Conformational studies of biaryl-bridged seven-membered lactones with a quaternary carbon center.

We show the synthesis and conformational studies of a series of 7,7-disubstituted-dibenzo[b,d]oxepin-6(7H)-ones that feature biaryl-bridged seven-membered lactones with a quaternary carbon center, in which the larger substituents prefer the axial positions. Further studies on the crystal structures and DFT calculations revealed that the high selectivity observed is attributed to the volume of substituents.

Vascular Aging in Ischemic Stroke.

Cellular senescence, a permanent halt in cell division due to stress, spurs functional and structural changes, contributing to vascular aging characterized by endothelial dysfunction and vascular remodeling. This process raises the risk of ischemic stroke (IS) in older individuals, with its mechanisms still not completely understood despite ongoing research efforts. In this review, we have analyzed the impact of vascular aging on increasing susceptibility and exacerbating the pathology of IS. We have emphasized the detrimental effects of endothelial dysfunction and vascular remodeling influenced by oxidative stress and inflammatory response on vascular aging and IS. Our goal is to aid the understanding of vascular aging and IS pathogenesis, particularly benefiting older adults with high risk of IS.

BACH1 regulates the differentiation of vascular smooth muscle cells from human embryonic stem cells via CARM1-mediated methylation of H3R17.

The role of BACH1 in the process of vascular smooth muscle cell (VSMC) differentiation from human embryonic stem cells (hESCs) remains unknown. Here, we find that the loss of BACH1 in hESCs attenuates the expression of VSMC marker genes, whereas overexpression of BACH1 after mesoderm induction increases the expression of VSMC markers during in vitro hESC-VSMC differentiation. Mechanistically, BACH1 binds directly to coactivator-associated arginine methyltransferase 1 (CARM1) during in vitro hESC-VSMC differentiation, and this interaction is mediated by the BACH1 bZIP domain. BACH1 recruits CARM1 to VSMC marker gene promoters and promotes VSMC marker expression by increasing H3R17me2 modification, thus facilitating in vitro VSMC differentiation from hESCs after the mesoderm induction. The increased expression of VSMC marker genes by BACH1 overexpression is partially abolished by inhibition of CARM1 or the H3R17me2 inhibitor TBBD in hESC-derived cells. These findings highlight the critical role of BACH1 in hESC differentiation into VSMCs by CARM1-mediated methylation of H3R17.

Differences in CpG island distribution between exogenous and endogenous jaagsiekte sheep retrovirus strains.

The jaagsiekte sheep retrovirus (JSRV), belonging to the betaretrovirus genus of the retroviridae family, includes both exogenous and endogenous jaagsiekte sheep retroviruses (exJSRV and enJSRV, respectively). At the proviral genome level, exJSRV and enJSRV strains have a high degree of similarity with their main variation regions being the LTR, gag, and env genes. In this study, for the first time, we investigated and compared the distribution of CpG islands between these enJSRV and exJSRV strains. Specifically, we analyzed a total of 42 full-length JSRV genomic sequences obtained from the GenBank® database to identify CpG islands in the exJSRV and enJSRV genomes using the MethPrimer software. Our results showed that the CpG islands in the two JSRV strains were mainly distributed in the LTR, gag, and env genes. In exJSRVs, 66.66% (6/9), 33.33% (3/9), and 100% (9/9) of the sequences presented at least one CpG island in LTR, gag, env genes, respectively, and for enJSRVs, 84.84% (28/33), 57.57% (19/33), and 96.96% (32/33) of the sequences presented at least one CpG island in the LTR, gag, and env genes. These findings suggested that the distribution, length, and genetic traits of CpG islands were different for the exJSRV and enJSRV strains. In future, it would be necessary to demonstrate the biological significance of CpG islands within these genes in exJSRV and enJSRV genomes. This will enhance understanding regarding the potential role of CpG islands in epigenetic regulation.

The Effect of Intramolecular Hydrogen Bonds on the Rotational Barriers of the Biaryl C-C Axis.

