Isolation and characterization of a new population of nasal surface macrophages and their susceptibility to PRRSV-1 subtype 1 (LV) and subtype 3 (Lena).

Sialoadhesin (Sn) and CD163 have been recognized as two important mediators for porcine reproductive and respiratory syndrome virus (PRRSV) in host macrophages. Recently, it has been demonstrated that the highly virulent Lena strain has a wider macrophage tropism than the low virulent LV strain in the nasal mucosa. Not only CD163(+)Sn(+) macrophages are infected by Lena but also CD163(+)Sn(-) macrophages. This suggests that an alternative receptor exists for binding and internalization of PRRSV Lena in the CD163(+)Sn(-) macrophages. Further investigation to find the new entry receptor was hampered by the difficulty of isolating these macrophages from the nasal mucosa. In the present study, a new population of CD163(+)Sn(-) cells has been identified that is specifically localized in the nasal lamina propria and can be isolated by an intranasal digestion approach. Isolated nasal cells were characterized using specific cell markers and their susceptibility to two different PRRSV-1 strains (LV and Lena) was tested. Upon digestion, 3.2% (flow cytometry)-6.4% (confocal microscopy) of the nasal cells were identified as CD163(+) and all (99.7%) of these CD163(+) cells were Sn-. These CD163(+)Sn(-) cells, designated as "nasal surface macrophages", showed a 4.9 times higher susceptibility to the Lena strain than to the LV strain. Furthermore, the Lena-inoculated cell cultures showed an upregulation of CD163. These results showed that our new cell isolation system is ideal for the further functional and phenotypical analysis of the new population of nasal surface macrophages and further research on the molecular pathogenesis of PRRSV in the nose

Comparison of primary virus isolation in pulmonary alveolar macrophages and four different continuous cell lines for type 1 and type 2 porcine reproductive and respiratory syndrome virus

Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) has a highly restricted cellular tropism. In vivo, the virus primarily infects tissue-specific macrophages in the nose, lungs, tonsils, and pharyngeal lymphoid tissues. In vitro however, the MARC-145 cell line is one of the few PRRSV susceptible cell lines that are routinely used for in vitro propagation. Previously, several PRRSV non-permissive cell lines were shown to become susceptible to PRRSV infection upon expression of recombinant entry receptors (e.g., PK15Sn-CD163, PK15S10-CD163). In the present study, we examined the suitability of different cell lines as a possible replacement of primary pulmonary alveolar macrophages (PAM) cells for isolation and growth of PRRSV. The susceptibility of four different cell lines (PK15Sn-CD163, PK15S10-CD163, MARC-145, and MARC-145Sn) for the primary isolation of PRRSV from PCR positive sera (both PRRSV1 and PRRSV2) was compared with that of PAM. To find possible correlations between the cell tropism and the viral genotype, 54 field samples were sequenced, and amino acid residues potentially associated with the cell tropism were identified. Regarding the virus titers obtained with the five different cell types, PAM gave the highest mean virus titers followed by PK15Sn-CD163, PK15S10-CD163, MARC-145Sn, and MARC-145. The titers in PK15Sn-CD163 and PK15S10-CD163 cells were significantly correlated with virus titers in PAM for both PRRSV1 (p < 0.001) and PRRSV2 (p < 0.001) compared with MARC-145Sn (PRRSV1: p = 0.22 and PRRSV2: p = 0.03) and MARC-145 (PRRSV1: p = 0.04 and PRRSV2: p = 0.12). Further, a possible correlation between cell tropism and viral genotype was assessed using PRRSV whole genome sequences in a Genome-Wide-Association Study (GWAS). The structural protein residues GP2:187L and N:28R within PRRSV2 sequences were associated with their growth in MARC-145. The GP5:78I residue for PRRSV2 and the Nsp11:155F residue for PRRSV1 was linked to a higher replication on PAM. In conclusion, PK15Sn-CD163 and PK15S10-CD163 cells are phenotypically closely related to the in vivo target macrophages and are more suitable for virus isolation and titration than MARC-145/MARC-145Sn cells. The residues of PRRSV proteins that are potentially related with cell tropism will be further investigated in the future

GPR105 Ablation Prevents Inflammation and Improves Insulin Sensitivity in Mice with Diet-Induced Obesity

