[Ultrasonographic manifestation and genetic analysis of a fetus with Stickler syndrome]

OBJECTIVE

To carry out genetic analysis for a family with a fetus manifesting micrognathia and a previous history for fetal micromandibular deformity.

METHODS

Systematic ultrasound examination was carried out for the fetus, and the prenatal and postnatal phenotype of the first fetus were retrospectively analyzed. The fetus and his parents were subjected to whole exome sequencing (WES) to identify potential pathogenic variants. Candidate variants were verified by Sanger sequencing.

RESULTS

Fetal ultrasound has indicated micrognathia. The first fetus was found to have micrognathia by prenatal ultrasonography and have featured macrosomia and dyspnea due to with tongue retraction, high palatal arch and small mandibular deformity. WES revealed that the fetus has a harbored a c.3G>C (p.Met1?) variant of the COL2A1 gene, which was inherited from the father who had myopia and retinal detachment.

CONCLUSION

Stickler syndrome is mainly characterized prenatally by micrognathia, in addition with a variety of postnatal anomalies. The c.3G>C (p.Met1?) variant probably underlay the Stickler syndrome in this pedigree.

Retinal Detachment Present at Birth in an Infant With a Novel CTNNB1 Mutation

A full-term neonate was diagnosed on birth with a unilateral total retinal detachment. The contralateral eye had extensive fibrovascular proliferation, temporal dragging, and peripheral nonvascularized retina. Genetic testing confirmed a mutation in the CTNNB1 gene, which has been associated with familiar exudative vitreoretinopathy and phenotypic features including intellectual disability and spastic diplegia. This novel mutation and its associated syndrome should be considered as a cause of retinal detachment presenting in the neonatal period. [Ophthalmic Surg Lasers Imaging Retina 2022; 53:403-405.].

Prevention of Blindness in Stickler Syndrome

Stickler syndromes are inherited conditions caused by abnormalities of structural proteins in the eye, inner ear and cartilage. The risk of retinal detachment, particularly due to the development of giant retinal tears, is high. Stickler syndrome is the most common cause of childhood retinal detachment. Although retinal detachment surgery in the general population has a high success rate, outcomes from surgical repair in Stickler syndrome patients are notoriously poor, providing a strong argument for prophylactic intervention. Variable case selection, absence of molecular genetic sub-typing and inconsistent treatment strategies have all contributed to the historic uncertainty regarding the safety and efficacy of prophylactic treatment. This paper reviews the major published clinical studies that have evaluated different methods and strategies for prophylaxis. Based on the current body of literature, there is extremely strong evidence from cohort comparison studies demonstrating the efficacy and safety of prophylactic retinopexy to reduce, but not eliminate, the risk of retinal detachment in Stickler syndrome patients. It is vital that this body of evidence is provided to Stickler syndrome patients, to enable them to make their own fully informed choice about whether to receive prophylaxis for themselves and particularly on behalf of their affected children, to reduce the risk of retinal detachment.

Dominant Stickler Syndrome

The Stickler syndromes are a group of genetic connective tissue disorders associated with an increased risk of rhegmatogenous retinal detachment, deafness, cleft palate, and premature arthritis. This review article focuses on the molecular genetics of the autosomal dominant forms of the disease. Pathogenic variants in COL2A1 causing Stickler syndrome usually result in haploinsufficiency of the protein, whereas pathogenic variants of type XI collagen more usually exert dominant negative effects. The severity of the disease phenotype is thus dependent on the location and nature of the mutation, as well as the normal developmental role of the respective protein.

Pediatric Retinal Detachment in Homozygous Protein C Deficiency: Genetic and Phenotypic Description of a Single Family

Homozygous protein C deficiency is a rare hypercoagulability disorder. This study describes the ocular manifestations and the genetic background in a family with two affected children. This is a retrospective review of ophthalmic examinations, investigations, genetic testing, and blood work-up of two children with homozygous protein C deficiency from a single family. A family with a positive history of consanguineous marriage was found to have two affected children with homozygous protein C deficiency. Abnormal visual behavior was the presenting symptom. Both children had bilateral total tractional retinal detachments at presentation. Skin manifestations included episodes of discoloration and bruising. Laboratory work-up revealed absent protein C activity. Genetic testing confirmed the presence of a homozygous pathogenic mutation in protein C gene (NM_000312.3: c.1297G>A: p.Gly433Ser). Homozygous protein C deficiency should be considered in the differential diagnosis of early-onset tractional retinal detachment in infancy. Although rare, the ophthalmologist may be the first to encounter the condition, and treatment with protein C replacement or anticoagulants may be life-saving. Examination under anesthesia with fluorescein angiography and laser treatment early in life may be warranted to preserve vision. [Ophthalmic Surg Lasers Imaging Retina. 2022;53:293-296.].

