Data_Sheet_1_Exploring the causal relationship between gut microbiota and multiple myeloma risk based on Mendelian randomization and biological annotation.PDF

IntroductionThe microbial genome-wide association studies (mbGWAS) have highlighted significant host-microbiome interactions based on microbiome heritability. However, establishing causal relationships between particular microbiota and multiple myeloma (MM) remains challenging due to limited sample sizes.MethodsGut microbiota data from a GWAS with 18,340 participants and MM summary statistics from 456,348 individuals. The inverse variance-weighted (IVW) method was used as the main bidirectional Mendelian randomization (MR) analysis. To assess the robustness of our results, we further performed supplementary analyses, including MR pleiotropy residual sum and outlier (MR-PRESSO) test, MR-Egger, Weighted median, Simple mode, and Weighted mode. Moreover, a backward MR analysis was conducted to investigate the potential for reverse causation. Finally, gene and gene-set-based analyses were then conducted to explore the common biological factors connecting gut microbiota and MM.ResultsWe discovered that 10 gut microbial taxa were causally related to MM risk. Among them, family Acidaminococcaceae, Bacteroidales family S24-7, family Porphyromonadaceae, genus Eubacterium ruminantium group, genus Parabacteroides, and genus Turicibacter were positively correlated with MM. Conversely, class Verrucomicrobia, family Verrucomicrobiaceae, genus Akkermansia, and order Verrucomicrobiales were negatively correlated with MM. The heterogeneity test revealed no Heterogeneity. MR-Egger and MR-PRESSO tests showed no significant horizontal pleiotropy. Importantly, leave-one-out analysis confirmed the robustness of MR results. In the backward MR analysis, no statistically significant associations were discovered between MM and 10 gut microbiota taxa. Lastly, we identified novel host-microbiome shared genes (AUTS2, CDK2, ERBB3, IKZF4, PMEL, SUOX, and RAB5B) that are associated with immunoregulation and prognosis in MM through biological annotation.DiscussionOverall, this study provides evidence supporting a potential causal relationship between gut microbiota and MM risk, while also revealing novel host-microbiome shared genes relevant to MM immunoregulation and clinical prognosis.</p

Table_1_Exploring the causal relationship between gut microbiota and multiple myeloma risk based on Mendelian randomization and biological annotation.XLSX

IntroductionThe microbial genome-wide association studies (mbGWAS) have highlighted significant host-microbiome interactions based on microbiome heritability. However, establishing causal relationships between particular microbiota and multiple myeloma (MM) remains challenging due to limited sample sizes.MethodsGut microbiota data from a GWAS with 18,340 participants and MM summary statistics from 456,348 individuals. The inverse variance-weighted (IVW) method was used as the main bidirectional Mendelian randomization (MR) analysis. To assess the robustness of our results, we further performed supplementary analyses, including MR pleiotropy residual sum and outlier (MR-PRESSO) test, MR-Egger, Weighted median, Simple mode, and Weighted mode. Moreover, a backward MR analysis was conducted to investigate the potential for reverse causation. Finally, gene and gene-set-based analyses were then conducted to explore the common biological factors connecting gut microbiota and MM.ResultsWe discovered that 10 gut microbial taxa were causally related to MM risk. Among them, family Acidaminococcaceae, Bacteroidales family S24-7, family Porphyromonadaceae, genus Eubacterium ruminantium group, genus Parabacteroides, and genus Turicibacter were positively correlated with MM. Conversely, class Verrucomicrobia, family Verrucomicrobiaceae, genus Akkermansia, and order Verrucomicrobiales were negatively correlated with MM. The heterogeneity test revealed no Heterogeneity. MR-Egger and MR-PRESSO tests showed no significant horizontal pleiotropy. Importantly, leave-one-out analysis confirmed the robustness of MR results. In the backward MR analysis, no statistically significant associations were discovered between MM and 10 gut microbiota taxa. Lastly, we identified novel host-microbiome shared genes (AUTS2, CDK2, ERBB3, IKZF4, PMEL, SUOX, and RAB5B) that are associated with immunoregulation and prognosis in MM through biological annotation.DiscussionOverall, this study provides evidence supporting a potential causal relationship between gut microbiota and MM risk, while also revealing novel host-microbiome shared genes relevant to MM immunoregulation and clinical prognosis.</p

KIT activation & up-regulation, concomitant parallel induction of ET3, KIT⁺Melan-A^–- progenitor cells, and melanocyte regeneration in proportion to sun-exposure.

