Yuning Sun

Minute virus of canines (MVC) is an autonomous canine parvovirus that causes severe pathological outcomes, including embryo mortality, spontaneous abortion, and congenital malformations in neonatal puppies. Although MVC infection has been shown to induce host cell cycle arrest and apoptosis, the underlying regulatory mechanisms that coordinate cell proliferation and control apoptotic responses during viral replication remain poorly understood. Sirtuin 1 (SIRT1) is an NAD⁺-dependent deacetylase that plays a critical role in regulating cell cycle progression, DNA damage responses, and apoptosis. However, its involvement in MVC infection has not been fully elucidated. Herein, we show that MVC infection markedly upregulates the mRNA and protein expression levels of SIRT1 in a time-dependent manner. MVC infection activates the SIRT1-p53 signaling axis and modulates the acetylation status of p53. In addition, MVC alters the subcellular distribution of SIRT1, promoting its nuclear translocation and colocalization with the viral protein VP2. Functional analyses demonstrated that pharmacological activation of SIRT1 enhanced the viability of MVC-infected WRD cells (virus-tropic cell), promoting viral replication, prolonging S-phase arrest, and reducing apoptosis. Conversely, inhibition of SIRT1 produced the opposite effects, which were closely associated with regulation of the SIRT1-p53 signaling axis. Moreover, SIRT1 knockdown accelerated apoptosis and attenuated S-phase arrest, whereas SIRT1 overexpression further strengthened S-phase retention. Collectively, our findings identify the SIRT1-p53 signaling axis as an important regulator of cell cycle progression and apoptosis during MVC infection, highlighting SIRT1 as a key host factor that supports viral replication and persistence and a potential target for antiviral intervention.

The pathogenesis underlying diabetic peripheral neuropathy (DPN) remains largely elusive. Due to current unsatisfactory therapeutic approaches, new strategies for the control of DPN are needed. The present study was designed to assess whether inulin could serve as a potential neuroprotection against DPN in diverse stages of diabetes. Leptin receptor-mutant db/db mice were used as a model for DPN to dynamically assess the effects of inulin on DPN in diverse diabetic groups. According to blood glucose, the mice were randomly divided into prediabetes group (PDM group), inulin treated prediabetes group (INU/PDM group), diabetes group (DM group) and inulin treated diabetes group (INU/DM group). After 6 weeks of treatment, we found that inulin supplementation attenuated the neuropathic phenotypes in PDM and DM, including mechanical allodynia, thermal hyperalgesia and nerve conduction. Furthermore, inulin administration remarkably suppressed the levels of pro-inflammatory IL-6, TNF-α, and IL-17A in diverse diabetic groups with DPN, but increased an anti-inflammatory IL-10 in INU/PDM group, suggesting that dietary inulin intervention may suppress the DPN inflammation in different diabetic stages. Moreover, inulin supplementation markedly reduced the circulating LPS translocation. Metabolomics analysis revealed that inulin treatment significantly modulated the levels of 8 stage-specific metabolites; notably, it increased anti-inflammatory, anti-diabetic and neuroprotective metabolites taurine and dodecanoic acid in prediabetic mice, while decreasing pro-inflammatory mediators including oleamide and adrenic acid. In diabetic mice, inulin elevated metabolites including methylation (S-Adenosylmethionine), glucose homeostasis (glucose 6-phosphate), N-acetyl-L-phenylalanine and quinate. These metabolites are implicated in pathways such as bile acid metabolism, fatty acid oxidation, and neurotransmitter regulation, suggesting that inulin may exert neuroprotective effects by restoring metabolic homeostasis in a stage-dependent manner. Furthermore, rectification of gut dysbiosis by dietary inulin administration, with a major impact on increasing intestinal beneficial bacteria |( Bacteroides and Cyanobacteria ) and decreasing pro-inflammatory bacteria ( Ruminiclostridium_6 , Mucispirillum, Deferribacteres and Tenericutes ), exerted a close and complex interactions with metabolites, inflammatory factors, and peripheral neuropathic indicators. Collectively, dietary inulin intervention ameliorated DPN via reshaping gut microbial metabolism and suppressing inflammation, which may potentially provide an effective and safe therapeutics for the control of the disease.

Minute virus of canines (MVC), which is a member of the Bocaparvovirus genus, is a non-enveloped, single-stranded DNA virus that causes respiratory and gastrointestinal disease in canines, as well as causing infertility and fetal death in pregnant dogs. The non-structural small protein NP1 of bocaparvoviruses is a unique feature that distinguishes the bocaparvovirus subfamily from other parvovirus subfamilies. In the life cycle of the MVC, NP1 plays an indispensable role in viral DNA replication and pre-mRNA processing. Currently, there is a paucity of studies reporting the characterization of host cell proteins interacting with NP1 during MVC replication. In this study, we screened and identified host cell proteins interacting with MVC-NP1 through immunoprecipitation (IP) combined with liquid chromatography and tandem mass spectrometry (LC-MS/MS) analysis; MCM7 (Mini-chromosome Maintenance Protein 7) has been identified and confirmed to interact directly with NP1 through its N-terminal domain. Furthermore, functional studies reveal that MCM7 is essential in MVC replication. The knockdown of MCM7 decreased the expression of this MVC protein significantly, as well as suppressing MVC replication by arresting the cell cycle in the G0/G1 phase during infection. Conversely, up-regulating MCM7 can rehabilitate the expression of MVC proteins, as well as supporting MVC replication. In conclusion, this study elucidates the interaction between the NP1 protein of MVC and the host factor MCM7, demonstrating that MCM7 is a key factor in the replication process of MVC. These findings provide a potential target for future antiviral therapy.

