The molecular basis of immune-based platelet disorders

Conjoint analysis of methylation, transcriptomic, and proteomic profiles in pemphigus vulgaris

BACKGROUND

The underlying pathogenesis of pemphigus vulgaris, an autoimmune skin disorder, remains incompletely understood. An integrative analysis comprising DNA methylation, mRNA expression, and proteomic data in patients with pemphigus vulgaris was conducted to identify potential pathogenic contributors and explore the molecular mechanisms involved in its pathogenesis.

RESULTS

The analysis revealed differentially methylated regions (DMRs) in the promoter, exon, intron, and downstream regions in the peripheral blood DNA of patients with pemphigus vulgaris. Associations between methylation levels and both transcriptomic and proteomic profiles revealed that differentially expressed genes between patients with pemphigus vulgaris and healthy controls were primarily linked to biological functions such as platelet activation and coagulation, cellular adhesion, and immunoglobulin binding. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis highlighted notable pathway abnormalities, including those related to platelet activation, focal adhesions, tight junctions, and infectious inflammatory responses. Notably, genes such as FGA (fibrinogen alpha chain), VWF (von Willebrand factor), and ACTG1 (actin gamma 1) were dysregulated, with a prominent role in platelet activation.

CONCLUSION

The dysregulation of genes such as FGA, VWF, and ACTG1 suggests that alterations in their transcription and expression may contribute to the pathogenesis of pemphigus vulgaris.

Iron and platelets: A subtle, under-recognized relationship

The role of iron in the formation and functioning of erythrocytes, and to a lesser degree of white blood cells, is well established, but the relationship between iron and platelets is less documented. Physiologically, iron plays an important role in hematopoiesis, including thrombopoiesis; iron levels direct, together with genetic factors, the lineage commitment of megakaryocytic/erythroid progenitors toward either megakaryocyte or erythroid progenitors. Megakaryocytic iron contributes to cellular machinery, especially energy production in platelet mitochondria. Thrombocytosis, possibly favoring vascular thrombosis, is a classical feature observed with abnormally low total body iron stores (mainly due to blood losses or decreased duodenal iron intake), but thrombocytopenia can also occur in severe iron deficiency anemia. Iron sequestration, as seen in inflammatory conditions, can be associated with early thrombocytopenia due to platelet consumption and followed by reactive replenishment of the platelet pool with possibility of thrombocytosis. Iron overload of genetic origin (hemochromatosis), despite expected mitochondrial damage related to ferroptosis, has not been reported to cause thrombocytopenia (except in case of high degree of hepatic fibrosis), and iron-related alteration of platelet function is still a matter of debate. In acquired iron overload (of transfusional and/or dyserythropoiesis origin), quantitative or qualitative platelet changes are difficult to attribute to iron alone due to the interference of the underlying hematological conditions; likewise, hematological improvement, including increased blood platelet counts, observed under iron oral chelation is likely to reflect mechanisms other than the sole beneficial impact of iron depletion.