Axially chiral compounds are attracting more attention recently. Although hydrogen bonds are reported as a vital weak force that influences the properties of compounds, the effect of intramolecular hydrogen bonds on the atropisomerization of the Caryl -Caryl single bonds has not yet been well quantitatively investigated. Here, a series of axially chiral biaryl compounds were synthesized to study the effect of hydrogen bonds on the rotational barriers of the biaryl C-C axis. Experimental studies demonstrated that the rotational barrier of hydrogen bonding biaryl 9 was significantly lower (46.7 kJ mol-1 ) than biaryl 10 without hydrogen bonds. Furthermore, theoretical studies revealed that the intramolecular hydrogen bond stabilized the transition state (TS) of tri-ortho-substituted biaryl 9, relieving the steric repulsion in the TS. We believe that this study will provide chemists with a deeper understanding of the atropisomerization process of axially chiral biaryl compounds.

A Novel Strategy for Liposomal Drug Separation in Plasma by TiO2 Microspheres and Application in Pharmacokinetics.

Purpose: Liposomes are nano-scale materials with a biofilm-like structure. They have excellent biocompatibility and are increasingly useful in drug delivery systems. However, the in vivo fate of liposomal drugs is still unclear because existing bioanalytical methods for quantitation of total and liposomal-encapsulated drugs have limits. A novel strategy for liposomal-encapsulated drug separation from plasma was developed via the specific coordinate binding interaction of TiO2 microspheres with the phosphate groups of liposomes. Methods: Liposomal-encapsulated docetaxel was separated from plasma by TiO2 microspheres and analyzed by the UPLC-MS/MS method. The amount of TiO2, pH of the dilutions, plasma dilution factors and incubation time were optimized to improve extraction recovery. The characterization of the adsorption of liposome-encapsulated drugs by TiO2 microspheres was observed by electron microscopy. For understanding the mechanism, pseudo-first and the pseudo-second order equations were proposed for the adsorption process. The study fully validated the method for quantitation of liposomal-encapsulated in plasma and the method was applied to the pharmacokinetic study of docetaxel liposomes. Results: The encapsulated docetaxel had a concentration range of 15-4000 ng/mL from the plasma sample using a TiO2 extraction method. Successful method validation proved the method was sensitive, selective and stable, and was suitable for quantitation of docetaxel liposomes in plasma samples. Extraction recovery of this method was higher than that of SPE method. As shown in electron microscopy, the liposomes adsorbed on TiO2 microspheres were intact and there was no drug leakage. The study proposed pseudo-first and the pseudo-second order equations to facilitate the adsorption of liposomal drugs with TiO2 microspheres. The proposed strategy supports the pharmacokinetic study of docetaxel liposomes in rats. Conclusion: TiO2 extraction method was stable, reproducible, and reliable for quantitation of encapsulated docetaxel. Because of versatility of lipids, it is expected to a universal bioanalysis method for the pharmacokinetic study of liposomes.

Strain-Induced Indirect-to-Direct Bandgap Transition, Photoluminescence Enhancement, and Linewidth Reduction in Bilayer MoTe2.

Two-dimensional (2D) layered materials provide an ideal platform for engineering electronic and optical properties through strain control because of their extremely high mechanical elasticity and sensitive dependence of material properties on mechanical strain. In this paper, a combined experimental and theoretical effort is made to investigate the effects of mechanical strain on various spectral features of bilayer MoTe2 photoluminescence (PL). We found that bilayer MoTe2 can be converted from an indirect to a direct bandgap material through strain engineering, resulting in a photoluminescence enhancement by a factor of 2.24. Over 90% of the PL comes from photons emitted by the direct excitons at the maximum strain applied. Importantly, we show that strain effects lead to a reduction of the overall linewidth of PL by as much as 36.6%. We attribute the dramatic decrease of linewidth to a strain-induced complex interplay among various excitonic varieties such as direct bright excitons, trions, and indirect excitons. Our experimental results on direct and indirect exciton emission features are explained by theoretical exciton energies that are based on first-principles electronic band structure calculations. The consistent theory-experimental trend shows that the enhancement of PL and the reduction of linewidth are the consequences of the increasing direct exciton contribution with the increase of strain. Our results demonstrate that strain engineering can lead to a PL quality of the bilayer MoTe2 comparable to that of the monolayer counterpart. The additional benefit of a longer emission wavelength makes the bilayer MoTe2 more suitable for silicon-photonics integration due to the reduced silicon absorption.

Substitution of gp120 C4 region compensates for V3 loss-of-fitness mutations in HIV-1 CRF01_AE co-receptor switching.

