PPARG and congenital rubella syndrome: Combined with our previous finding that d-mannose can rescue the defects of Tph2 histone acetylation in CRS-exposure mice by directly entering the brain, we propose that d-mannose can also activate ACSS2–PPARγ–TPH2 axis via elevating brain SCFAs and reversing the dysbiosis of the gut microbiota in CRS mice.