Ceramide (Cer) is a structural backbone of sphingolipids and is composed of a long-chain base and a fatty acid. Existence of a variety of Cer species, which differ in chain-length, hydroxylation status, and/or double bond number of either of their hydrophobic chains, has been reported. Ceramide is produced by Cer synthases. Mammals have six Cer synthases (CERS1–6), each of which exhibits characteristic substrate specificity toward acyl-CoAs with different chain-lengths. Knockout mice for each Cer synthase show corresponding, isozyme-specific phenotypes, revealing the functional differences of Cers with different chain-lengths. Cer diversity is especially prominent in epidermis. Changes in Cer levels, composition, and chain-lengths are associated with atopic dermatitis. Acylceramide (acyl-Cer) specifically exists in epidermis and plays an essential role in skin permeability barrier formation. Accordingly, defects in acyl-Cer synthesis cause the cutaneous disorder ichthyosis with accompanying severe skin barrier defects. Although the molecular mechanism by which acyl-Cer is generated was long unclear, most genes involved in its synthesis have been identified recently. In Cer degradation pathways, the long-chain base moiety of Cer is converted to acyl-CoA, which is then incorporated mainly into glycerophospholipids. This pathway generates the lipid mediator sphingosine 1-phosphate. This review will focus on recent advances in our understanding of the synthesis and degradation pathways, physiological functions, and pathology of Cers/acyl-Cers.

神经酰胺（Cer）是鞘脂的结构骨架，由长链碱基和脂肪酸组成。据报道，存在多种Cer物种，它们的链长，羟基化状态和/或它们的疏水链中任何一个的双键数均不同。神经酰胺是由Cer合酶产生的。哺乳动物有六个Cer合成酶（CERS1-6），每个都对不同链长的酰基辅酶A表现出特征性的底物特异性。每种Cer合酶的基因敲除小鼠表现出相应的同工酶特异性表型，揭示了具有不同链长的Cer的功能差异。Cer多样性在表皮中尤为突出。Cer水平，组成和链长的变化与特应性皮炎有关。酰基神经酰胺（酰基Cer）特别存在于表皮中，并在皮肤渗透性屏障形成中起重要作用。因此，酰基-Cer合成中的缺陷引起皮肤疾病鱼鳞病，并伴有严重的皮肤屏障缺陷。尽管长久以来尚不清楚产生酰基Cer的分子机制，但最近已鉴定出参与其合成的大多数基因。在Cer降解途径中，Cer的长链碱基部分转化为酰基辅酶A，然后其主要掺入甘油磷脂中。该途径产生脂质介体鞘氨醇1-磷酸。这篇综述将集中在我们对Cers /酰基Cers的合成和降解途径，生理功能和病理学的理解方面的最新进展。酰基-Cer合成中的缺陷会导致皮肤疾病鱼鳞病，并伴有严重的皮肤屏障缺陷。尽管长久以来尚不清楚产生酰基Cer的分子机制，但最近已鉴定出参与其合成的大多数基因。在Cer降解途径中，Cer的长链碱基部分转化为酰基辅酶A，然后其主要掺入甘油磷脂中。该途径产生脂质介体鞘氨醇1-磷酸。这篇综述将集中在我们对Cers /酰基Cers的合成和降解途径，生理功能和病理学的理解方面的最新进展。酰基-Cer合成中的缺陷会导致皮肤疾病鱼鳞病，并伴有严重的皮肤屏障缺陷。尽管长久以来尚不清楚产生酰基Cer的分子机制，但最近已鉴定出参与其合成的大多数基因。在Cer降解途径中，Cer的长链碱基部分转化为酰基辅酶A，然后其主要掺入甘油磷脂中。该途径产生脂质介体鞘氨醇1-磷酸。这篇综述将集中在我们对Cers /酰基Cers的合成和降解途径，生理功能和病理学的理解方面的最新进展。最近已经确定了参与其合成的大多数基因。在Cer降解途径中，Cer的长链碱基部分转化为酰基辅酶A，然后其主要掺入甘油磷脂中。该途径产生脂质介体鞘氨醇1-磷酸。这篇综述将集中在我们对Cers /酰基Cers的合成和降解途径，生理功能和病理学的理解方面的最新进展。最近已经确定了参与其合成的大多数基因。在Cer降解途径中，Cer的长链碱基部分转化为酰基辅酶A，然后其主要掺入甘油磷脂中。该途径产生脂质介体鞘氨醇1-磷酸。这篇综述将集中在我们对Cers /酰基Cers的合成和降解途径，生理功能和病理学的理解方面的最新进展。