Evolutionary characterization and pathogenicity of Getah virus from pigs in Guangdong Province of China.

Getah virus (GETV) is an emerging zoonotic virus that can infect humans and many mammals through mosquitoes. In this study, a novel pathogenic GETV strain, GDQY2022, was isolated from a pig farm in Guangdong Province, China. Sequence comparisons and phylogenetic analysis showed that GDQY2022 belongs to group III (GIII) and was most closely related to strain HeN202009-2, with 99.78% nucleotide sequence identity. Histopathological examination revealed significant pathological changes, such as widened alveolar septum in the lungs with mild congestion and hemorrhage. Differences in viral load between tissues were assessed by real-time RT-PCR, and significantly higher levels of GETV were found in abdominal lymph nodes and lungs of subclinically and clinically affected pigs (P < 0.01). This study provides valuable data for understanding the risk of GETV infection in the pig industry and a reliable basis for studying the pathogenic mechanisms and diagnostic surveillance of GETV.

Identification and genomic characterization of a novel porcine parvovirus in China.

Porcine parvoviruses (PPVs) are a group of small non-enveloped viruses with seven species (porcine parvovirus 1-7, PPV1-7) have been identified. In this study, a novel porcine parvovirus, provisionally named porcine parvovirus 8 (PPV8), was initially identified via high-throughput sequencing (HTS) in porcine reproductive and respiratory syndrome virus-positive samples collected from swine herds in Guangdong province, 2021. The nearly full-length genome of PPV8 strain GDJM2021 is 4,380 nucleotides in length with two overlapping open ORFs encoding NS1 and VP1 respectively. Sequence analysis indicated that PPV8 shared 16.23-44.18% sequence identity at the genomic levels to PPV1-7 with the relatively highest homology to PPV1. PPV8-GDJM2021 shared 31.86-32.68% aa sequence identity of NS1 protein with those of PPV1 and porcine bufavirus (PBuV), and formed an independent branch neighboring to those formed by members of the genus Protoparvovirus. Of the 211 clinical samples collected from 1990 to 2021, 37 samples (17.5%) distributed over 12 regions in China were positive for PPV8 with time spanning 24 years (1998-2021). To our knowledge, this is the first report on the genomic characterization of the novel PPV8 and its epidemiological situations in China.

Comprehensive Evaluation of RNA and DNA Viromic Methods Based on Species Richness and Abundance Analyses Using Marmot Rectal Samples.

Viral metagenomics is the most powerful tool to profile viromic composition for a given sample. Different viromic methods, including amplification-free ones, have been developed, but choosing them for different purposes requires comprehensive benchmarks. Here, we assessed the performance of four routinely used methods, i.e., multiple displacement amplification (MDA), direct metagenomic sequencing (MTG), sequence-independent single-primer amplification (SIA), and metatranscriptomic sequencing (MTT), using marmot rectal samples as the templates spiked with five known viruses of different genome types. The obtained clean data were differently contaminated by host and bacterial genomes, resulting in MDA having the most, with ~72.1%, but MTT had only ~7.5% data, useful for follow-up viromic analysis. MDA showed a broader spectrum with higher efficiency to profile the DNA virome, and MTT captured almost all RNA viruses with extraordinary sensitivity; hence, they are advisable in richness-based viromic studies. MTG was weak in capturing single-stranded DNA viruses, and SIA could detect both RNA and DNA viruses but with high randomness. Due to biases to certain types of viruses, the four methods caused different alterations to species abundance compared to the initial virus composition. SIA and MDA introduced greater stochastic errors to relative abundances of species, genus, and family taxa, whereas the two amplification-free methods were more tolerant toward such errors and thus are recommendable in abundance-based analyses. In addition, genus taxon is a compromising analytic level that ensures technically supported and biologically and/or ecologically meaningful viromic conclusions. IMPORTANCE Viral metagenomics can be roughly divided into species richness-based studies and species abundance-based analyses. Viromic methods with different principles have been developed, but rational selection of these techniques according to different purposes requires comprehensive understanding of their properties. By assessing the four most widely used methods using template samples, we found that multiple displacement amplification (MDA) and metatranscriptomic sequencing (MTT) are advisable for species richness-based viromic studies, as they show excellent efficiency to detect DNA and RNA viruses. Meanwhile, metagenomic sequencing (MTG) and MTT are more compatible with stochastic errors of methods introduced into relative abundance of viromic taxa and hence are rational choices in species abundance-based analyses. This study also highlights that MTG needs to tackle host genome contamination and ameliorate the capacity to detect single-stranded DNA viruses in the future, and the MTT method requires an improvement in bacterial rRNA depletion prior to library preparation.

Emergence of human-porcine reassortment G9P[19] porcine rotavirus A strain in Guangdong Province, China.

