Scientist / Research Associate, In Vitro & In Vivo Muscle Pharmacology

We are a stealth-stage company developing musculoskeletal therapeutics. We evaluate candidates across multiple modalities (peptides, small molecules, antibodies and other biologics, and gene-delivery constructs) and advance the ones that produce real functional benefit. You will own the in vitro and in vivo assays that decide which molecules work. This role is built around functional readouts (such as in vivo force, grip, and performance). You will set up assays largely from scratch and work directly with the founding team, so initiative and rigor matter as much as technique. What you'll do In vitro / cell-based assays Culture and differentiate myoblasts and myotubes (e.g., C2C12 and primary muscle cells); run hypertrophy and atrophy assays (myotube diameter, fusion index, protein synthesis and degradation). Build and run target-engagement and potency assays (signaling and reporter readouts, receptor binding, dose-response / EC50-IC50 characterization) across candidate modalities. Develop new assays from the literature and troubleshoot them to a reproducible, quantitative readout. Plan and execute efficacy studies end to end: dosing by multiple routes (IP, SC, IV, oral gavage), body-weight and clinical monitoring, with blinding and randomization. Run muscle challenge and recovery models (disuse and immobilization, injury and regeneration, aging, and related performance models). Measure the endpoints that matter: body composition (EchoMRI/DEXA) and, above all, functional outcomes: in vivo muscle force, grip strength, and treadmill/running performance. Perform terminal procedures, tissue collection, and perfusions; prepare muscle (and bone where relevant) for downstream analysis. Analysis, readouts, and operations Quantify tissue and molecular endpoints: histology and fiber cross-sectional-area morphometry, qPCR, Western blot, ELISA, and flow cytometry. Analyze and present data with appropriate statistics; keep rigorous electronic lab-notebook records and write study reports. Write and maintain IACUC protocols, manage breeding colonies and study logistics, and help stand up the vivarium workflow and SOPs. Work closely with the founding team to prioritize experiments and feed results back into candidate selection. What we're looking for (required) BS or MS in biology, physiology, pharmacology, biomedical science, or related field with 2+ years of hands‑on research experience, (or a PhD). We will scope the title and level (Research Associate through Staff Scientist) to your experience. Hands‑on experience running in vitro muscle‑cell assays: myoblast/myotube culture and differentiation, with hypertrophy and/or atrophy readouts. Hands‑on experience running in vivo muscle‑function assays in rodents: for example grip strength, in vivo or in situ muscle force, treadmill, or rotarod, including dosing and terminal procedures. Strong mammalian cell‑culture skills and a track record of quantitative, reproducible assays. Experience developing or optimizing an assay (not just running an established protocol), with the rigor to make the readout trustworthy: proper controls, blinding, randomization, and statistics. Current (or ready‑to‑obtain) animal‑handling training and comfort working under IACUC protocols. Meticulous record‑keeping, clear data presentation, and the self‑direction to run experiments with limited supervision in an early‑stage setting. Nice‑to‑haves Experience with skeletal muscle physiology and regeneration / satellite‑cell biology. Advanced in vivo functional phenotyping: in situ or in vivo plantarflexion/tetanic force, gait analysis, or ex vivo muscle mechanics. Surgical and challenge models: muscle injury (e.g., cardiotoxin or BaCl2), hindlimb suspension or immobilization, denervation, and bone models. Body‑composition methods in rodents (EchoMRI or DEXA). Experience with one or more therapeutic modalities: antibodies and other biologics, peptides, small molecules, or gene‑delivery / AAV constructs. Molecular and imaging readouts: qPCR, Western blot, ELISA, flow cytometry, immunohistochemistry, and quantitative histomorphometry. Data‑analysis fluency (GraphPad Prism, R, or Python) and electronic lab‑notebook / LIMS experience. Prior biotech or startup experience, and comfort helping build a lab and its SOPs from the ground up. Logistics Location: San Diego, CA. On-site (bench and vivarium work). Level: Research Associate to Scientist, scoped to experience. Reports to: Chief Technology Officer. Employment: Begins as contractor, opportunity for transition to full‑time. Compensation: $65,000 to $130,000 base, by level and experience, plus equity and bonus scaled to level and experience. Work authorization: Must be a U.S. citizen or permanent resident; we do not provide visa sponsorship. We are an equal‑opportunity employer. We consider all qualified applicants without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, disability, protected‑veteran status, or any other legally protected characteristic. #J-18808-Ljbffr