Recombinant Derp5 allergen with αS1-casein signal peptide secreted in murine milk protects against dust mite allergen-induced airway inflammation

A hypomorphic mutation in the mouse Csn1s1 gene generated by CRISPR/Cas9 pronuclear microinjection

Caseins are major milk proteins that have an evolutionarily conserved role in nutrition. Sequence variations in the casein genes affect milk composition in livestock species. Regulatory elements of the casein genes could be used to direct the expression of desired transgenes into the milk of transgenic animals. Dozens of casein alleles have been identified for goats, cows, sheep, camels and horses, and these sequence variants are associated with altered gene expression and milk protein content. Most of the known mutations affecting casein genes’ expression are located in the promoter and 3’-untranslated regions. We performed pronuclear microinjections with Cas9 mRNA and sgRNA against the first coding exon of the mouse Csn1s1 gene to introduce random mutations in the α-casein (Csn1s1) signal peptide sequence at the beginning of the mouse gene. Sanger sequencing of the founder mice identified 40 mutations. As expected, mutations clustered around the sgRNA cut site (3 bp from PAM). Most of the mutations represented small deletions (1–10 bp), but we detected several larger deletions as well (100–300 bp). Functionally most mutations led to gene knockout due to a frameshift or a start codon loss. Some of the mutations represented in-frame indels in the first coding exon. Of these, we describe a novel hypomorphic Csn1s1 (Csn1s1c.4-5insTCC) allele. We measured Csn1s1 protein levels and confirmed that the mutation has a negative effect on milk composition, which shows a 50 % reduction in gene expression and a 40–80 % decrease in Csn1s1 protein amount, compared to the wild-type allele. We assumed that mutation affected transcript stability or splicing by an unknown mechanism. This mutation can potentially serve as a genetic marker for low Csn1s1 expression.

Oral immunotherapy with the ingestion of house dust mite extract in a murine model of allergic asthma

Background

Allergen-specific immunotherapy (ASIT) has the potential to modify allergic diseases, and it is also considered a potential therapy for allergic asthma. House dust mite (HDM) allergens, a common source of airborne allergen in human diseases, have been developed as an immunotherapy for patients with allergic asthma via the subcutaneous and sublingual routes. Oral immunotherapy with repeated allergen ingestion is emerging as another potential modality of ASIT. The aim of this study was to evaluate the therapeutic efficacy of the oral ingestion of HDM extracts in a murine model of allergic asthma.

Methods

BABL/c mice were sensitized twice by intraperitoneal injection of HDM extracts and Al(OH)₃ on day 1 and day 8. Then, the mice received challenge to induce airway inflammation by intratracheal instillation of HDM extracts on days 29–31. The treatment group received immunotherapy with oral HDM extracts ingestion before the challenge. All the mice were sacrificed on day 32 for bronchoalveolar inflammatory cytokines, mediastinal lymph node T cells, lung histology, and serum HDM-specific immunoglobulins analyses.

Results

Upon HDM sensitization and following challenge, a robust Th2 cell response and eosinophilic airway inflammation were observed in mice of the positive control group. The mice treated with HDM extracts ingestion had decreased eosinophilic airway inflammation, suppressed HDM-specific Th2 cell responses in the mediastinal lymph nodes, and attenuated serum HDM-specific IgE levels.

Conclusions

Oral immunotherapy with HDM extracts ingestion was demonstrated to have a partial therapeutic effect in the murine model of allergic asthma. This study may serve as the basis for the further development of oral immunotherapy with HDM extracts in allergic asthma.

Kefir peptides prevent high-fructose corn syrup-induced non-alcoholic fatty liver disease in a murine model by modulation of inflammation and the JAK2 signaling pathway

OBJECTIVE

In recent years, people have changed their eating habits, and high-fructose-containing bubble tea has become very popular. High-fructose intake has been suggested to be a key factor that induces non-alcoholic fatty liver disease (NAFLD). Kefir, a fermented milk product composed of microbial symbionts, has demonstrated numerous biological activities, including antibacterial, antioxidant and immunostimulating effects. The present study aims to evaluate the effects of kefir peptides on high-fructose-induced hepatic steatosis and the possible molecular mechanism.

RESULTS

An animal model of 30% high-fructose-induced NAFLD in C57BL/6J mice was established. The experiment is divided into the following six groups: (1) normal: H₂O drinking water; (2) mock: H₂O+30% fructose; (3) KL: low-dose kefir peptides (50 mg kg^-1)+30% fructose; (4) KM: medium-dose kefir peptides (100 mg kg^-1)+30% fructose; (5) KH: high-dose kefir peptides (150 mg kg^-1)+30% fructose; and (6) CFM: commercial fermented milk (100 mg kg^-1)+30% fructose. The results show that kefir peptides improve fatty liver syndrome by decreasing body weight, serum alanine aminotransferase, triglycerides, insulin and hepatic triglycerides, cholesterol, and free fatty acids as well as the inflammatory cytokines (TNF-α, IL-6 and IL-1β) that had been elevated in fructose-induced NAFLD mice. In addition, kefir peptides markedly increased phosphorylation of AMPK to downregulate its targeted enzymes, ACC (acetyl-CoA carboxylase) and SREBP-1c (sterol regulatory element-binding protein 1), and inhibited de novo lipogenesis. Furthermore, kefir peptides activated JAK2 to stimulate STAT3 phosphorylation, which can translocate to the nucleus, and upregulated several genes, including the CPT1 (carnitine palmitoyltransferase-1) involved in fatty acid oxidation.

CONCLUSION

Our data have demonstrated that kefir peptides can improve the symptoms of NAFLD, including body weight, energy intake, inflammatory reaction and the formation of fatty liver by activating JAK2 signal transduction through the JAK2/STAT3 and JAK2/AMPK pathways in the high-fructose-induced fatty liver animal model. Therefore, kefir peptides may have the potential for clinical application for the prevention or treatment of clinical metabolic syndrome.