Group A rotaviruses of the family Reoviridae is one of the important intestinal pathogens causing diarrhea in piglets and humans. A human-porcine reassortment rotavirus, GDJM1, was identified from outbreak of diarrhea in suckling piglets and it associated with 60.00% (324/540) morbidity and 20.99% (68/324) mortality in Guangdong Province of China in 2022. Thus, to further characterize the evolutionary diversity of GDJM1, all gene segments were analyzed. The genome constellation was G9-P[19]-I5-R1-C1-M1-A8-N1-T1-E1-H1. Nucleotide sequence identity and phylogenetic analyses showed that the VP6, VP7, NSP4 and NSP5 genes of GDJM1 were the most closely related to the respective genes of porcine strains, with the highest homology ranging from 95.65-98.55% identity. The remaining seven genes (VP1-VP4, NSP1-NSP3) were the most closely related to human strains, with the highest homology ranging from 91.83-96.69% similarity. Therefore, it is likely that GDJM1 emerged as the result of genetic reassortment between porcine and human rotaviruses. To our knowledge, this is the first report that a human-porcine reassortment G9P[19] RVA strain has been identified in mainland China, which providing important insights into evolutionary characterization of G9P[19] RVA strain, and reveals that the strain has a potential risk of cross-species transmission.

Human umbilical cord mesenchymal stem cells implantation accelerates cutaneous wound healing in diabetic rats via the Wnt signaling pathway.

OBJECTIVE: Difficulty in wound healing is one common complication of diabetes mellitus. The study explored whether the therapeutic effect of human umbilical cord mesenchymal stem cells (hUCMSCs) on diabetic ulcer wound was enhanced by the activation of the Wnt signaling pathway. METHODS: Rat diabetic model was established by intraperitoneal injection of Streptozotocin (STZ). hUCMSCs were purified and seeded on the collagen-chitosan laser drilling acellular dermal matrix (CCLDADM) scaffold, which was subsequently implanted into the cutaneous wound of normal and diabetic rats, followed by daily injection of Wnt signaling pathway agonist (Wnt3a) or antagonist (sFRP3) at the edge of the scaffold. Wound healing was checked on days 7, 14, and 21, and the fibrous tissue deposition, capillaries, and epidermal regeneration at the wound were examined by hematoxylin-eosin staining. The hUCMSCs-CCLDADM scaffold was cultured in vitro and treated with Wnt3a or sFRP3, followed by evaluation of cell proliferation, cell proliferation rate, survival status, and altered protein levels in the Wnt signaling pathway using BrdU staining, CCK-8 assay, live/dead staining, and Western blotting, respectively. RESULTS: On days 7 and 14 postoperatively, the speed of wound healing was significantly lower in diabetic rats than that in normal control rats. This phenomenon was significantly improved by the activation of the Wnt signaling pathway that also elevated the fibrous protein deposition and the abundance of capillary in the granulation tissue. Conversely, blockade of Wnt signaling slowed the healing of skin wound in diabetic rats. The activation of Wnt signaling pathway promoted the proliferation and differentiation and decreased the apoptosis of hUCMSCs, thereby elevating the number of living hUCMSCs on the CCLDADM scaffold, while the suppression exerted a contrary effect. CONCLUSION: The activation of the Wnt signaling pathway promotes the healing of diabetic skin wound by the regulation of proliferation and differentiation of hUCMSCs on the CCLDADM scaffold.

Long-term systemic toxicity of shikonin derivatives in Wistar rats.

Abstract Context: Although the antitumor, immunomodulatory activities, and other effects of shikonin have been studied for decades, its systemic toxicity in vivo remains unclear. Objective: To estimate the long-term systemic toxicity of shikonin derivatives (ShD) in a rat model. Materials and methods: The roots of Arnebia euchroma (Royle) Johnst. (Boraginaceae) were extracted in ethanol, passed through a molecular sieve, and dried. A microemulsion solution in water was subsequently prepared. Adult Wistar rats were treated with ShD by gavage at concentrations of 200, 400, and 800 mg/kg per day for 90 days or 180 days. Hematological and biochemical examinations were performed, and the vital organs were subjected to pathological analyses. Results: We did not observe hematological or non-hematological toxicity of ShD at a dose as high as 800 mg/kg per day for 6 months. Discussion and conclusion: Our findings may offer some beneficial information for the practical application and research of Arnebia euchroma. We demonstrated in an animal model that ShD may be safe for usage.

[Biological significance of relationship between nuclear localization of Rac1 and progression of gastric carcinoma].

OBJECTIVE: To observe the subcellular localization of Rac1 and the expression of Tiam1 and Rac1 in gastric carcinoma, in order to reveal the relationship between the distribution of Rac1 and progression of gastric carcinoma. METHODS: Both carcinoma and adjacent normal tissue of 48 patients with gastric carcinoma were studied in this study. Tissue distribution and expression of Rac1 and Tiam1 were analyzed by immunohistochemistry and real-time polymerase chain reaction (PCR). RESULTS: Compared with that of adjacent non-cancerous gastric mucosa, the expression of Rac1 in cancer tissues was significantly increased. The positive rate of Rac1 expression was 18.8% (9/48 cases) in adjacent non-neoplastic gastric and 79.2% (38/48 cases) in cancer tissues. The positive staining was mainly located in the cell nuclei (31 samples). The real-time PCR results demonstrated that the expression levels of Tiam1 and Rac1 mRNA in cancerous tissues with nuclear localization of Rac1 were evidently increased. Furthermore, nuclear localization of Rac1 was associated with tumor stage and metastasis. CONCLUSIONS: The majority of gastric cancer tissues show nuclear dislocalization of Rac1 expression, which may be a sign of abnormal activation of Tiam1-Rac1 pathway. It may suggest enhanced invasion ability of the gastric carcinoma.