The Molecular Architecture of Neurodegeneration: An Integrative Overview of Convergent Mechanisms

Neurodegenerative diseases such as Alzheimer's, Parkinson's, amyotrophic lateral sclerosis, and Huntington's disease represent a major challenge in neuroscience due to their complex, multifactorial nature and the absence of curative treatments. These disorders share common molecular mechanisms, including oxidative stress, mitochondrial dysfunction, proteostasis collapse, calcium dyshomeostasis, chronic neuroinflammation, and the prion-like propagation of misfolded proteins. Together, these processes trigger a cascade of cellular damage that culminates in synaptic dysfunction and programmed neuronal death. This review integrates current evidence on the sequential stages of neurodegeneration, emphasizing the convergence of oxidative, inflammatory, and proteotoxic pathways that drive neuronal vulnerability. Moreover, it explores emerging therapeutic strategies aimed at restoring cellular homeostasis, such as Nrf2 activation, modulation of the unfolded protein response (UPR), enhancement of autophagy, immunotherapy against pathological proteins, and gene therapy approaches. The dynamic interplay among mitochondria, endoplasmic reticulum, and glial cells is highlighted as a central element in disease progression. Understanding these interconnected mechanisms provides a foundation for developing multi-targeted interventions capable of halting or delaying neuronal loss and improving clinical outcomes in neurodegenerative disorders. This work provides an integrative and introductory overview of the convergent mechanisms underlying neurodegeneration rather than an exhaustive mechanistic analysis.