Molecular characterization of MAP9 in the photoreceptor sensory cilia as a modifier in canine RPGRIP1-associated cone-rod dystrophy.

Photoreceptors possess a highly specialized primary cilium containing expanded ciliary membrane discs called the outer segment. The photoreceptor cilium is essential for the maintenance of the outer segment, and pathogenic variants in more than 50 cilia-related genes have been identified as causing non-syndromic inherited retinal diseases in patients. The retinitis pigmentosa GTPase regulator interacting protein 1 (RPGRIP1) is a structural protein localized to the photoreceptor cilium and biallelic RPGRIP1 variants have been associated with non-syndromic human inherited retinal diseases. In a canine cone-rod dystrophy model, a naturally occurring 44-bp exonic insertion in RPGRIP1 (RPGRIP1ins44/ins44) is the primary disease locus while an additional homozygous variant in MAP9 (microtubule associated protein 9) (MAP9aff/aff) acts as a modifier associated with early disease onset. MAP9 was originally identified as a microtubule-binding protein stabilizing microtubule structure during both mitosis and interphase in human cell lines. However, the roles of MAP9 in primary cilia, including photoreceptor neurosensory cilia, have not been well understood. Hence, we characterized the pathogenic phenotypes associated with homozygous MAP9 variant, and investigated the molecular function of MAP9 in primary cilia using the RPGRIP1-associated oligogenic canine cone-rod dystrophy model as well as cultured cells. Both functionally and structurally, the RPGRIP1ins44/ins44 MAP9aff/aff retina exhibited progressive cone photoreceptor degeneration starting earlier than the retina affected by RPGRIP1ins44/ins44 alone. Based on immunostaining of canine retinal sections and cultured cells, we found that MAP9 is prominently localized in the basal body of primary cilia and played an important role in maintaining the structure of ciliary microtubule axoneme. These findings suggest that the affected MAP9, together with mutant RPGRIP1, is deprived of critical roles in cilia organization and maintenance resulting in altered cilia structure and function giving rise to early onset and accelerated disease progression in the RPGRIP1ins44/ins44 MAP9aff/aff double homozygote cone-rod dystrophy canine model.

Extended functional rescue following AAV gene therapy in a canine model of LRIT3-congenital stationary night blindness.

Congenital stationary night blindness (CSNB) is a group of inherited retinal diseases in which either rod-to-ON-bipolar cell (ON-BC) signaling, or rod function is affected leading to impaired vision under low light conditions. One type of CSNB is associated with defects in genes (NYX, GRM6, TRPM1, GPR179, and LRIT3) involved in the mGluR6 signaling cascade at the ON-BC dendritic tips. We have previously characterized a canine model of LRIT3-CSNB and demonstrated short-term safety and efficacy of an ON-BC targeting AAV-LRIT3 (AAVK9#4-shGRM6-cLRIT3-WPRE) gene therapy. Herein, we demonstrate long-term functional recovery and molecular restoration following subretinal injection of the ON-BC targeting AAV-LRIT3 vector in all eight treated eyes for up to 32 months. Following subretinal administration of the therapeutic vector, expression of the LRIT3 transgene, as well as restoration of mGluR6 signaling cascade member TRPM1, were confirmed in the outer plexiform layer (OPL) of the treated area. However, further investigation of the transgene LRIT3 transcript expression by RNA in situ hybridization (RNA-ISH) revealed off-target expression in non-BCs including the photoreceptors, inner nuclear, and ganglion cell layers, despite the use of a mutant AAVK9#4 capsid and an improved mGluR6 promoter designed to specifically transduce and promote expression in ON-BCs. While the long-term therapeutic potential of AAVK9#4-shGRM6-cLRIT3-WPRE is promising, we highlight the necessity for further optimization of AAV-LRIT3 therapy in the canine CSNB model prior to its clinical application.

Medication adherence: is it a hidden drug-related problem in hidden elderly?

AIM: The present study aimed to identify the health needs of the hidden elderly in Hong Kong, and to investigate the impacts of pharmacist and nursing interventions on medication management and well-being in hidden elderly. METHODS: Participants were recruited by social workers if they were aged 65 years or older; did not have normal social life and network; did not have family support; and were not linked to the existing network of community support. Pharmacists identified drug-related problems. The health needs of participants were assessed by observations and interviews. Outcome measurements were scores of Morisky 8-item Medication Adherence Scale and EuroQoL (Quality of Life) 5-D Questionnaire. RESULTS: A total of 93 participants were recruited and 86 participants completed the study. The mean age was 81.46 ± 5.70 years, the mean number of chronic disease was 3.29 ± 1.45 and the mean number of chronic medications was 6.36 ± 2.96. The most commonly observed chronic diseases were hypertension, cardiac problems, diabetes, hyperlipidemia and arthritis. Drug non-adherence and storage problems were found in 61.63% and 69.77% of participants. The mean total EuroQoL score increased by 1.05 (P ≤ 0.001). The mean Morisky score decreased by 0.61, signifying improvement of medication adherence (P< 0.001). Female sex (P = 0.045), polypharmacy with more than nine concurrent medications (P = 0.013), arthritis (P = 0.006) and drug storage problems (P = 0.002) were identified as factors associated with poor medication adherence. CONCLUSIONS: The majority of hidden elderly suffered from multiple chronic diseases, and the prevalence of drug-related problems was high. Pharmacist and nursing interventions improved drug-related problems, drug compliance and quality of life in hidden elderly.