San Jose, Calif.-based Edison Pharmaceuticals, a biotech working on drugs to treat cellular-metabolism disorders, raised $4.25 million in a second funding round, VentureWire reports (subscription required). The investors were private individuals.

Edison is focused on diseases that affect mitochondria, organelles inside cells that, among other things, generate most of a cell's source of chemical energy. Inherited or acquired mitochondrial defects can disrupt electron flow within cells, leading to a buildup of "free radicals" that can damage other cellular functions. Many of these diseases are quite rare, although Edison believes that they share some common mechanisms with more widely known problems such as Parkinson's disease and diabetes.

The company said the funding will be used to advance two drug candidates -- one for inherited mitochrondrial respiratory chain disease, the other for Huntingdon's disease -- into human testing next year. CEO Guy Miller told VentureWire that Edison will also be announcing "two significant partnerships" within 40 days, one involving a specialty pharmaceutical company.