Protein-First, but Not Protein-Only: Rethinking Neurodegenerative Diseases Through Transgenic Mouse Models
Abstract
1. Introduction

2. A Protein-Centered View of Major Neurodegenerative Diseases
Why a Protein-Centered Framework Remains Useful
3. Transgenic Mouse Models as Mechanistic Tools
4. Strengths of Transgenic Mouse Models
5. Limitations of Current Mouse Models
6. From Single Models to Model Portfolios
7. Integrating Mouse Models with Human-Based Systems
8. Conclusions
Funding
Data Availability Statement
Conflicts of Interest
Abbreviations
| 3R tau | tau isoforms containing three microtubule-binding repeats |
| 3xTg-AD | triple-transgenic Alzheimer’s disease model |
| 4R tau | tau isoforms containing four microtubule-binding repeats |
| 5xFAD | mouse model carrying five familial Alzheimer’s disease mutations |
| Aβ | amyloid-β |
| αSyn | α-synuclein |
| AD | Alzheimer’s disease |
| ALS | amyotrophic lateral sclerosis |
| ALS-FTD | amyotrophic lateral sclerosis-frontotemporal dementia spectrum |
| APOE | apolipoprotein E |
| APP | amyloid precursor protein |
| ATXN1 | ataxin 1 |
| BAC | bacterial artificial chromosome |
| BACHD | bacterial artificial chromosome Huntington’s disease model |
| C9ORF72 | chromosome 9 open reading frame 72 |
| CAG | cytosine-adenine-guanine trinucleotide repeat |
| CBD | corticobasal degeneration |
| CNP | 2′,3′-cyclic nucleotide 3′-phosphodiesterase |
| DLB | dementia with Lewy bodies |
| DPRs | dipeptide repeat proteins |
| FTD | frontotemporal dementia |
| FTD-tau | frontotemporal dementia with tau pathology |
| FTD-TDP | frontotemporal dementia with TDP-43 proteinopathy |
| FUS | fused in sarcoma |
| GBA | glucocerebrosidase |
| GRN | progranulin gene |
| HD | Huntington’s disease |
| HTT | huntingtin |
| iPSC | induced pluripotent stem cell |
| LRRK2 | leucine-rich repeat kinase 2 |
| MAPT | microtubule-associated protein tau |
| MBP | myelin basic protein |
| MSA | multiple system atrophy |
| NMJ | neuromuscular junction |
| PD | Parkinson’s disease |
| PINK1 | PTEN-induced kinase 1 |
| PLP | proteolipid protein |
| PolyQ | polyglutamine |
| PrP | prion protein |
| PRNP | prion protein gene |
| PSEN1 | presenilin 1 |
| PSEN2 | presenilin 2 |
| PSP | progressive supranuclear palsy |
| RNA | ribonucleic acid |
| SCA | spinocerebellar ataxia |
| SMA | spinal muscular atrophy |
| SMN | survival motor neuron |
| SMN1 | survival motor neuron 1 |
| SMN2 | survival motor neuron 2 |
| SNCA | α-synuclein gene |
| SOD1 | superoxide dismutase 1 |
| TDP-43 | TAR DNA-binding protein 43 |
| TREM2 | triggering receptor expressed on myeloid cells 2 |
| YAC | yeast artificial chromosome |
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| Protein | Disease Context | Associated Disease | Model Implication | References |
|---|---|---|---|---|
| α-synuclein | Neuronal inclusions | Parkinson’s disease; DLB | Use neuronal α-synuclein models | [7,18,19] |
| Oligodendroglial inclusions | Multiple system atrophy | Use oligodendrocyte-directed α-synuclein models | [9,10,20] | |
| Tau | Mixed 3R and 4R tau with amyloid-β | Alzheimer’s disease | Use amyloid, tau, or combined AD models | [6,21] |
| Predominantly 4R tau | PSP; CBD | Use 4R tau or P301S/P301L tau models | [11,22] | |
| MAPT mutation | FTD-tau | Use mutation-driven tauopathy models | [22,23] | |
| TDP-43 | Motor neuron pathology | ALS | Use TDP-43 ALS models | [12,24,25] |
