More than a decade after biotechs first began exploring the potential of protein degraders to treat cancer, the modality has started to steadily pick up steam in other disease areas. The latest to join this trend, Trimtech Therapeutics, pulled in a $31-million financing backed by Pfizer and Eli Lilly on Wednesday to develop brain-penetrant degraders for neurodegenerative diseases. At least two other firms have disclosed protein degrader projects in neuro, and several others have announced broad interest in immunology and inflammation (I&I). Booster Therapeutics, another early-stage startup, raised a $15-million seed round in October to target "toxic, misfolded proteins" to treat diseases such as Alzheimer's and Parkinson's. That same month, Biogen inked a deal with Neuromorph to develop molecular glue degraders for Alzheimer’s and other neurological conditions. Kymera Therapeutics announced last year it planned to pivot its degraders away from oncology and toward immunology, and Novartis and AbbVie each have secured I&I-focused molecular glue collaborations (see – Spotlight On: Novartis adds protein degrader to immunology pipeline and Vital Signs: Mapping protein degradation partnerships). Using a unique ubiquitinTrimtech's seed round was led by its founders, Cambridge Innovation Capital and SV Health Investors’ Dementia Discovery Fund (DDF), along with M Ventures and Pfizer Ventures. Additional backers include Lilly, MP Healthcare Venture Management Cambridge Enterprise Ventures and Start Codon.The funding will help the company develop small molecule degraders that recruit the E3 ubiquitin ligase TRIM21 to treat severe neurodegenerative and inflammatory disorders, such as Alzheimer’s and Huntington’s disease. The seed round should provide enough runway for Trimtech to generate in vivo proof-of-concept data for its lead programme in translational preclinical models.While many neurodegenerative diseases are characterised by protein aggregates, "traditional degrader approaches are not well-suited to degrading these toxic aggregates, preferring monomeric targets," CEO Nicola Thompson told FirstWord, adding that TRIM21 "is ideally suited to degrading these complexes because of its role in removing large viral particles from the cell as part of our natural viral defence mechanism."That's because TRIM21 is only "switched on" by multimeric targets like oligomers, aggregates or functional assemblies in a process called substrate-induced activation."In this way, TRIM21 is naturally selective for the toxic forms of the protein aggregate… while preserving healthy native versions of these proteins to maintain proper cell function," she added. Additionally, TRIM21's selectively means Trimtech doesn't need to design separate aggregate selective target binders, like those required by other E3 ubiquitin ligase-based degraders that preferentially target the monomeric versions of the proteins.Trimtech plans to develop two kinds of degraders: TRIMTACs, bispecific chimaeric molecules that recruit TRIM21 to a target protein, and TRIMGLUEs, which bring a target and TRIM21 together by exploiting cryptic mutual binding interactions.