Min Qian

Purpose Genome-wide association studies have identified SMAD7 as a colorectal cancer (CRC) susceptibility gene. However, its underlying mechanism has not yet been characterized. This study screened functional SNPs (fSNPs) related to colorectal cancer through Reel-seq and obtained regulatory proteins on functional SNPs. Methods The candidate fSNPs on the SMAD7 locus were screened by Reel-seq method. Eight SNPs such as rs8085824 were identified as functional SNPs by luciferase reporter assay and EMSA, SDCP-MS and AIDP-WB revealed that HNRNPK can specifically bind to the rs8085824-C allele. The knockdown of HNRNPK by RNAi proved that HNRNPK could affect cell function by regulating SMAD7. Results Eight functional SNPs was found on the SMAD7 locus in linkage disequilibrium (LD) with R² > 0.8, i.e., rs12953717, rs7227023, rs34007497, rs58920878, rs8085824, rs4991143, rs4939826, and rs7227023. We also identified allele-imbalanced binding of HNRNPK to rs8085824, H1-3 to rs12953717, THOC6 to rs7227023, and DDX21 to rs58920878. Further functional analysis revealed that these proteins are the regulatory proteins that modulate the expression of SMAD7 in the human colorectal cancer cell line DLD1. In particular, we discovered that siRNA knockdown of HNRNPK inhibits cell proliferation and cell clonal formation by downregulating SMAD7, as the decreased cell proliferation and cell clonal formation in the siRNA HNRNPK knockdown cells was restored by SMAD7 overexpression. Conclusion Our findings reveal a mechanism which underlies the contribution of the fSNP rs8085824 on the SMD7 locus to CRC susceptibility.

Toxoplasmosis is a zoonotic parasitic disease caused by Toxoplasma gondii. Toxoplasma gondii infection of the lungs can lead to severe pneumonia. However, few studies have reported Toxoplasma pneumonia. Most reports were clinical cases due to the lack of a good disease model. Therefore, the molecular mechanisms, development, and pathological damage of Toxoplasma pneumonia remain unclear. A mouse model of Toxoplasma pneumonia was established by nasal infection with T. gondii. The model was evaluated using survival statistics, lung morphological observation, and lung pathology examination by hematoxylin and eosin (H&E) and Evans blue staining at 5 days post-infection (dpi). Total RNA was extracted from the lung tissues of C57BL/6 mice infected with T. gondii RH and TGME49 strains at 5 dpi. Total RNA was subjected to transcriptome analysis by RNA sequencing (RNA-seq) followed by quantitative real-time polymerase chain reaction (qRT–PCR) validation. Transcript enrichment analysis was performed using the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases to assess the biological relevance of differentially expressed transcripts (DETs). C57BL/6 mice infected with T. gondii via nasal delivery exhibited weight loss, ruffled fur, and respiratory crackles at 5 dpi. The clinical manifestations and lethality of RH strains were more evident than those of TGME49. H&E staining of lung tissue sections from mice infected with T. gondii at 5 dpi showed severe lymphocytic infiltration, pulmonary edema, and typical symptoms of pneumonia. We identified 3167 DETs and 1880 DETs in mice infected with the T. gondii RH and TGME49 strains, respectively, compared with the phosphate-buffered saline (PBS) control group at 5 dpi. GO and KEGG enrichment analyses of DETs showed that they were associated with the immune system and microbial infections. The innate immune, inflammatory signaling, cytokine-mediated signaling, and chemokine signaling pathways displayed high gene enrichment. In this study, we developed a new mouse model for Toxoplasma pneumonia. Transcriptome analysis helped to better understand the molecular mechanisms of the disease. These results provided DETs during acute T. gondii lung infection, which expanded our knowledge of host immune defenses and the pathogenesis of Toxoplasma pneumonia.

Glypican-1 (GPC1) is a cell surface proteoglycan that is upregulated in multiple types of human cancers including pancreatic cancer. Here, we investigated whether GPC1 could be a target of antibody-toxin fusion proteins (i.e., immunotoxins) for treating pancreatic cancer. We constructed a panel of GPC1-targeted immunotoxins derived from a functional domain of Pseudomonas exotoxin A. An albumin-binding domain was also introduced into the anti-GPC1 immunotoxin to improve serum half-life. Small-molecule screening was performed to identify irinotecan that shows synergistic efficacy with the immunotoxin. We showed that GPC1 was internalized upon antibody binding. Anti-GPC1 immunotoxins alone inhibited tumor growth in a pancreatic cancer xenograft model. The immunotoxin treatment reduced active β-catenin expression in tumor cells. Furthermore, immunotoxins containing an albumin-binding domain in combination with irinotecan caused pancreatic tumor regression. GPC1 expression was reduced by the immunotoxin treatment due to the degradation of the internalized GPC1 and its short cellular turnover rate. Our data indicate that the GPC1-targeted immunotoxin inhibits pancreatic tumor growth via degradation of internalized GPC1, downregulation of Wnt signaling, and inhibition of protein synthesis. The anti-GPC1 immunotoxin in combination with irinotecan thus provides a potential new treatment strategy for patients with pancreatic tumors.

