Summary of Research

 

Dr. Jun Li's research has two arms – basic science studies and clinical research. The basic science studies focus on a better understanding of myelin biology and its applications in inherited peripheral nerve diseases, identification of molecular targets, and therapeutic development.

Clinical presentation of patients with Charcot-Marie-Tooth (CMT) diseases typically includes distal muscle weakness, sensory loss, foot deformities, and absent deep tendon reflexes. CMT has been classified into several categories based on electrophysiological and pathological changes in the nerves and the array of genetic causes. Currently, there are over 100 specific genes that are linked with different subtypes of CMT. However, over 30% of diagnosed inherited neuropathies still have no known genetic cause.

For basic studies, we investigate how myelinating Schwann cells interact with axons and how various genetic mutations in inherited peripheral neuropathies alter the molecular signaling between the two types of cells. We hope that these investigations will lead to molecular targets for developing therapeutic interventions.

Currently, we are studying several genes and their related CMT disease using multiple in vitro and in vivo models in our lab. One of these genes is described below: PMP22 – Peripheral Myelin Protein 22 - An autosomal dominant trisomy of a 1.4Mb region on chromosome 17p12 containing the PMP22 gene results in Charcot-Marie-Tooth disease type-1A (CMT1A) which affects one out of 5000 people. CMT1A is the most common form of inherited neuropathy. A heterozygous deletion in the same region of chromosome 17p12 causes hereditary neuropathy with liability to pressure palsies (HNPP). Our studies utilize specimens from patients with CMT1A or HNPP, mouse models with Pmp22 gene manipulated, or culture Schwann cells/neurons to understand how the mutations damage myelin and axons. With respect to our clinical studies, Dr. Jun Li directs a CMT clinic that is specifically designated for the patients with inherited peripheral neuropathies. This multi-disciplinary clinic occurs weekly at Houston Methodist Hospital. We are interested in genotype/phenotype correlation, identification of novel genes causing CMT, and use of non-invasive quantitative MRI of peripheral nerve and human skin biopsy as biomarkers in the progression of peripheral nerve pathology. Our lab is a part of the NIH-funded Inherited Neuropathies Consortium.

For patients who are interested in visiting our clinic for clinical care, please call Rachel Davis at 713-441-9120 or email rgapplegate@houstonmethodist.org for an appointment.