Chengzu Long, PhD

Monogenic disorders affect millions of people worldwide. Although individually relatively rare, together these diseases affect approximately 1 in 100 individuals. Recent advances in human pluripotent stem cell biology, molecular genetics, and novel genome editing are revolutionizing our approach to study disease pathology and eventually will allow the development of a potential cure.

Our projects focus on advancing the novel genome editing technology to model and treat cardiac and neuromuscular diseases in human stem cells and animal models.

Dilated cardiomyopathy (DCM) is the most common cause of heart failure, which affects over 38 million patients worldwide. Gene mutations are major causes of idiopathic DCM, with a population prevalence of 1 in 250 to 400 individuals. However, for decades these studies were severely hampered by the inaccessibility of human cardiac tissue for molecular mechanistic studies, the lack of appropriate methods to verify the causal role of the identified gene mutations in DCM populations, and the absence of small and large animal models with humanized genetic modifications. Duchenne muscular dystrophy (DMD) is a fatal muscle disease affecting 1 in 3,500 boys. DCM and heart failure are common, incurable, and lethal consequences of DMD. Although several gene therapies have been tested, there is no curative treatment so far. CRISPR (clustered regularly interspaced short palindromic repeats)/Cas9-mediated genomic editing system holds great potential to cure human genetic diseases. Using CRISPR/Cas9-mediated genomic editing (termed myoediting), we successfully prevented muscular dystrophy in mdx mice, a well-established mouse model (Science 345, 1184-8). We advanced myoediting to postnatal muscle tissues by delivering gene editing components via a harmless adeno-associated virus. Skeletal and cardiac muscle showed progressive rescue of dystrophin protein (Science 351, 400-3). This paved the way for novel genome editing-based therapeutics in DMD. To address several challenges for clinical applications of gene editing in vivo, we performed myoediting on representative iPSC (induced pluripotent stem cells)-derived cardiomyocytes from multiple patients with point, deletion, or duplication mutations and efficiently restored dystrophin protein expression in cardiomyocytes. Rescued DMD cardiomyocytes show enhanced function.

Epilepsy is characterized by recurrent paroxysmal seizures caused by excessive, hypersynchronous firing of neurons in the cerebral cortex and is one of the most prevalent and debilitating neurological conditions. Advances in genomics and our understanding of the molecular control of control of brain synchronization have set the stage for an increasing number of epilepsy-associated genes and their associated pathophysiological pathways being identified. So far, dysfunctions of more than 100 genes responsible for the firing and wiring of the epileptic brain have been discovered. However, for certain very rare forms of epilepsy such as those caused by mutations in DHPS, SCN1A, and CDKL5, our understanding of their corresponding epileptic pathology and development of potential therapeutics remains largely unknown to the general scientific and medical community. To address this clear gap, our lab aims to use CRISPR-mediated genome editing to address these heritable mutations in a manner that is highly personalized to each specific disease, and to develop strategies specific to the genetic architecture of each specific mutation. Unlike other gene therapy methods which add an architecture of each specific mutation. Unlike other gene therapy methods which add a functional copy of a gene to a patient’s cells but retain the original dysfunctional copy of the gene, the CRISPR/Cas9 system can remove the defect in a personalized manner. We are developing strategies to permanently correct diverse epilepsy mutations in the genome of patient-specific stem cells and induced neuronal cells, and designate this approach neuroediting. These studies will also produce new insights into the molecular pathophysiology of epilepsy and drive the formulation of personalized in vitro and in vivo models for drug discovery.