Schultheis Nicholas, Becker Robert, Berhanu Gelila, Kapral Alexander, Roseman Matthew, Shah Shalini, Connell Alyssa, Selleck Scott
Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA, United States.
Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada.
Front Genet. 2023 Jan 9;13:1012706. doi: 10.3389/fgene.2022.1012706. eCollection 2022.
Heparan sulfate modified proteins or proteoglycans (HSPGs) are an abundant class of cell surface and extracellular matrix molecules. They serve important co-receptor functions in the regulation of signaling as well as membrane trafficking. Many of these activities directly affect processes associated with neurodegeneration including uptake and export of Tau protein, disposition of Amyloid Precursor Protein-derived peptides, and regulation of autophagy. In this review we focus on the impact of HSPGs on autophagy, membrane trafficking, mitochondrial quality control and biogenesis, and lipid metabolism. Disruption of these processes are a hallmark of Alzheimer's disease (AD) and there is evidence that altering heparan sulfate structure and function could counter AD-associated pathological processes. Compromising presenilin function in several systems has provided instructive models for understanding the molecular and cellular underpinnings of AD. Disrupting presenilin function produces a constellation of cellular deficits including accumulation of lipid, disruption of autophagosome to lysosome traffic and reduction in mitochondrial size and number. Inhibition of heparan sulfate biosynthesis has opposing effects on all these cellular phenotypes, increasing mitochondrial size, stimulating autophagy flux to lysosomes, and reducing the level of intracellular lipid. These findings suggest a potential mechanism for countering pathology found in AD and related disorders by altering heparan sulfate structure and influencing cellular processes disrupted broadly in neurodegenerative disease. Vertebrate and invertebrate model systems, where the cellular machinery of autophagy and lipid metabolism are conserved, continue to provide important translational guideposts for designing interventions that address the root cause of neurodegenerative pathology.
硫酸乙酰肝素修饰的蛋白质或蛋白聚糖(HSPGs)是一类丰富的细胞表面和细胞外基质分子。它们在信号调节以及膜运输中发挥重要的共受体功能。这些活动中的许多直接影响与神经退行性变相关的过程,包括Tau蛋白的摄取和输出、淀粉样前体蛋白衍生肽的处置以及自噬的调节。在本综述中,我们关注HSPGs对自噬、膜运输、线粒体质量控制和生物发生以及脂质代谢的影响。这些过程的破坏是阿尔茨海默病(AD)的一个标志,并且有证据表明改变硫酸乙酰肝素的结构和功能可以对抗与AD相关的病理过程。在多个系统中破坏早老素功能为理解AD的分子和细胞基础提供了有启发性的模型。破坏早老素功能会产生一系列细胞缺陷,包括脂质积累、自噬体到溶酶体运输的破坏以及线粒体大小和数量的减少。抑制硫酸乙酰肝素生物合成对所有这些细胞表型具有相反的作用,增加线粒体大小、刺激自噬流到溶酶体并降低细胞内脂质水平。这些发现提示了一种通过改变硫酸乙酰肝素结构和影响在神经退行性疾病中广泛破坏的细胞过程来对抗AD和相关疾病中发现的病理的潜在机制。脊椎动物和无脊椎动物模型系统中,自噬和脂质代谢的细胞机制是保守的,它们继续为设计解决神经退行性病理根源的干预措施提供重要的转化指导。