HIV-1 infection is mediated by a viral envelope subsequently binding to CD4 receptor and two main coreceptors, CCR5 (R5) for primary infection and CXCR4 (X4) in chronic infection. Switching from R5 to X4 tropism in HIV-1 infection is associated with increased viral pathogenesis and disease progression. The coreceptor switching is mainly due to variations in the V3 loop, while the mechanism needs to be further elucidated. We systematically studied the determinant for HIV-1 coreceptor switching by substitution of the genes from one R5 and one X4 pseudoviruses. The study results in successfully constructing two panels of chimeric viruses of R5 to X4 forward and X4 to R5 reverse switching. The determinants for tropism switching are the combined substitution of the V3 loop and C4 region of the HIV-1 envelope. The possible mechanism of the tropism switching includes two components, the V3 loop to enable the viral envelope binding to the newly switched coreceptor and the C4 region, to compensate for the loss of fitness caused by deleterious V3 loop mutations to maintain the overall viral viability. The combined C4 and V3 substitution showed at least an eightfold increase in replication activity compared with the pseudovirus with only V3 loop substitution. The site-directed mutations of N425R and S440-I442 with charged amino acids could especially increase viral activity. This study could facilitate HIV-1 phenotype surveillance and select right entry inhibitor, CCR5 or CXCR4 antagonists, for antiviral therapy.

Immune cell-derived extracellular vesicular microRNAs induce pancreatic beta cell apoptosis.

Background: Type 1 diabetes mellitus (T1DM) is an autoimmune disease caused by an autoimmune response against pancreatic islet ß cells. Increasing evidence indicates that specific microRNAs (miRNAs) from immune cells extracellular vesicles are involved in islet ß cells apoptosis. Methods: In this study, the microarray datasets GSE27997 and GSE137637 were downloaded from the Gene Expression Omnibus (GEO) database. miRNAs that promote islet ß cells apoptosis in T1DM were searched in PubMed. We used the FunRich tool to determine the miRNA expression in extracellular vesicles derived from immune cells associated with islet ß cell apoptosis, of which we selected candidate miRNAs based on fold change expression. Potential upstream transcription factors and downstream target genes of candidate miRNAs were predicted using TransmiR V2.0 and starBase database, respectively. Results: Candidate miRNAs expressed in extracellular vesicles derived from T cells, pro-inflammatory macrophages, B cells, and dendritic cells were analyzed to identify the miRNAs involved in ß cells apoptosis. Based on these candidate miRNAs, 25 downstream candidate genes, which positively regulate ß cell functions, were predicted and screened; 17 transcription factors that positively regulate the candidate miRNAs were also identified. Conclusions: Our study demonstrated that immune cell-derived extracellular vesicular miRNAs could promote islet ß cell dysfunction and apoptosis. Based on these findings, we have constructed a transcription factor-miRNA-gene regulatory network, which provides a theoretical basis for clinical management of T1DM. This study provides novel insights into the mechanism underlying immune cell-derived extracellular vesicle-mediated islet ß cell apoptosis.

Triazine-Porphyrin-Based Hyperconjugated Covalent Organic Framework for High-Performance Photocatalysis.

Covalent organic frameworks (COFs) with porphyrins as structural units are a new kind of porous organic polymers, which have a regular and ordered structure, abundant porosity, and good stability. In the past, the construction of porphyrin COFs was generally synthesized by routes such as a Schiff base reaction. Here, we report a new COF structure by linking the porphyrin with the triazine ring. Using a cyano group-terminated porphyrin as a structural unit precursor, a new triazine-porphyrin hyperconjugated COF (TA-Por-sp2-COF) was constructed through the cyano group's self-polymerization. The extension of porphyrin units in two directions that stemmed from the cyano group at para-positions accounts for the establishment of a highly ordered two-dimensional topological structure. Attributing to the collaboration of electron-donating and withdrawing blocks for photo-induced carrier separation and adequate porosity for mass diffusion, this hyperconjugated system showed high photocatalytic performance in organic reactions such as the aerobic coupling reaction of benzylamine and thioanisole selective oxidation.

Unique profile of predominant CCR5-tropic in CRF07_BC HIV-1 infections and discovery of an unusual CXCR4-tropic strain.

