Molecular mechanisms of neurodegenerative disease (NDD)

Degenerative nerve diseases affect body's balance, movement, speech, breathing and heart function. Classification of neurodegenerative disorders can be done on the basis of their molecular cause, like abnormal protein aggregation, involved cell death or loss of function of involved cell. Parkinson's disease (PD) is associated with aggregation of α-synuclein, while Alzheimer disease (AD) is associated with tau, amyloid-β42 protein aggregation. TDP-43 aggregation was found in Amyloidosis. Besides, Argyrophilic grain disease (AGD); Amyotrophic lateral sclerosis (ALS); Astrocyte plaque (AP); ALS and Parkinsonism-Dementia Complex (APDC); Aging-related tau astrogliopathy (ARTAG); Ballooned neuron (BN); Cerebral age-related TDP-43 with sclerosis (CARTS); Corticobasal degeneration (CBD); Chronic traumatic encephalopathy (CTE); Dementia with Lewy bodies (DLB); Dystrophic neuritis (DN); Facial onset sensory and motor neuronopathy (FOSMN); Glial cytoplasmic inclusions (GCI); globular glial tauopathy (GGT); Guadeloupean Parkinsonism (GP); idiopathic REM sleep behavior disorder (iRBD); Limbic-predominant age-related TDP-43 encephalopathy (LATE); Lewy bodies (LB); Lewy body diseases (LBD); Lewy neuritis (LN); muscle cells (MC); multiple system atrophy (MSA); multisystem proteinopathy (MSP); Neuronal cytoplasmic inclusions (NCI); neurofibrillary tangles (NFT); neuronal intranuclear inclusions (NII); neuropil threads (NPT); Nodding Syndrome (NS); oligodendroglial coiled bodies (OCB); oligodendroglial Pick's body-like inclusions (OPiBLI); pure autonomic failure (PAF); primary age-related tauopathy (PART); Pick's bodies (PiB); Pick's disease (PiD); Primary lateral sclerosis (PLS); Progressive muscular atrophy (PMA); progressive supranuclear palsy (PSP); pretangles (PT); tufted astrocyte (TA), are several neurodegenerative diseases name according to their involved protein factor(s).

The cause may be genetic, may also be sporadic. Alcoholism, pesticides, a tumor, or a stroke are sometimes noticed in the disease background. Sometimes the cause remains totally unknown. Neurodegeneration, till date, cannot be cured. Only some palliative treatments may relieve some of the symptoms but temporarily. Further, some types of NDD could also be fatal.

Our focus, in this review, is mainly on AD and PD since they vastly affect millions of people in the world, and occurs when nerve cells lose functional ability and/or die over time. AD and PD, the likelihood of developing the issues rise dramatically with age. Unfortunately, there is no cure at present for them except some palliative measure to give some comfort to the victims. Improvement of our understanding about the cause(s) of neurodegenerative diseases may help to design the new approaches for treatment and prevention of the ailments. In recent days, high-throughput technologies like RNA sequencing, network biology, and Omics data provide insights of all neurodegenerative disease.