GPR105, a G-protein coupled receptor for UDP-glucose, is highly expressed in several human tissues and participates in the innate immune response. Since inflammation has been implicated as a key initial trigger for type 2 diabetes, we hypothesized that GPR105 (official gene name: P2RY14) might play a role in the initiation of inflammation and insulin resistance in obesity. To this end, we investigated glucose metabolism in GPR105 knockout (KO) and wild-type (WT) mice fed a high-fat diet (HFD). We also examined whether GPR105 regulates macrophage recruitment to liver or adipose tissues by in vivo monocyte tracking and in vitro chemotaxis experiments, followed by transplantation of bone marrow from either KO or WT donors to WT recipients. Our data show that genetic deletion of GPR105 confers protection against HFD-induced insulin resistance, with reduced macrophage infiltration and inflammation in liver, and increased insulin-stimulated Akt phosphorylation in liver, muscle and adipose tissue. By tracking monocytes from either KO or WT donors, we found that fewer KO monocytes were recruited to the liver of WT recipients. Furthermore, we observed that UDP-Glc enhanced the in vitro migration of bone marrow-derived macrophages from WT but not KO mice, and that plasma UDP-Glc levels were significantly higher in obese versus lean mice. Finally, we confirmed that insulin sensitivity improved in HFD mice with a myeloid cell-specific deletion of GPR105. These studies indicate that GPR105 ablation mitigates HFD-induced insulin resistance by inhibiting macrophage recruitment and tissue inflammation. Hence, GPR105 provides a novel link between innate immunity and metabolism

A Triple Amino Acid Substitution at Position 88/94/95 in Glycoprotein GP2a of Type 1 Porcine Reproductive and Respiratory Syndrome Virus (PRRSV1) Is Responsible for Adaptation to MARC-145 Cells

The Meat Animal Research Center-145 (MARC-145) cell line has been proven to be valuable for viral attenuation regarding vaccine development and production. Cell-adaptation is necessary for the efficient replication of porcine reproductive and respiratory syndrome virus (PRRSV) in these cells. Multiple sequence analysis revealed consistent amino acid substitutions in GP2a (V88F, M94I, F95L) of MARC-145 cell-adapted strains. To investigate the putative effect of these substitutions, mutations at either position 88, 94, 95, and their combinations were introduced into two PRRSV1 (13V091 and IVI-1173) infectious clones followed by the recovery of viable recombinants. When comparing the replication kinetics in MARC-145 cells, a strongly positive effect on the growth characteristics of the 13V091 strain (+2.1 log10) and the IVI-1173 strain (+1.7 log10) compared to wild-type (WT) virus was only observed upon triple amino acid substitution at positions 88 (V88F), 94 (M94I), and 95 (F95L) of GP2a, suggesting that the triple mutation is a determining factor in PRRSV1 adaptation to MARC-145 cells

The nasal frontier : decoding the acute stage of PRRSV and ASFV infec,on, resul,ng in new insights in porcine nasal macrophages

Porcine reproductive and respiratory syndrome (PRRSV) and African swine fever (ASFV) are two of the most economically important infectious viruses in pigs. PRRSV, a positive-strand RNA virus, causes reproductive failure in breeding pigs and respiratory illness across all age groups. ASFV, a double-stranded DNA virus, is the cause of a severe disease, characterized by high fever and hemorrhages with a mortality rate as high as 100%. Transmission of these viruses occurs mainly through direct contact with infected animals or inhaling viral particles containing droplets. Pigs are particularly susceptible to these transmission routes due to their innate behaviors such as exploring and socializing using their noses. The transmission is increased in pig farming settings where pigs are housed at high densities and in closed units

Duodenal perforation in a puppy with canine parvovirus infection

Copyright and/or publishing rights held by the Canadian Veterinary Medical Association.A 2-month-old puppy was brought to a veterinary hospital with diarrhea, vomiting, and anorexia. The test for canine parvovirus was positive, and she was hospitalized for supportive care. Her gastrointestinal symptoms initially improved; however, vomiting and lethargy developed again in the second week of hospitalization. Abdominal ultrasonography results were suspicious of a duodenal perforation. Cytology of the abdominal effusion confirmed septic peritonitis; therefore, emergency exploratory laparotomy was performed. The surgery was successful, and the puppy recovered fully. When symptoms recur or deteriorate in patients with parvoviral infection, surgically curable complications may be disregarded if supportive therapy is continued without additional investigative examinations. This report highlights the usefulness of abdominal ultrasound in conjunction with fluid cytology to identify subsequent complications when the clinical signs of parvovirus deteriorate. Key clinical message: This case report demonstrates duodenal perforation as a complication of parvoviral infection. Abdominal ultrasonography and peritoneal fluid cytology can be crucial for the early recognition of intestinal complications requiring immediate successful perioperative treatment. Perforation duodénale chez un chiot infecté par le parvovirus canin. Un chiot de 2 mois a été amené dans un hôpital vétérinaire avec de la diarrhée, des vomissements et de l’anorexie. Le test de dépistage du parvovirus canin était positif et l’animal a été hospitalisé pour des soins de soutien. Ses symptômes gastro-intestinaux se sont initialement améliorés; cependant, des vomissements et une léthargie se sont à nouveau développés au cours de la deuxième semaine d’hospitalisation. Les résultats de l’échographie abdominale étaient suspects d’une perforation duodénale. La cytologie de l’épanchement abdominal a confirmé une péritonite septique; par conséquent, une laparotomie exploratrice d’urgence a été réalisée. L’opération a été un succès et le chiot s’est complètement rétabli. Lorsque les symptômes réapparaissent ou s’aggravent chez les patients atteints d’une infection parvovirale, les complications soignables chirurgicalement peuvent être ignorées si le traitement de soutien est poursuivi sans examens d’investigation supplémentaires. Ce rapport souligne l’utilité de l’échographie abdominale en conjonction avec la cytologie du liquide péritonéal pour identifier les complications ultérieures lorsque les signes cliniques associés au parvovirus se détériorent.Message clinique clé :Ce rapport de cas démontre une perforation duodénale comme complication d’une infection parvovirale. L’échographie abdominale et la cytologie du liquide péritonéal peuvent être cruciales pour la détection précoce des complications intestinales nécessitant un traitement per-opératoire immédiat réussi.(Traduit par Dr Serge Messier).N