SUMMARY: Objectives: We aimed to analyse the molecular backgrounds of the family in which an eight‐day‐old baby was confirmed to have hemolytic disease of the newborn (HDN) and phenotype observed for the baby did not conform to the expected phenotype.Background: The silentRHCEallele is rare in the Rh system.Methods: To determine the antibody specificity, her family members' blood samples were collected and tested using routine serological methods. The Rh C + c‐e + E‐ phenotype observed for the baby did not conform to the expected phenotype based on the maternal RhC‐c + E + e‐ phenotype. TheRHgenes of the family members were further analysed by sequencing.Results: The Rh phenotypes of the baby, her brother, her mother and father were CCDee, CcDEe, ccDEE and CCDee, respectively. IgG anti‐e was confirmed to cause the HDN in the case. A heterozygous silentRHCE * 03(c.1059G > A) mutation in exon 7 was found in the baby and her mother, which is a novel nonsense allele caused by a premature termination codon (Trp353stop).Conclusion: The silentRHCE * 03(c.1059G > A) variant was observed in a heterozygous state in mother and baby. We predict that, had this occurred in the homozygous state, it would give rise to the rare D‐‐ phenotype. To enhance the safety of transfusion, considerable attention should be paid to theRHCEgene in the Chinese population.

G protein–coupled receptor 54 (GPR54), the key receptor for the neuropeptide hormone kisspeptin, plays essential roles in regulating puberty development and cancer metastasis. However, its role in the antiviral innate immune response is unknown. We report that virus-induced type I interferon (IFN-I) production was significantly enhanced in Gpr54-deficient cells and mice and resulted in restricted viral replication. We found a marked increase of kisspeptin in mouse serum during viral infection, which, in turn, impaired IFN-I production and antiviral immunity through the GPR54/calcineurin axis. Mechanistically, kisspeptin/GPR54 signaling recruited calcineurin and increased its phosphatase activity to dephosphorylate and deactivate TANK [tumor necrosis factor receptor-associated factor (TRAF) family member-associated NF-κB activator]–binding kinase 1 (TBK1) in a Ca²⁺-dependent manner. Thus, our data reveal a kisspeptin/GPR54/calcineurin-mediated immune evasion pathway exploited by virus through the negative feedback loop of TBK1 signaling. These findings also provide insights into the function and cross-talk of kisspeptin, a known neuropeptide hormone, in antiviral innate immune response.

Summary: As the most important host defence against viral infection, interferon (IFN) stimulates hundreds of antiviral genes (ISGs) that together establish an ‘antiviral state’. However, the antiviral function of most ISGs in viral infection still need further exploration. Here, we demonstrated that the expression of G‐protein‐coupled receptor 146 (GPR146) is highly increased by both IFN‐β and IFN‐γ in a signal transducer and activator of transcription 1‐dependent signalling pathway. Most importantly, overexpression of GPR146 protects the host cells from vesicular stomatitis virus and Newcastle disease virus infection but not from infection by herpes simplex virus. In contrast, the virus‐induced IFN‐β production changed little in Gpr146‐knockout cells. Furthermore, the Gpr146‐deficient mice showed similar susceptibility to wild‐type mice with vesicular stomatitis virus infection. Interestingly, the expression of GPR146 in virus‐infected cells was strikingly reduced and can partially explain why the viral infection was little influenced in Gpr146‐knockout mice. Surprisingly, virus‐activated IFN regulatory factor 3 (IRF3) signalling not only induces the expression of IFN but also represses GPR146 expression through HES1 (hairy and enhancer of split‐1)‐mediated transcriptional activity to establish a dynamic equilibrium between pro‐viral and antiviral stages in host cells. Taken together, these data reveal the antiviral role of GPR146 in fighting viral infection although the GPR146‐mediated protection is eliminated by IRF3/HES1‐signalling, which suggests a potential therapeutic significance of both GPR146 and HES1 signalling in viral infection.

Accumulating evidence suggests that β-amyloid (Aβ)-induced neuroinflammation plays a prominent and early role in Alzheimer’s disease (AD). In this study, we demonstrated that Presenilin 2 (PS2) deficiency facilitates Aβ-induced neuroinflammation and injury by upregulating P2X7 expression both in vitro and in vivo. PS2 knockout mice demonstrated increased cognitive impairments and cerebral injury. PS2 deficiency increased the expression of P2X7 both in neurons and microglial cells. Furthermore, extracellular ATP also increased in both Aβ-treated and untreated PS2 knockout microglial cells. Notably, Aβ-induced classical proinflammatory cytokines such as IL-1β, IL-1α and TNF-α were increased in PS2 knockout microglial cells, suggesting a potential role for PS2 in the regulation of neuroinflammation. The expression of P2X7 clearly increased in PS2 knockdown BV2 cells. Consistent with in vivo data, Aβ-induced IL-1β production was also clearly enhanced in PS2 knockdown BV2 cells. Additionally, expression of the transcription factor Sp1 was increased in PS2 knockdown cells. When we treated PS2 knockdown cells with the specific Sp1 inhibitor MIT, we observed that enhanced P2X7 expression was significantly rescued. Taken together, these data suggests that PS2 plays a protective role during Aβ-induced neuroinflammation and injury through down-regulation of P2X7 expression.