Linjing Li

• University of Massachusetts Chan Medical School

X-linked retinitis pigmentosa 2 (XLRP2) patients and Rp2null mice exhibit severe cone photoreceptor degeneration. However, due to the paucity of cones in mammalian model systems, it is not clear how cones respond to the loss of RP2. Here we have used the Nrl-/- mice, which develop a rodless and short wavelength (S) opsin-containing cone-only retina...

Representative pathways that are altered in the Rp2-DKO mice.

Differentially expressed genes in the Rp2-DKO mice.

Mutations in the cilia‐centrosomal protein CEP290 are frequently observed in autosomal recessive childhood blindness disorder Leber congenital amaurosis (LCA). No treatment or cure currently exists for this disorder. The Cep290rd16 (retinal degeneration 16) mouse (a mouse model of LCA) carries a mutation in the Cep290 gene. This mutation leads to s...

Mutations in the cilia-centrosomal protein CEP290 are most frequently observed in autosomal recessive childhood blindness disorder Leber congenital amaurosis (LCA). No treatment or cure currently exists for this disorder. The Cep290rd16 (retinal degeneration 16) (a mouse model of LCA) carries a mutation in the Cep290 gene, which leads to shorter ci...

Comment on: Identification and Correction of Mechanisms Underlying Inherited Blindness in Human iPSC-Derived Optic Cups. [Cell Stem Cell. 2016]

Ciliary trafficking defects underlie the pathogenesis of severe human ciliopathies, including Joubert Syndrome (JBTS), Bardet-Biedl Syndrome, and some forms of retinitis pigmentosa (RP). Mutations in the ciliary protein RPGR (retinitis pigmentosa GTPase regulator) are common causes of RP-associated photoreceptor degeneration worldwide. While previo...

Ciliary trafficking defects underlie the pathogenesis of severe human ciliopathies, including Joubert Syndrome (JBTS), Bardet-Biedl Syndrome, and some forms of retinitis pigmentosa (RP). Mutations in the ciliary protein RPGR (retinitis pigmentosa GTPase regulator) are common causes of RP-associated photoreceptor degeneration worldwide. While previo...

Ciliary dysfunction is an underlying cause of severe human disorders (collectively called ciliopathies), such as retinitis pigmentosa (RP), Joubert Syndrome (JBTS), and Bardet-Biedl Syndrome. Ciliary proteins form distinct functional networks for localization to cilia as well as regulation of ciliary function. However, not much is known about the m...

Mutants of RPGR (retinitis pigmentosa GTPase regulator) protein are the most common cause of X-linked RP, a severe blindness disorder. RPGR mutations result in clinically variable disease with early to late onset phenotypic presentation. Molecular mechanisms underlying such heterogeneity are unclear. Here we show that phenotypic expression of Rpgr-...

Mutations in RPGR (retinitis pigmentosa GTPase regulator) are the most common cause of X-linked RP, a severe blindness disorder. RPGR mutations result in clinically variable disease with early-to late-onset phenotypic presentation. Molecular mechanisms underlying such heterogeneity are unclear. Here we show that phenotypic expression of Rpgr-loss i...

Mutants of RPGR (retinitis pigmentosa GTPase regulator) protein are the most common cause of X-linked RP, a severe blindness disorder. RPGR mutations result in clinically variable disease with early to late onset phenotypic presentation. Molecular mechanisms underlying such heterogeneity are unclear. Here we show that phenotypic expression of Rpgr-...

It is unclear how genes, such as RPGR (retinitis pigmentosa guanine triphosphatase regulator) that are expressed in both rods and cones, cause variable disease pathogenesis. Using transcriptomic analysis, we show that loss of RPGR in a rod-dominant mouse retina (Rpgr ko) results in predominant alterations in genes involved in actin cytoskeletal dyn...