<p>(<b><i>A</i></b>), IHC of KIT and ET3 on serial sections of human skin specimen obtained from a lower extremity-amputation. Sole represents active suppression of melanogenesis (<i>a</i> and <i>d</i>), dorsum of big toe represents intermediate sun-exposure (<i>b</i> and <i>e</i>), and lateral lower leg represents heavy sun-exposure (<i>c</i> and <i>f</i>). (<b><i>B</i></b>), IHC of KIT, Melan-A, and ET3 on serial sections of human skin punch biopsy specimens obtained from sun-protected axilla (<i>g</i>, <i>i</i>, <i>k</i>) and chronic heavy sun-exposed forearm (<i>h</i>, <i>j</i>, <i>l</i>) from the same individual. Lymphocytes serve as internal negative control for KIT, ET3 and Melan-A; mast cells serve as internal positive control for KIT. Together, these images demonstrate that human skin exhibits sun-exposure-dependent up-regulation of KIT (<i>a-c</i>) and concomitant parallel sun-exposure-induced increasing induction of ET3 (<i>d-f</i>). Chronic sun-exposure induces intense dendritic pattern of KIT expression as well as a large increase in the number of KIT-expressing-cells in the basal layer (<i>h</i>) consisting of KIT⁺Melan-A⁺ mature melanocytes (<i>j</i>) and KIT⁺Melan-A^–melanocyte progenitor cells as evidenced by the difference between (<i>h</i>) and (<i>j</i>).</p

Autophosphorylation, internalization, and nuclear localization of activated KIT with tyrosine phosphorylation at 568/570 (pY568/pY570KIT).

<p>(<b><i>A</i></b>), IHC of frozen sections of an aggressive GIST (<i>a-c</i>) and a normal human adult testis as external control (<i>d-f</i>) using pan-KIT antibody (<i>a</i> and <i>d</i>), pY568/pY570KIT antibody (b and <i>e</i>, red arrow indicates nuclear localization), and pY703KIT antibody (<i>c</i> and <i>f</i>) respectively. (<b><i>B</i></b>), <i>In situ</i> IHC to assess kinetics of SCF-induced nuclear translocation of pY568/pY570KIT using WM793 melanoma cells cultured in 4-well chamber tissue culture treated glass slides. Control (<i>g)</i> without SCF stimulation, after addition of SCF to culture media, the nuclear localization of pY568/pY570KIT increases progressively (<i>h-j</i>) in more than 90% of WM793 cells, reaches a plateau about 40–60 minutes (<i>i</i> and <i>j</i>), begins to decrease at 90 minutes (<i>k</i>), and is completely absent in nucleus with relocation back to the cytoplasm at 4 hours, some residual cytoplasmic staining remains visible (<i>l</i>).</p

Microarray analysis comparing a highly aggressive GIST with an indolent GIST: A selective list of target genes whose expression was up- or down-regulated by KIT signaling.

<p>Microarray analysis comparing a highly aggressive GIST with an indolent GIST: A selective list of target genes whose expression was up- or down-regulated by KIT signaling.</p

Immunohistochemical studies on human colon myenteric plexus demonstrate that 48 hours fasting results in activation of SCF-KIT signaling and concomitant parallel induction of endothelin-3.

<p>Human colon specimens post 48 hours fasting demonstrate intense KIT staining in ICCs within the myenteric plexus (<i>a</i>), and intense ET3 staining within the myenteric plexus (<i>b</i>). In sharp contrast, the surrounding longitudinal and circular smooth muscle cells (SM) show negative ET3 staining.</p