Ioannou Pavlos, Odiatis Christoforos, Hadjisavva Rania, Antoniadou Kyriaki, Pieri Myrtani, Malatras Apostolos, Papagregoriou Gregory, Aristotelous Antrea, Skourides Paris, Samiotaki Martina, Horaček Matija, Ljubanović Danica Galešić, Stylianou Kostas, Deltas Constantinos
biobank.cy Center of Excellence in Biobanking and Biomedical Research, Molecular Medicine Research Center, University of Cyprus, Nicosia, Cyprus; Department of Biological Sciences, University of Cyprus, Nicosia, Cyprus.
biobank.cy Center of Excellence in Biobanking and Biomedical Research, Molecular Medicine Research Center, University of Cyprus, Nicosia, Cyprus.
Kidney Int. 2025 Jun 6. doi: 10.1016/j.kint.2025.05.016.
Alport Syndrome is a severe inherited glomerulopathy caused by pathogenic variants in genes encoding collagen-IV, the most abundant component of the glomerular basement membrane. Patients with Alport lack effective therapies beyond blockade of the renin-angiotensin-aldosterone system. Here, we test 4-phenylbutyrate (4-PBA) and tauroursodeoxycholic acid (TUDCA), two chemical chaperones, to rescue mouse models of a later-onset Alport Syndrome.
Knock-in mice bearing the Col4a3:p.Gly1332Glu pathogenic substitution in homozygosity and a compound heterozygous model bearing the same variant and the knockout allele were used. Mice received chaperones either for short or long-term periods. Also we examined the expression and secretion of mutant α3 chains in primary cultured mouse podocytes.
TUDCA-treated Alport mice did not differ from the placebo-treated group. However, mice treated with 4-PBA demonstrated considerable improvement in the morphology and structure of glomerular basement membranes compared with control placebo-treated mice. Electron microscopy showed a 54% reduction of lesions and significant decline of lesion severity in the basement membrane of treated Alport mice. Additionally, treatment with 4-PBA reduced interstitial fibrosis, global and segmental glomerulosclerosis, while proteinuria and hematuria remained at low levels in Alport mice. In-vivo findings and in-vitro inhibition of the proteasome in primary cultured podocytes indicate that mutant collagen is reduced within the glomeruli of mutant mice, likely due to proteasomal degradation of misfolded collagen. Importantly, treatment of mice and cultured podocytes with 4-PBA improved secretion and incorporation of collagen IV into extracellular matrix probably by enhancing trimer folding.
Our results suggest a therapeutic potential for 4-PBA in combating kidney dysfunction in Alport syndrome.
奥尔波特综合征是一种严重的遗传性肾小球病，由编码IV型胶原（肾小球基底膜最丰富的成分）的基因中的致病变异引起。除了阻断肾素-血管紧张素-醛固酮系统外，奥尔波特综合征患者缺乏有效的治疗方法。在此，我们测试了两种化学伴侣4-苯丁酸盐（4-PBA）和牛磺熊去氧胆酸（TUDCA），以挽救迟发性奥尔波特综合征的小鼠模型。
使用纯合携带Col4a3:p.Gly1332Glu致病性替代的敲入小鼠以及携带相同变体和敲除等位基因的复合杂合模型。小鼠接受短期或长期的伴侣治疗。我们还检测了原代培养的小鼠足细胞中突变α3链的表达和分泌。
TUDCA治疗的奥尔波特小鼠与安慰剂治疗组没有差异。然而，与对照安慰剂治疗的小鼠相比，用4-PBA治疗的小鼠肾小球基底膜的形态和结构有显著改善。电子显微镜显示，治疗的奥尔波特小鼠基底膜病变减少了54%，病变严重程度显著下降。此外，4-PBA治疗减少了间质纤维化、全球性和节段性肾小球硬化，而奥尔波特小鼠的蛋白尿和血尿仍维持在低水平。体内研究结果以及原代培养足细胞中蛋白酶体的体外抑制表明，突变小鼠肾小球内的突变胶原蛋白减少，可能是由于错误折叠的胶原蛋白被蛋白酶体降解。重要的是，用4-PBA治疗小鼠和培养的足细胞可能通过增强三聚体折叠改善了IV型胶原的分泌和向细胞外基质的整合。
我们的结果表明4-PBA在对抗奥尔波特综合征肾功能障碍方面具有治疗潜力。
