The N-acetyl glucosamine catabolic pathway has been well established as a critically essential pathway for the survival and pathogenesis of several intracellular pathogens. The intracellular form of Leishmania donovani resides inside the parasitophorous vacuole of macrophages. Recent studies have shown that amino sugars, such as N-acetyl glucosamine, are released from the turnover of host macromolecules, such as glycosaminoglycans, glycoproteins, and proteoglycans, inside the parasitophorous vacuole. Three enzymes, hexokinase (Hxk), N-acetyl glucosamine-6-phosphate deacetylase (NAGD) and glucosamine-6-phosphate deaminase (GND), are sequentially involved in the catabolism of GlcNAc. The Leishmania donovani genome encodes all enzymes of the GlcNAc catabolic pathway. Here, we investigated the role of the GlcNAc catabolic pathway in the proliferation and survival of L. donovani by characterizing the NAGD gene of this pathway. Recombinant LdNAGD displayed deacetylation activity and was localized inside the glycosomes. LdNAGD gene deletion impaired GlcNAc catabolism and was indispensable for the viability of L. donovani in media containing GlcNAc as the sole carbon source. Furthermore, these Δnagd cells showed attenuated virulence in THP-1 cells and a significantly reduced proliferation rate compared to wild type (WT) cells inside THP-1 cells. Our data suggested that LdNAGD is important for the intracellular proliferation of L. donovani and may represent a potential drug target.

N-乙酰氨基葡萄糖分解代谢途径已被很好地确立为几种细胞内病原体存活和发病的至关重要的途径。多诺瓦利什曼原虫的细胞内形式存在于巨噬细胞的寄生液泡内。最近的研究表明氨基糖，如 N-乙酰氨基葡萄糖，是从寄主液泡内的宿主大分子（如糖胺聚糖、糖蛋白和蛋白聚糖）的周转中释放出来的。三种酶，己糖激酶 (Hxk)、N-乙酰氨基葡萄糖-6-磷酸脱乙酰酶 (NAGD) 和氨基葡萄糖-6-磷酸脱氨酶 (GND)，依次参与 GlcNAc 的分解代谢。在杜氏利什曼原虫基因组编码 GlcNAc 分解代谢途径的所有酶。在这里，我们通过表征GlcNAc 分解代谢途径的 NAGD 基因来研究 GlcNAc 分解代谢途径在L. donovani增殖和存活中的作用。重组Ld NAGD 显示出脱乙酰活性并定位在糖体内。LdNAGD基因缺失受损的GlcNAc分解代谢并且是的生存能力必不可少杜氏利什曼原虫在含有GlcNAc的作为唯一碳源的培养基。此外，与 THP-1 细胞内的野生型 (WT) 细胞相比，这些 Δ nagd细胞在 THP-1 细胞中显示出减弱的毒力和显着降低的增殖率。我们的数据表明LdNAGD对L. donovani的细胞内增殖很重要，可能代表一个潜在的药物靶点。