A Splicing Mutation in Slc4a5 Results in Retinal Detachment and Retinal Pigment Epithelium Dysfunction

Fluid and solute transporters of the retinal pigment epithelium (RPE) are core components of the outer blood-retinal barrier. Characterizing these transporters and their role in retinal homeostasis may provide insights into ocular function and disease. Here, we describe RPE defects in tvrm77 mice, which exhibit hypopigmented patches in the central retina. Mapping and nucleotide sequencing of tvrm77 mice revealed a disrupted 5' splice donor sequence in Slc4a5, a sodium bicarbonate cotransporter gene. Slc4a5 expression was reduced 19.7-fold in tvrm77 RPE relative to controls, and alternative splice variants were detected. SLC4A5 was localized to the Golgi apparatus of cultured human RPE cells and in apical and basal membranes. Fundus imaging, optical coherence tomography, microscopy, and electroretinography (ERG) of tvrm77 mice revealed retinal detachment, hypopigmented patches corresponding to neovascular lesions, and retinal folds. Detachment worsened and outer nuclear layer thickness decreased with age. ERG a- and b-wave response amplitudes were initially normal but declined in older mice. The direct current ERG fast oscillation and light peak were reduced in amplitude at all ages, whereas other RPE-associated responses were unaffected. These results link a new Slc4a5 mutation to subretinal fluid accumulation and altered light-evoked RPE electrophysiological responses, suggesting that SLC4A5 functions at the outer blood-retinal barrier.

Myosin 1f-mediated activation of microglia contributes to the photoreceptor degeneration in a mouse model of retinal detachment

Photoreceptor death and neurodegeneration is the leading cause of irreversible vision loss. The inflammatory response of microglia plays an important role in the process of neurodegeneration. In this study, we chose retinal detachment as the model of photoreceptor degeneration. We found Myosin 1f was upregulated after retinal detachment, and it was specifically expressed in microglia. Deficiency of myosin 1f protected against photoreceptor apoptosis by inhibiting microglia activation. The elimination of microglia can abolish the protective effect of myosin 1f deficiency. After stimulation by LPS, microglia with myosin 1f deficiency showed downregulation of the MAPK and AKT pathways. Our results demonstrated that myosin 1f plays a crucial role in microglia-induced neuroinflammation after retinal injury and photoreceptor degeneration by regulating two classic inflammatory pathways and thereby decreasing the expression of inflammatory cytokines. Knockout of myosin 1f reduces the intensity of the immune response and prevents cell death of photoreceptor, suggesting that myosin 1f can be inhibited to prevent a decline in visual acuity after retinal detachment.

The incidence and awareness of Rhegmatogenous retinal detachment in Pakistani population

Retinal detachment (RD) describes the separation of neurosensory retina from the underlying pigment epithelium. There are various methods of treating RD but in many cases, an unusual delay between occurrence of retinal detachment and surgery has been observed. This study was conducted to find the extent of factors involved in delay in surgery. This cross sectional study was carried out at LRBT Eye Hospital, Lahore for 6 months. The non-probability, consecutive sampling technique was used. The demographic information was recorded. The patients were asked for causes of delay in retinal detachment surgery and all factors were measured. Data was analyzed by SPSS version 21. The mean age of patients was 52±9.86 years; the male to female ratio was 1.5:1. About 9.3% patients said that they do not know where to go, 30% patients thought that it was not a severe condition,36.4% patients thought that it would self-heal,17.1% patients didn't go to the doctor due to financial constraints whereas 7.1% patients did not have VR ophthalmologist near their residence. Statistically significant difference was found between the factors and education level of the patients i.e. p-value<0.05. Our study results concluded that people needed to be educated regarding the importance of retinal detachment and surgical procedures and complications associated with it.

