3.4 CUR reshapes the intestinal microflora composition of mice
Next, we further investigated the effect of CUR on the intestinal microbiota of mice. We examined the V3 and V4 regions within the 16sRNA of all mouse gut microbiota, and the rarefaction curves showed extremely high coverage in every sample (Figure. 3A). From the principal coordinate analysis (PCoA) results, we found a significant separation of the microflora distribution between groups CON, IMQ and CUR (Figure. 3B). After analyzing the flora diversity among the CON, IMQ and CUR groups, Simpson and Shannon index showed that the CON and CUR groups were significantly higher than the IMQ group (Figure. 3C-D). Moreover, the analysis of the microflora diversity results showed that it mainly included 10 classes: Bacilli , Clostridia ,Bacteroidia , Desulfovibrionia , Deferribacteria ,Campylobacteria , Saccharimonadia , Coriobacteriia ,Gammaproteobacteria , Alphaproteobacteria (Figure. 4A).
For further exploring these data, we performed high dimensional analysis by line discriminant analysis effect size (LEfSe) that determined significant differences in the main flora between CON, IMQ and CUR groups. The dominant flora was Lactobacillus at the genus level IMQ group, which we speculated is due to reduced diversity of microflora. The CUR group showed the dominant flora wereMucispirillumunclassified_desulfovibrionaceae at the genus level, while Deferribacters , Desulfovibrionia at the class level. The CON group revealed that the predominant flora wasRuminococcaceae at the family level (Supplementary Figure. 1A-B).
Subsequently, we performed Kruskal-Wallis test to detect the microflora differences between the three groups. Compared with CON and CUR groups, the relative abundance of Bacilli at the class level was marked increased in IMQ group, while the result of Desulfovibrionia was contrary (Figure. 4B-C). Moreover, compared with IMQ group, the relative abundances of clostridia, Deferribacteres at the class level were significantly promoted in the CUR group, while the result ofSaccharimonadia was opposite (Figure. 4B-C). Ultimately, at the genus level, the abundance of Alistipes , Mucispirillum ,Rikenella in CON and CUR groups was markedly higher than in the IMQ group (Figure. 5A-D).
3.5 Changed intestinal microflora by CUR was associated with psoriasis-related factors
To further understand the role of altered gut microbiota by CUR and its connections with psoriasis, we treated psoriasis-related inflammation indicators as a variable by spearman correlation analysis at the genus level based on OTU abundance, presented with a heatmap. As shown in Figure.6A, Ligilactobacillus and Anaeroplasma (inhibited in CUR mice) were positively correlated with multiple psoriasis-related factors, such as IL-6, IL-17A, IL-22, Il-23, while Rikenella, Alistipes, and Mucispirillum (promoted in CUR mice) were negatively correlated with them. These results indicated that the gut flora changes induced by CUR are associated with the inflammatory factors in psoriasis.