The Minute Virus of Canines (MVC), belonging to the genus Bocaparvovirus within the family Parvoviridae, is associated with enteritis and embryonic infection in neonatal canines. Viral attachment to host cells is a critical step in infection, and viral protein 2 (VP2) as an important structural protein of MVC influences host selection and infection severity. Nevertheless, little is known about the interaction between VP2 protein and host cells. In this study, we identified that VP2 directly interacts with the kinase domain of RhoA-associated protein kinase 1 (ROCK1) by using mass spectrometry and immunoprecipitation approach and demonstrated that the RhoA/ROCK1/myosin light chain 2 (MLC2) signaling pathway was activated during the early stage of MVC infection in Walter Reed canine cell/3873D (WRD) cells. Further studies indicated that RhoA/ROCK1-mediated phosphorylation of MLC2 triggers the contraction of the actomyosin ring, disrupts tight junctions, and exposes the tight junction protein Occludin, which facilitates the interaction between VP2 and Occludin. Specific inhibitors of RhoA and ROCK1 restored the MVC-induced intracellular translocation of Occludin and the increase in cell membrane permeability. Moreover, the two inhibitors significantly reduced viral protein expression and genomic copy number. Collectively, our study provides the first evidence that there is a direct interaction between the structural protein VP2 of MVC and ROCK1, and that the tight junction protein Occludin can serve as a potential co-receptor for MVC infection, which may offer new targets for anti-MVC strategies.

Histone modifications function in both cellular and viral gene expression. However, the roles of acetyltransferases and histone acetylation in parvoviral infection remain poorly understood. In the current study, we found the histone deacetylase (HDAC) inhibitor, trichostatin A (TSA), promoted the replication and transcription of parvovirus minute virus of canines (MVC). Notably, the expression of host acetyltransferases KAT5, GTF3C4, and KAT2A was increased in MVC infection, as well as H4 acetylation (H4K12ac). KAT5 is not only responsible for H4K12ac but also crucial for viral replication and transcription. The viral nonstructural protein NS1 interacted with KAT5 and enhanced its expression. Further study showed that Y44 in KAT5, which may be tyrosine-phosphorylated, is indispensable for NS1-mediated enhancement of KAT5 and efficient MVC replication. The data demonstrated that NS1 interacted with KAT5, which resulted in an enhanced H4K12ac level to promote viral replication and transcription, implying the epigenetic addition of H4K12ac in viral chromatin-like structure by KAT5 is vital for MVC replication. IMPORTANCE: Parvoviral genomes are chromatinized with host histones. Therefore, histone acetylation and related acetyltransferases are required for the virus to modify histones and open densely packed chromatin structures. This study illustrated that histone acetylation status is important for MVC replication and transcription and revealed a novel mechanism that the viral nonstructural protein NS1 hijacks the host acetyltransferase KAT5 to enhance histone acetylation of H4K12ac, which relies on a potential tyrosine phosphorylation site, Y44 in KAT5. Other parvoviruses share a similar genome organization and coding potential and may adapt a similar strategy for efficient viral replication and transcription.

Lower respiratory tract infection (LRTI) is one of the major reasons for childhood mortality that threaten the health of the public. We aimed to investigate the epidemiological pathogens and their infection analysis among children with LRTI. Sputum specimens were collected for polymerase chain reaction detection and microbiological tests to identify the viral infection and bacterial infection. The serological specimens were separated from venous blood using for Mycoplasma pneumoniae and Chlamydia pneumoniae detection. The virus was confirmed in 86.2% of the children. Human rhinovirus (38.3%), respiratory syncytial virus (32.1%), and parainfluenza virus type 3 (27.2%) were the most frequently identified pathogens. Patients with viral and bacterial coinfection showed younger age ( p = 0.032), a higher proportion of wheezing rales ( p = 0.032), three depressions sign ( p = 0.028), and tachypnea ( p = 0.038), and more likely associated with severe pneumonia ( p = 0.035). Additionally, older children were more susceptible to viral‐atypical bacterial coinfection ( p = 0.032). Vomiting ( p = 0.011) and fever ( p = 0.003) were more likely to occur in children with viral‐atypical bacterial coinfection. Attention should be paid to the virus infection of LRTI, as viral‐bacterial coinfection and viral‐atypical bacterial co‐infection may have a detrimental impact on the gravity of LTRI.