| Frontotemporal cortical pathology | FTD-TDP | Use cortical and behavior-focused models | [12,25] | |
| C9ORF72 | Repeat RNA, DPRs, TDP-43 pathology | ALS-FTD spectrum | Use C9ORF72 repeat models | [13,14,26] |
| Disease | Major Protein or Pathway | Representative Mouse Models | Main Use | Key Limitation | References |
|---|---|---|---|---|---|
| Alzheimer’s disease | amyloid-β, APP, PSEN1/PSEN2, tau | 5xFAD; APP/PS1; 3xTg-AD; AppNL-F; AppNL-G-F | Amyloid pathology; amyloid-tau interaction; neuroinflammation | Familial mutation bias; overexpression artifacts in some models | [21,29,30,31] |
| Parkinson’s disease/DLB | α-synuclein; LRRK2 | A53T α-synuclein; Thy1-α-synuclein; LRRK2-G2019S | Synucleinopathy; motor phenotypes; dopaminergic vulnerability | Incomplete Lewy body and nigral degeneration phenotypes | [18,19,32] |
| Multiple system atrophy | Oligodendroglial α-synuclein | PLP-α-synuclein; MBP-α-synuclein; CNP-α-synuclein | Glial cytoplasmic inclusions; neuron-glia interaction | Forced glial α-synuclein expression | [9,10,20] |
| Amyotrophic lateral sclerosis | SOD1; TDP-43; FUS; C9ORF72-associated DPRs | SOD1-G93A; TDP-43 A315T; rNLS8; C9ORF72 BAC; FUS-R521C | Motor neuron degeneration; NMJ loss; RNA toxicity | Model-specific phenotypes; SOD1 represents a subset | [24,25,26,33,34] |
| Frontotemporal dementia | Tau; TDP-43; FUS; GRN; C9ORF72 | rTg4510; PS19; Grn-deficient mice; C9ORF72 BAC | Cortical degeneration; behavioral phenotypes; tau/TDP-43 biology | Highly heterogeneous disease mechanisms | [22,23,26,35] |
| PSP/CBD | Predominantly 4R tau | PS19 (P301S tau); rTg4510 (P301L tau) | Tau aggregation; motor dysfunction | Limited modeling of sporadic glial tauopathy | [11,22,23] |
| Huntington’s disease | Mutant huntingtin | R6/2; YAC128; BACHD; zQ175 | PolyQ toxicity; striatal dysfunction; HTT-lowering studies | R6/2 is rapid and fragment-based; knock-ins are slower | [36,37,38,39] |
| Prion diseases | Misfolded PrP/PRNP | Prnp knockout; Tga20; humanized PRNP mice | Infectivity; strain biology; species barrier | Biosafety and strain specificity | [40,41,42] |
| Spinocerebellar ataxias | PolyQ-expanded ataxins | ATXN1[82Q]; SCA3-YAC; SCA7 models | Purkinje cell dysfunction; cerebellar degeneration | Subtype-specific mechanisms | [43,44,45] |
| Spinal muscular atrophy | SMN deficiency | SMN2-rescue mice; SMNΔ7; Taiwanese SMA model | SMN dosage; motor unit pathology; therapy testing | Neonatal severity; developmental component | [16,17,46] |
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Zeng, C.-W. Protein-First, but Not Protein-Only: Rethinking Neurodegenerative Diseases Through Transgenic Mouse Models. Neurol. Int. 2026, 18, 139. https://doi.org/10.3390/neurolint18070139
Zeng C-W. Protein-First, but Not Protein-Only: Rethinking Neurodegenerative Diseases Through Transgenic Mouse Models. Neurology International. 2026; 18(7):139. https://doi.org/10.3390/neurolint18070139
Chicago/Turabian StyleZeng, Chih-Wei. 2026. "Protein-First, but Not Protein-Only: Rethinking Neurodegenerative Diseases Through Transgenic Mouse Models" Neurology International 18, no. 7: 139. https://doi.org/10.3390/neurolint18070139
APA StyleZeng, C.-W. (2026). Protein-First, but Not Protein-Only: Rethinking Neurodegenerative Diseases Through Transgenic Mouse Models. Neurology International, 18(7), 139. https://doi.org/10.3390/neurolint18070139