CRF07_BC is one of the most prevalent HIV-1 strains in China, which contributes over one-third of the virus transmissions in the country. In general, CRF07_BC is associated with slower disease progression, while the underlying mechanisms remain unclear. Our study focused on envelope proteins (Env) and its V3 loop which determine viral binding to co-receptors during infection of cells. We studied a large dataset of 3,937 env sequences in China and found that CRF07_BC had a unique profile of predominantly single CCR5 tropism compared with CCR5 and CXCR4 dual tropisms in other HIV-1 subtypes. The percentages of the CXCR4-tropic virus in B (3.7%) and CRF01_AE (10.4%) infection are much higher than that of CRF07_BC (0.1%), which is supported by median false-positive rates (FPRs) of 69.8%, 25.5%, and 13.4% for CRF07_BC, B, and CRF01_AE respectively, with a cutoff FPR for CXCR4-tropic at 2%. In this study, we identified the first pure CXCR4-tropic virus from one CRF07_BC-infected patient with an extremely low CD4+T cell count (7 cells/mm3). Structural analysis found that the V3 region of this virus has the characteristic 7T and 25R and a substitution of conserved "GPGQ" crown motif for "GPGH". This study provided compelling evidence that CRF07_BC has the ability to evolve into CXCR4 strains. Our study also lay down the groundwork for studies on tropism switch, which were commonly done for other HIV-1 subtypes, for the long-delayed CRF07_BC.

Self-assembled BPIV3 nanoparticles can induce comprehensive immune responses and protection against BPIV3 challenge by inducing dendritic cell maturation in mice.

Bovine parainfluenza virus type 3 (BPIV3) is one of the most important viral respiratory pathogens of cattle. No specific therapies are available for BPIV3 infection; vaccination is one of the most effective ways to prevent BPIV3 infection. We therefore prepared the self-assembled BPIV3 nanoparticles by genetically fusing the ectodomain of BPIV3 haemagglutinin-neuraminidase (HN) (HNex) to the NH2 terminus of ferritin (HNex-RFNp) using a baculovirus expression system. It was found that HNex-RFNp-induced bone marrow-derived dendritic cell (BMDC) maturation through the upregulated expression of surface molecules (MHC II, CD80, CD86, and CD40), increased the secretion of inflammatory cytokines (IL-6, IL-12, TNF-α, and IFN-γ), and reduced antigen phagocytosis and T cell activation capacity. HNex-RFNp positively regulated IκBα and NF-κB (p65) phosphorylation and facilitated NF-κB (p65) translocation into the nuclei of mature BMDCs. Incubating RFNp-treated BMDCs with TLR4 and NF-κB (p65) inhibitors, suppressed surface molecule expression as well as pro-inflammatory cytokine production and IκBα and NF-κB (p65) activities. The BPIV3 HNex protein induced BMDC maturation to some extent but was significantly weaker than HNex-RFNp. We found that HNex-RFNp induced a higher titre of specific antibodie, haemagglutinin inhibition (HI) antibody, and virus neutralisation (VN) antibody, and a comprehensive cellular immune response. We examined protection against BPIV3 challenge in a mouse model. Pathological changes were not observed in the lungs of HNex-RFNp-vaccinated mice. Levels of BPIV3 RNA and virus titres in the lungs and trachea were significantly lower in the HNex-RFNp, than HNex, inactivated BPIV3, and PBS groups. In summary, HNex-RFNp elicited better immunogenicity than HNex or inactivated BPIV3 and could be developed as an effective vaccine to protect against BPIV3 infection.

HIV-1 genetic diversity a challenge for AIDS vaccine development: a retrospective bibliometric analysis.

BACKGROUND: Despite recent advances in human immunodeficiency virus-1 (HIV-1) prevention, a fast, safe, and effective vaccine will probably be necessary to end the HIV/AIDS pandemic. This study was conducted to evaluate global research trends and map the key bibliometric indices in HIV-1 genetic diversity from 1998 to 2021. METHODS: A comprehensive online search was conducted in the Web of Science Core Collection database to retrieve published literature on HIV-1 genetic diversity. Key bibliometric indicators were calculated and evaluated using HistCiteTM, Bibliometrix: An R-tool, and VOSviewer software for windows. RESULTS: A total of 2,060 documents written by 9,201 authors and published in 250 journals were included in the final analysis. Year 2012 was the most productive year with 121 (5.87%) publications. The most prolific author was Shao Yiming (n = 74, 3.59%) from Chinese Center for Disease Control and Prevention. The United States of America was the highly contributing and influential country (n = 681, 33.05%). AIDS Research and Human Retroviruses was the most productive journal (n = 562, 27.2%). Network visualization shows that HIV-1 was the most widely used author keyword. CONCLUSION: This study provides global research trends and detailed information on HIV-1 genetic diversity. The amount of scientific literature on HIV-1 genetic diversity research has rapidly increased in the last two decades. The maximum number of articles on HIV-1 genetic diversity was published in developed countries; therefore, a scientific research collaboration among researchers and institutes in low-income countries should be promoted and supported.

