the development of effective PRV vaccines and therapeutic interventions.

[An evaluation method for physical properties of medicinal film and its application in screening film formulation of Trillium tschonoskii total saponins]

At present, the evaluation methods for pharmaceutical properties of Chinese medicinal films have many problems, such as poor objectivity for the indexes and no quantitative and standardized evaluation methods. This study established a new method using three important physical property parameters, i.e., flow index, weight loss rate, and elongation rate, which were closely related to the pharmaceutical properties of films. On this basis, the above parameters were taken as indicators to optimize the film formulation of Trillium tschonoskii total saponins and verify the feasibility and suitability of the established method and parameters in formulation optimization. A self-made flow distance detection device and a viscometer were used to measure and characterize the fluidity, where the flow index refers to the ratio of the flow distance per unit time to the viscosity. The weight loss rate was measured by the 3 M transpore~(TM) surgical tape. The film-forming property was characterized by the weight loss rate of the sample within a certain period of time. An electronic tension machine was employed to measure the elongation rate after drying, which was used to characterize the ductility of the film. The results showed that the established method for the determination of flow index, weight loss rate, and elongation rate was stable and reliable. The optimal film formulation of T. tschonoskii total saponins could be obtained by optimization with those indicators. As demonstrated, the above evaluation indicators(flow index, weight loss rate, and elongation rate) can guide the optimization and design of formulation, and the new evaluation method constructed based on this shows a good application prospect in formulation optimization and formulation quality evaluation of medicinal films.

[Research Progress of Pleckstrin Homology Like Domain Family A Member 1 in Tumor]

Pleckstrin homology like domain family A member 1(PHLDA1) is also known as T-cell death-associated gene 51 (TDAG51).Studies have demonstrated that the abnormal expression of PHLDA1 is closely associated with the formation,development,and metastasis of tumors.We summarized the latest research advances in the structure and biological properties of PHLDA1,as well as the roles of PHLDA1 in multiple malignanttumors such as breast cancer,cancer,liver gastric cancer,liver cancer,melanoma,and osteosarcoma,aiming to comprehensively reveal the significance of PHLDA1 in the clinical diagnosis of tumors.

[Effects of low molecular weight organic acids on redox reactions of mercury]

To study the effects of the main component of vegetation root exudates-low molecular weight organic acids on the redox reactions of mercury, laboratory experiments were conducted to investigate the roles of tartaric, citric, and succinic acid in the redox reactions of mercury, and to analyze their interaction mechanism. The results indicated that tartaric acid significantly stimulated the mercury reduction reaction, while citric acid had inhibitory effect. Succinic acid improved the reduction rate at low concentration, and inhibited the reaction at high concentration. The mercury reduction rate by tartaric acid treatment was second-order with respect to Hg2+ concentration, ranging from 0.0014 L x (ng x min)(-1) to 0.005 6 L x (ng x min)(-1). All three organic acids showed a capacity for oxidating Hg(0) in the early stage, but the oxidized Hg(0) was subsequently reduced. The oxidation capacity of the three organic acids was in the order of citric acid > tartaric acid > succinic acid.