Macular crystalline inclusions in Sjögren-Larsson syndrome are dynamic structures that undergo remodeling

Unraveling the CLCC1 interactome: Impact of the Asp25Glu variant and its interaction with SigmaR1 at the Mitochondrial-Associated ER Membrane (MAM)

The endoplasmic reticulum (ER) plays an indispensable role in cellular processes, including maintenance of calcium homeostasis, and protein folding, synthesized and processing. Disruptions in these processes leading to ER stress and the accumulation of misfolded proteins can instigate the unfolded protein response (UPR), culminating in either restoration of balanced proteostasis or apoptosis. A key player in this intricate balance is CLCC1, an ER-resident chloride channel, whose essential role extends to retinal development, regulation of ER stress, and UPR. The importance of CLCC1 is further underscored by its interaction with proteins localized to mitochondria-associated endoplasmic reticulum membranes (MAMs), where it participates in UPR induction by MAM proteins. In previous research, we identified a p.(Asp25Glu) pathogenic CLCC1 variant associated with retinitis pigmentosa (RP) (CLCC1 hg38 NC_000001.11; NM_001048210.3, c.75C > A; UniprotKB Q96S66). In attempt to decipher the impact of this variant function, we leveraged liquid chromatography-mass spectrometry (LC-MS) to identify likely CLCC1-interacting proteins. We discovered that the CLCC1 interactome is substantially composed of proteins that localize to ER compartments and that the Asp25Glu variant results in noticeable loss and gain of specific protein interactors. Intriguingly, the analysis suggests that the CLCC1Asp25Glu mutant protein exhibits a propensity for increased interactions with cytoplasmic proteins compared to its wild-type counterpart. To corroborate our LC-MS data, we further scrutinized two novel CLCC1 interactors, Calnexin and SigmaR1, chaperone proteins that localize to the ER and MAMs. Through microscopy, we demonstrate that CLCC1 co-localizes with both proteins, thereby validating our initial findings. Moreover, our results reveal that CLCC1 co-localizes with SigmaR1 not merely at the ER, but also at MAMs. These findings reinforce the notion of CLCC1 interacting with MAM proteins at the ER-mitochondria interface, setting the stage for further exploration into how these interactions impact ER or mitochondria function and lead to retinal degenerative disease when impaired.

Transcriptomes reveal microRNAs and mRNAs in different photoperiods influencing cashmere growth in goat

Cashmere goat has a typical characteristic in seasonal growth of cashmere. Studies have shown that one of the main factors affecting the cyclical growth of the cashmere is the photoperiod, however, its molecular mechanism remains unclear. Inner Mongolia Arbas cashmere goat was used to reveal the mRNA-microRNA regulatory mechanisms of cashmere growth in different photoperiod. Skin samples from cashmere goats under light control (short photoperiod) and normal conditions (long photoperiod) were collected. Sequencing was performed after RNA extraction. The differentially expressed miRNA and mRNA expression profiles were successfully constructed. We found 56 significantly differentially expressed known mRNAs (P<0.01) and 14 microRNAs (P<0.05). The association analysis of the microRNAs and mRNAs showed that two differentially expressed miRNAs might be targeted by six differentially expressed genes. Targeting relationships of these genes and miRNAs are revealed and verified. In all, the light control technology provides a new way to promote cashmere growth. Our results provide some references in the cashmere growth and development.

Characterization of West African Crystalline Macular Dystrophy in the Ghanaian Population

OBJECTIVE/PURPOSE

West African Crystalline Maculopathy (WACM) is characterized by the presence of macular hyper-refractile crystal-like deposits. Although the underlying pathophysiology has not been elucidated, a few biological drivers have been proposed. We analysed a large WACM case series to gain a more robust understanding of its features and etiology.

DESIGN

Prospective, Cross-sectional cohort study.

SUBJECTS/PARTICIPANTS

Participants with WACM were selected from the large cohort recruited into the Ghana Age-Related Macular Degeneration Study (Ghana AMD Study).

METHODS

Demographic and detailed medical histories, full ophthalmic examinations, digital colour fundus photographs and optical coherence tomography (OCT) images were obtained. All WACM cases were evaluated by three retina experts. Crystal numbers, location, and distribution were determined. Associations between WACM and Caucasian AMD risk variants were assessed using Firth's bias-reduced logistic regression, including age and gender as covariates.

MAIN OUTCOME MEASURES

Phenotypic features of, and genetic associations with, WACM.

RESULTS

WACM was identified in 106 eyes of 53 participants: 22 were bilateral and 24 unilateral. Grading for AMD was not possible in one eye of seven WACM participants; therefore, laterality was not assessed in these subjects. Thirty-eight participants were female, and 14 male; gender was unrecorded for one participant. Mean age was 68.4 years (range 45-101). OCT demonstrated typical WACM crystals, which were more easily identified at high contrast and predominantly located at the inner limiting membrane (ILM). In eyes with co-pathology, crystals localised deeper in the inner retina with wider retinal distribution over co-pathology lesions. There was no age or gender association. A significant association was observed between the complement factor H (CFH) 402H risk variant and WACM.

CONCLUSION

This study confirms localization of crystals adjacent to the ILM, and distribution over lesions in eyes with co-pathology. Evaluation of OCT images under high contrast allows improved identification. WACM may be associated with the CFH-CFHR5 AMD-risk locus identified amongst Caucasians; however, it is also possible that combination of crystals and the CFH 402H allele increases the risk for developing late AMD. Further analyses using larger sample sizes are warranted to identify causalities between genotype and WACM phenotype.