Heterozygous CARD9 mutation favors the development of allergic bronchopulmonary aspergillosis

Background:Previous research demonstrated that a homozygous mutation of g.136372044G>A(S12N)in caspase recruitment domain family member 9(CARD9)is critical for producing Aspergillus fumigatus-induced(Af-induced)T helper 2(T_(H)2)-mediated responses in allergic bronchopulmonary aspergillosis(ABPA).However,it remains unclear whether the CARD9^(S12N)mutation,especially the heterozygous occurrence,predisposes the host to ABPA.Methods:A total of 61 ABPA patients and 264 controls(including 156 healthy controls and 108 asthma patients)were recruited for sequencing the CARD9 locus to clarify whether patients with this heterozygous single-nucleotide polymorphisms are predisposed to the development of ABPA.A series of in vivo and in vitro experiments,such as quantitative real-time polymerase chain reaction,flow cytometry,and RNA isolation and quantification,were used to illuminate the involved mechanism of the disease.Results:The presence of the p.S12N mutation was associated with a significant risk of ABPA in ABPA patients when compared with healthy controls and asthma patients,regardless of Aspergillus sensitivity.Relative to healthy controls without relevant allergies,the mutation of p.S12N was associated with a significant risk of ABPA(OR:2.69 and 4.17 for GA and AA genotypes,P=0.003 and 0.029,respectively).Compared with patients with asthma,ABPA patients had a significantly higher heterozygous mutation(GA genotype),indicating that p.S12N might be a significant ABPA-susceptibility locus(aspergillus sensitized asthma:OR:3.02,P=0.009;aspergillus unsensitized asthma:OR:2.94,P=0.005).The mutant allele was preferentially expressed in ABPA patients with heterozygous CARD9^(S12N),which contributes to its functional alterations to facilitate Af-induced T_(H)2-mediated ABPA development.In terms of mechanism,Card9 wild-type(Card9^(WT))expression levels decreased significantly due to Af-induced decay of its messenger RNA compared to the heterozygous Card9 S12N.In addition,ABPA patients with heterozygous CARD9^(S12N)had increased Af-induced interleukin-5 production.Conclusion:Our study provides the genetic evidence showing that the heterozygous mutation of CARD9^(S12N),followed by allele expression imbalance of CARD9^(S12N),facilitates the development of ABPA.

Low-protein diets supplemented with glutamic acid or aspartic acid ameliorate intestinal damage in weaned piglets challenged with hydrogen peroxide

Glutamic acid(Glu)and aspartic acid(Asp)are acidic amino acids with regulatory roles in nutrition,energy metabolism,and oxidative stress.This study aimed to evaluate the effects of low-protein diets supplemented with Glu and Asp on the intestinal barrier function and energy metabolism in weaned piglets challenged with hydrogen peroxide(H2O2).Forty piglets were randomly divided into 5 groups:NC,PC,PGA,PG,and PA(n=8 for each group).Pigs in the NC and PC groups were fed a low-protein diet,while pigs in the PGA,PG,or PA groups were fed the low-protein diet supplemented with 2.0%Glu+1.0%Asp,2.0%Glu,or 1.0%Asp,respectively.On day 8 and 11,pigs in the NC group were intraperitoneally injected with saline(1 mL/kg BW),while pigs in the other groups were intraperitoneally administered 10%H2O2(1 mL/kg BW).On day 14,all pigs were sacrificed to collect jejunum and ileum following the blood sample collection in the morning.Notably,low-protein diets supplemented with Glu or Asp ameliorated the intestinal oxidative stress response in H2O2-challenged piglets by decreasing intestinal expression of genes(P<0.05)(e.g.,manganese superoxide dismutase[MnSOD],glutathione peroxidase[Gpx]-1,and Gpx-4)encoding oxidative stress-associated proteins,reducing the serum concentration of diamine oxidase(P<0.05),and inhibiting apoptosis of the intestinal epithelium.Glu and Asp supple-mentation attenuated the upregulated expression of energy metabolism-associated genes(such as hexokinase and carnitine palmitoyltransferase-1)and the H2O2-induced activation of acetyl-coenzyme A carboxylase(ACC)in the jejunum and adenosine monophosphate-activated protein kinase-acetyl-ACC signaling in the ileum.Dietary Glu and Asp also ameliorated intestinal barrier damage as indicated by restored intestinal histology and morphology.In conclusion,low-protein diets supplemented with Glu and Asp protected against oxidative stress-induced intestinal dysfunction in piglets,suggesting that this approach could be used as a nutritional regulatory protectant against oxidative stress.