Erratum: Application of systematic nursing in patients with maniac access of bipolar disorder and its impact on treatment compliance and quality of life.

[This corrects the article on p. 6929 in vol. 13, PMID: 34306445.].

HIV-1 CRF07_BC transmission dynamics in China: two decades of national molecular surveillance.

ABSTRACTBy analyzing an unprecedentedly large, longitudinal HIV-1 CRF07_BC sequence dataset collected from China in the past two decades, we sought to build CRF07_BC lengthwise transmission networks, and understand its transmission dynamics. We divided CRF07_BC into two clusters based on phylogenetic analysis and an estimation of the pairwise genetic distance at 0.7%. Of 6213 sequences, 3607 (58.1%) linked to ≥1 other sequence. CRF07_BC was divided into two clusters: 07BC_O and 07BC_N. The 07BC_O is the original CRF07_BC, circulating in people who inject drugs (PWID) and heterosexuals, predominantly in southwestern and northwestern provinces of China. The 07BC_N is a new cluster, identified mostly in men having sex with men (MSM) in the northern provinces of China. Bayesian analysis indicates that CRF07_BC has experienced two phases of exponential growth, which was first driven by 07BC_O then 07BC_N. Compared to 07BC_O, the proportion of the parameter of population transmission risk (TR) of 07BC_N has risen constantly. The power-law function analyses reveal that 07BC_N has increased over years with higher degree. In 07BC_N, only 13.16% of MSM were linked to other risk groups, but these links represent 41.45%, 54.25%, and 55.07% of links among heterosexual females, heterosexual males, and male PWID respectively. This study indicates that CRF07_BC has evolved into two clusters in China, and their distributions are distinct across risk groups and geographical regions. 07BC_N shows a greater risk of transmission, and has gradually replaced 07BC_O. Furthermore, the results show that strengthening the MSM interventions could lower the rapidity of 07BC_N transmission in all risk groups.

Doxorubicin-Near infrared dye conjugate induces immunogenic cell death to enhance cancer immunotherapy.

Cancer immunotherapy often fails to result in a favorable outcome owing to poor activation of immune response, the immunosuppressive tumor microenvironment, and systemic toxicity. In this study, indocyanine green (ICG) was conjugated with doxorubicin (DOX) using a hydrazone linker (DOX-ICG). Results of our in vitro and in vivo studies indicated that DOX-ICG could trigger powerful immunogenic cell death (ICD) of tumor cells. Moreover, its use in combination with immune checkpoint inhibitors could effectively inhibit both primary and abscopal tumors growth and suppress tumor metastasis. Therefore, this simple, safe, and efficient prodrug shows great potential for use in photo-activated chemo-immunotherapy.

Application of systematic nursing in patients with maniac access of bipolar disorder and its impact on treatment compliance and quality of life.

OBJECTIVE: To explore the application of systematic nursing in patients with maniac access of bipolar disorder and its impact on treatment compliance and quality of life. METHODS: Using a random number table method, 91 patients with manic episodes of bipolar disorder were divided into a control group (n=46, received conventional nursing) and an observation group (n=45, combined with systematic care including health education, ward environment, mental health nursing, and rehabilitation training, mental state assessment and family and social support). The treatment compliance of Morisky Medication Adherence Scale (MMAS), the manic state of Bech-Rafaelsdn Mania Rating Scale (BRMS), the mental state of Hamilton Depression Scale (HAMA) and Hamilton Depression Scale (HAMD), the quality of life of Generic Quality of Life Inventory-74 (GQOLI-74), the self-efficacy of Strategies Used by Patients to Promote Health (SUPPH), and the cognitive function of the Chinese Version of the Wechsler Adult Intelligence Scale Revised (WAIS-RC) before and 3 months after intervention were compared. RESULTS: After intervention, the BRMS scores of the patients in both groups were significantly decreased, and those in the observation group were lower than those in the control group (all P<0.05). After intervention, the MMAS scores of patients in the observation group were significantly higher than those in the control group (P<0.05). After intervention, the scores of GQOLI-74, SUPPH and WAIS-RC in the observation group were significantly higher than those in the control group (all P<0.05). After intervention, the scores of HAMA and HAMD in both groups decreased, and those in the observation group were lower than those in the control group (all P<0.05). CONCLUSION: Systematic nursing for patients with maniac access of bipolar disorder can clearly relieve their bad moods, control their manic state, and improve their self-efficacy, quality of life and treatment compliance.