Development and Evaluation of a Web-Based Self-Management Program for Korean Adult Patients with Irritable Bowel Syndrome Based on the Information–Motivation–Behavioral Skills Model

This study aimed to develop and assess the effectiveness of a web-based nutrition education program for self-managing IBS symptoms using the IMB model. This study used single-arm, pre–post study design to test the effectiveness of the nutrition education program after its development. Participants were adults in their twenties and thirties in South Korea with IBS according to the ROME IV diagnostic criteria (n = 49). For statistical analysis, normality was verified using the Shapiro–Wilk test, and variables that met the assumption of normality were analyzed using the paired t-test, and variables that did not meet the assumption of normality were analyzed using the Wilcoxon signed-rank test. p p = 0.015). IBS patients (n = 35) with no prior experience in nutrition education or diet modification also demonstrated a statistically significant increase in self-efficacy (p = 0.044) and nutrition knowledge (p = 0.016). The web-based nutrition education program based on the IMB model developed in this study was found to be effective. These results will contribute to diversifying symptom prevention strategies for patients with IBS

Susceptibility of perivenous macrophages to PRRSV-1 subtype 1 LV and PRRSV-1 subtype 3 Lena using a new vein explant model

Vessel pathology such as increased permeability and blue discoloration is frequently observed with highly pathogenic PRRSV strains. However, data concerning the viral replication in the environment of blood vessels are absent. In the present study, ex vivo models with swine ear and hind leg vein explants were established to study the interaction of PRRSV-1 subtype 1 reference strain LV and highly pathogenic subtype 3 strain Lena with perivenous macrophages. The replication characteristics of these two strains were compared in vein explants by immunofluorescence analysis. The explants maintained a good viability during 48 hours of in vitro culture. We found that CD163-positive macrophages were mainly present around the veins and their number gradually decreased with increasing distance from the veins and longer incubation time. More CD163(+)Sn(-) cells than CD163(+)Sn(+) cells (6.6 times more) were observed in the vein explants. The Lena strain demonstrated a higher replication level than the LV strain, with approximately 1.4-fold more infected cells in the surrounding areas of the ear vein and 1.1-fold more infected cells in the leg vein explants at 48 hours post inoculation. In both LV and Lena inoculated vein explants, most infected cells were identified as CD163(+)Sn(+) (> 94%). In this study, an ex vivo vein model was successfully established, and our findings will contribute to a better understanding of the vein pathology during viral infections (e.g., PRRS, classical and African swine fever)

Selection and validation of reference genes for RT-qPCR normalization of porcine alveolar macrophages (PAMs) for PRRSV studies

Abstract Porcine alveolar macrophages (PAMs) are widely used for in vitro studies of porcine respiratory viruses. Gene expression in these cells is altered by viral infection and cellular immune response. Real-time reverse transcription polymerase chain reaction (RT-qPCR) is a powerful technique for analyzing these changes. In order to obtain reliable quantitative RT-qPCR data and come to sound conclusions, stable reference genes are needed for normalization of target gene expression. In the present study, we evaluated the expression stability of nine reference genes in PAMs during cultivation and upon porcine reproductive and respiratory syndrome virus (PRRSV) inoculation. Using geNorm and NormFinder algorithms, we identified PSAP and GAPDH as the most stable reference genes under all experimental conditions. The selected reference genes were used for the normalization of CD163 expression under different conditions. This study demonstrates that selection of appropriate reference genes is essential for normalization and validation of RT-qPCR data across all experimental conditions. This study provides a new set of stable reference genes for future studies with porcine respiratory viruses in PAMs