Targeting the Proteostasis Network: New Therapeutic Approaches to Combat Aging

The loss of proteostasis, the cellular system responsible for maintaining a healthy and functional proteome, is one of the most consequential hallmarks of aging. As the proteostasis network declines with age, misfolded and aggregated proteins accumulate, contributing to cellular dysfunction and driving the pathology of neurodegenerative diseases, cardiovascular disease, and other age-related conditions. The therapeutic targeting of the proteostasis network represents one of the most promising frontiers in aging intervention research.

Understanding how to enhance protein quality control through pharmacological, genetic, and lifestyle approaches may provide strategies to slow or partially reverse the cellular deterioration that accompanies aging (Hipp et al., 2019; PMID: 30595587).

The Proteostasis Network: A Refresher

The proteostasis network consists of three integrated branches: protein synthesis and folding (guided by molecular chaperones), protein trafficking (moving proteins to their correct locations), and protein degradation (removing damaged proteins via the ubiquitin-proteasome system and autophagy).

With aging, each of these branches deteriorates. Chaperone expression and function decline, particularly under stress conditions. Proteasome activity decreases by 40-50% in some tissues. Autophagy efficiency drops, leading to accumulation of damaged organelles and protein aggregates. And the unfolded protein response (UPR), the stress signaling pathway that activates protective measures, becomes impaired.

Therapeutic Strategies

Chaperone Enhancement

Molecular chaperones, particularly heat shock proteins (HSPs), assist in protein folding and prevent aggregation. Several approaches to enhancing chaperone function are being investigated (Bose & Bhattacharyya, 2019; PMID: 31186102).

Heat Shock Response Activators: Small molecules that activate heat shock factor 1 (HSF1), the master transcription factor for chaperone gene expression, can upregulate chaperone production. Compounds like arimoclomol amplify the heat shock response without directly inducing stress. Clinical trials of arimoclomol in amyotrophic lateral sclerosis (ALS) have provided proof-of-concept for chaperone-enhancing therapeutics.

Chemical Chaperones: Small molecules such as 4-phenylbutyrate (4-PBA) and tauroursodeoxycholic acid (TUDCA) can stabilize protein structure and prevent aggregation without acting as true molecular chaperones. These compounds have shown benefits in models of diabetes, neurodegeneration, and liver disease.

HSP90 Modulators: HSP90 is a critical chaperone that maintains the stability and function of hundreds of client proteins. Low-dose HSP90 inhibitors can paradoxically trigger a compensatory increase in overall chaperone expression through HSF1 activation, potentially providing broad proteostasis enhancement.

Proteasome Activation

The proteasome, the cell’s primary protein degradation machinery, declines in activity with age. Strategies to restore or enhance proteasome function include the following.

Proteasome Activators: Compounds that enhance proteasome activity without causing nonspecific protein degradation are being developed. Betulinic acid, oleuropein (from olive leaf), and certain synthetic molecules have shown proteasome-activating properties in cell and animal models.

Preventing Proteasome Oxidation: The proteasome itself is vulnerable to oxidative damage, which reduces its catalytic activity. Antioxidant strategies that specifically protect proteasomal components may help maintain degradation capacity.

Immunoproteasome Modulation: The immunoproteasome, an alternative form that becomes more prevalent with age and inflammation, generates different peptide products than the constitutive proteasome. Modulating the balance between these forms may improve protein quality control in aging tissues.

Autophagy Enhancement

Autophagy, the bulk degradation pathway that removes protein aggregates and damaged organelles, is a major target for proteostasis-based aging interventions (Leidal et al., 2021; PMID: 34267498).

mTOR Inhibitors: Rapamycin and its analogs (rapalogs) are the most potent known autophagy inducers and consistently extend lifespan in animal models. Intermittent dosing protocols are being explored to reduce side effects while maintaining autophagy enhancement.

AMPK Activators: Metformin and other AMPK activators promote autophagy through mTOR-independent mechanisms. The TAME (Targeting Aging with Metformin) trial is evaluating whether metformin can delay age-related diseases in humans.

Spermidine and Natural Autophagy Inducers: Spermidine, found in wheat germ and certain other foods, induces autophagy through epigenetic mechanisms and has extended lifespan in multiple model organisms. It represents one of the most accessible autophagy-enhancing strategies.

TFEB Activation: Transcription factor EB (TFEB) is a master regulator of autophagy and lysosomal biogenesis. Small molecules that activate TFEB, such as curcumin analogs, may enhance both autophagy initiation and the degradative capacity of lysosomes.

UPR Modulation

The unfolded protein response (UPR), which detects the accumulation of misfolded proteins in the endoplasmic reticulum (ER), can be therapeutically modulated.

Mild UPR activation can upregulate chaperone production and enhance protein quality control. However, sustained, strong UPR activation triggers apoptosis. The goal is to find compounds that promote the adaptive, protective branches of the UPR without triggering the apoptotic branch.

Lifestyle Approaches to Proteostasis Support

Exercise

Physical exercise is one of the most potent natural activators of the proteostasis network. Exercise upregulates heat shock protein expression, enhances proteasome activity, activates autophagy through AMPK and mTOR modulation, and improves overall protein quality control in skeletal muscle, heart, and brain.

Caloric Restriction and Fasting

Caloric restriction and intermittent fasting enhance proteostasis through multiple mechanisms, including autophagy activation, reduced mTOR signaling, and upregulation of chaperone proteins. These dietary approaches may represent the most accessible strategy for supporting protein homeostasis.

Heat and Cold Therapy

Heat exposure (sauna use) activates the heat shock response, upregulating chaperones. Cold exposure activates cold shock proteins that may protect against protein misfolding. Both represent hormetic stressors that may strengthen the proteostasis network.

Challenges and Future Directions

The therapeutic targeting of proteostasis faces several challenges. The proteostasis network is highly interconnected, and modulating one component may have unintended effects on others. Different tissues may have different proteostasis requirements, complicating systemic interventions. The safety window between beneficial proteostasis enhancement and harmful over-activation is not well defined. And biomarkers for measuring proteostasis capacity in living humans are limited, making it difficult to assess intervention effectiveness.

Despite these challenges, the proteostasis network remains one of the most druggable hallmarks of aging, and continued research is likely to yield clinically useful interventions.

Frequently Asked Questions

Can I improve my proteostasis naturally? Yes. Regular exercise, intermittent fasting or caloric restriction, sauna use, adequate sleep, and a diet rich in polyphenols and other bioactive compounds may all support the proteostasis network. These lifestyle interventions activate multiple branches of protein quality control, including chaperone expression, autophagy, and proteasome function. Consistency over time is key for maintaining these benefits.

Which supplements may support proteostasis? Several supplements have shown proteostasis-relevant effects in laboratory and animal studies. Spermidine enhances autophagy. Curcumin may activate TFEB and support autophagy. Green tea EGCG has been shown to activate both autophagy and proteasome pathways. Oleuropein from olive leaf extract may enhance proteasome activity. However, the translation of these effects to meaningful clinical benefits in humans remains to be fully established.

Why is proteostasis loss linked to neurodegenerative diseases? Neurons are particularly vulnerable to proteostasis failure because they are post-mitotic (they do not divide and thus cannot dilute accumulated damage through cell division), they have very high metabolic rates generating substantial oxidative stress, they contain extremely long processes (axons) that require efficient protein trafficking, and many neurodegenerative diseases involve the accumulation of specific misfolded protein aggregates (amyloid-beta, tau, alpha-synuclein). These factors make the brain especially dependent on a functional proteostasis network.