It is unclear how genes, such as RPGR (retinitis pigmentosa guanine triphosphatase regulator) that are expressed in both rods and cones, cause variable disease pathogenesis. Using transcriptomic analysis, we show that loss of RPGR in a rod-dominant mouse retina (Rpgrko) results in predominant alterations in genes involved in actin cytoskeletal dyna...

Retinal neurodegenerative diseases are especially attractive targets for gene replacement therapy, which appears to be clinically effective for several monogenic diseases. X-linked forms of retinitis pigmentosa (XLRP) are relatively severe blinding disorders, resulting from progressive photoreceptor dysfunction primarily caused by mutations in RPGR...

Degeneration of photoreceptors (rods and cones) results in blindness. As we rely almost entirely on our daytime vision mediated by the cones, it is the loss of these photoreceptors that results in legal blindness and poor quality of life. Cone dysfunction is usually observed due to two mechanisms: non cell-autonomous due to the secondary effect of...

Cilia regulate several developmental and homeostatic pathways that are critical to survival. Sensory cilia of photoreceptors regulate phototransduction cascade for visual processing. Mutations in the ciliary protein RPGR (retinitis pigmentosa GTPase regulator) are a prominent cause of severe blindness disorders due to degeneration of mature photore...

Retina is a neurosensory tissue lining the back of the eye and is responsible for light detection and relaying the signal to the visual cortex in the brain. Mammalian retina consists of six major types of neurons (including photoreceptors; rods and cones) and one type of glial cells arranged in distinct layers. Photoreceptors are the most abundant...

Purpose: In humans, over 80% of X- linked retinitis pigementosa (XLRP) is caused by mutations in RPGR. RPGR associated disease is clinically heterogeneous, indicating involvement of genes that can influence the associated phenotype. RPGR is known to interact with selected ciliary proteins including CEP290, RPGRIP1, NPHP1, NPHP4 and NPHP5. The purpo...

Purpose: Mutations in the RP2 gene are associated with 10% to 15% of X-linked retinitis pigmentosa (XLRP), a debilitating disorder characterized by the degeneration of retinal rod and cone photoreceptors. The molecular mechanism of pathogenesis of photoreceptor degeneration in XLRP-RP2 has not been elucidated, and no treatment is currently availab...

Gaucher disease (GD), caused by a defect of acid β-glucosidase (β-Glu), is one of the most common sphingolipidoses. Recently, ambroxol, an FDA-approved drug used to treat airway mucus hypersecretion and hyaline membrane disease in newborns, was identified as a chemical chaperone for GD. In the present study, we investigated the chaperone activity a...

Competitive inhibitors of either α-galactosidase (α-Gal) or β-galactosidase (β-Gal) with high affinity and selectivity have been accessed by exploiting aglycone interactions with conformationally locked sp(2)-iminosugars. Selected compounds were profiled as potent pharmacological chaperones for mutant lysosomal α- and β-Gal associated with Fabry di...

β-Galactosidase deficiency is a group of lysosomal lipid storage disorders with an autosomal recessive trait. It causes two clinically different diseases, G(M1) -gangliosidosis and Morquio B disease. It is caused by heterogeneous mutations in the GLB1 gene coding for the lysosomal acid β-galactosidase. We have previously reported the chaperone effe...

Gaucher disease (GD) is the most prevalent lysosomal-storage disorder, it is caused by mutations of acid β-glucosidase (β-glucocerebrosidase; β-Glu). Recently, we found that bicyclic nojirimycin (NJ) derivatives of the sp(2)-iminosugar type, including the 6-thio-N'-octyl-(5N,6S)-octyliminomethylidene derivative (6S-NOI-NJ), behaved as very selectiv...

Gaucher's disease (GD), mainly caused by a defect of acid beta-glucosidase (beta-Glu), is the most common form of sphingolipidosis. We have previously shown that the carbohydrate mimic and inhibitor of beta-Glu, N-octyl-beta-valienamine (NOV), could increase the protein level and enzyme activity of various mutant beta-Glus in cultured GD fibroblast...