Clofazimine: A Promising Inhibitor of Rabies Virus.

With an almost 100% mortality rate, rabies virus (RABV) infection is a global concern. Limited post-exposure prophylaxis and lack of an effective treatment necessitate novel antiviral therapies against RABV. Here, using a high-throughput screening (HTS) method developed in our lab, 11 candidates with anti-RABV activity were identified from a library of 767 clinical drugs. Clofazimine (CFZ), an anti-leprosy drug, displayed an EC50 of 2.28 µM, and SI over 967 against RABV. Investigations into the underlying mechanisms revealed that CFZ targeted viral membrane fusion at the early stages of virus replication. Moreover, CFZ and Clofazimine salicylates (CFZS) exhibited elevated survival rates in vivo, compared with the positive control T-705. Thus, this study revealed CFZ as a promising drug against RABV infection.

A Novel Type-I Interferon Family, Bovine Interferon-Chi, Is Involved in Positive-Feedback Regulation of Interferon Production.

Interferon-chi (IFN-χ) is a type of function-unknown IFN. IFN-χ in bovines (BoIFN-χ) has evolved as a multigene family. This family comprises four IFN-χ subtypes, two of which are functional genes, which we demonstrated to (i) have antiviral and antiproliferative activities, (ii) be highly sensitive to trypsin, and (iii) remain stable with changes in pH and temperature. BoIFN-χ is a key intermediate in antiviral response, PAbs against BoIFN-χs could downregulate the transcriptional activation of ISGs induced by poly(I:C), and BoIFN-χs could be induced upon virus infection at the early and late phase. Additionally, BoIFN-χs bind with type-I IFN receptors, induce transcription of interferon regulatory factor 7 (IRF7), interferon-stimulated genes (ISGs), and type-I IFNs as well as myxovirus resistance protein 1 (Mx1) expression. Expression of ISGs and activation of IFN-stimulated response element (ISRE) induced with BoIFN-χs could be downregulated significantly by the Janus kinase (JAK) 1 and signal transducers and activators of transcription (STAT) 1 inhibitor. The promoters of BoIFN-ß, nuclear factor-kappa B, and ISRE could be activated with BoIFN-χs, and the BoIFN-χ promoter could be activated by other type-I IFNs. Overall, BoIFN-χ could be induced with virus infection and signal through the JAK-STAT pathway to form a positive-feedback regulation of IFN production. These findings may facilitate further research on the role of IFN-χ in innate immune responses.

The IFN-γ-induced immunoproteasome is suppressed in highly pathogenic porcine reproductive and respiratory syndrome virus-infected alveolar macrophages.

Highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) evades cytotoxic T lymphocyte (CTL) responses through interactions between viral Nsp1α and Nsp4 and ß2 M heavy and light chains, respectively, of swine leukocyte antigen class (SLA)-I. However, whether the immunoproteasome (i-proteasome) complex, which is an important component of the antigen delivery pathway that functions by mediating peptide production, is also affected by viral infection is unknown. In this study, we investigated the effects of HP-PRRSV (HuN4-F5) infection on IFN-γ-induced i-proteasome expression using a cell culture system (alveolar macrophages, AMs). We found that this virus inhibited the expression of IFN-γ-induced i-proteasome subunits LMP2, LMP7, and MECL-1 at the mRNA and protein level. In addition, expression levels of the i-proteasome regulatory subunits PSME1 and PSME2 in the HP-PRRSV HuN4-F5-infected group were also significantly decreased compared to those in the uninfected group. However, there was no significant difference in the expression of proteasome subunits PSMB5, PSMB6, and PSMB7 between HP-PRRSV HuN4-F5-infected and uninfected groups. This study provides insight into the mechanisms underlying immune regulation by HP-PRRSV; specifically, this virus affects the antigen-processing machinery by suppressing IFN-γ-induced i-proteasome expression in infected AMs.