Conditional Knock out of High-Mobility Group Box 1 (HMGB1) in Rods Reduces Autophagy Activation after Retinal Detachment

After retinal detachment (RD), the induction of autophagy protects photoreceptors (PR) from apoptotic cell death. The cytoplasmic high-mobility group box 1 (HMGB1) promotes autophagy. We previously demonstrated that the deletion of HMGB1 from rod PRs results in a more rapid death of these cells after RD. In this work, we tested the hypothesis that the lack of HMGB1 accelerates PR death after RD due to the reduced activation of protective autophagy in the retina after RD. The injection of 1% hyaluronic acid into the subretinal space was used to create acute RD in mice with a rhodopsin-Cre-mediated conditional knockout (cKO) of HMGB1 in rods (HMGB1Δrod) and littermate controls. RD sharply increased the number of apoptotic cells in the outer nuclear layer (ONL), and this number was further increased in HMGB1Δrod mouse retinas. The activation of autophagy after RD was reduced in the HMGB1Δrod mouse retinas compared to controls, as evidenced by diminished levels of autophagy regulatory proteins LC3-II, Beclin1, ATG5/12, and phospho-ATG16L1. The cKO of HMGB1 in rods increased the expression of Fas and the Bax/Bcl-2 ratio in detached retinas, promoting apoptotic cell death. In conclusion, endogenous HMGB1 facilitates autophagy activation in PR cells following RD to promote PR cell survival and reduce programmed apoptotic cell death.

Pleiotropy of a Stickler syndrome genotype

PURPOSE

To report a case of pleiotropy in the COL2A1 gene typically associated with Stickler Syndrome Type 1.

OBSERVATIONS

A patient with a confirmed mutation of the COL2A1 gene presented with an isolated retinitis pigmentosa phenotype.

CONCLUSIONS

The mutated COL2A1 gene in Stickler Syndrome Type 1 represents a site of pleiotropy, highlighting a change in phenotype across the same genotype potentially due to tissue alternative splicing.

Cleft palate morphology, genetic etiology, and risk of mortality in infants with Robin sequence

Robin sequence (RS) has many genetic and nongenetic causes, including isolated Robin sequence (iRS), Stickler syndrome (SS), and other syndromes (SyndRS). The purpose of this study was to determine if the presence and type of cleft palate varies between etiologic groups. A secondary endpoint was to determine the relationship of etiologic group, cleft type, and mortality. Retrospective chart review of patients with RS at two high-volume craniofacial centers. 295 patients with RS identified. CP was identified in 97% with iRS, 95% with SS, and 70% of those with SyndRS (p < .0001). U-shaped CP was seen in 86% of iRS, 82% with SS, but only 27% with SyndRS (p < .0001). At one institution, 12 children (6%) with RS died, all from the SyndRS group (p < .0001). All died due to medical comorbidities related to their syndrome. Only 25% of children who died had a U-shaped CP. The most common palatal morphology among those who died was an intact palate. U-shaped CP was most strongly associated with iRS and SS, and with a lower risk of mortality. RS with submucous CP, cleft lip and palate or intact palate was strongly suggestive of an underlying genetic syndrome and higher risk of mortality.

Identification of a variant in NDP associated with X-linked retinal dysplasia in the English cocker spaniel dog

Purpose

Three related male English Cocker Spaniels (ECS) were reported to be congenitally blind. Examination of one of these revealed complete retinal detachment. A presumptive diagnosis of retinal dysplasia (RD) was provided and pedigree analysis was suggestive of an X-linked mode of inheritance. We sought to investigate the genetic basis of RD in this family of ECS.

Methods

Following whole genome sequencing (WGS) of the one remaining male RD-affected ECS, two distinct investigative approaches were employed: a candidate gene approach and a whole genome approach. In the candidate gene approach, COL9A2, COL9A3, NHEJ1, RS1 and NDP genes were investigated based on their known associations with RD and retinal detachment in dogs and humans. In the whole genome approach, affected WGS was compared with 814 unaffected canids to identify candidate variants, which were filtered based on appropriate segregation and predicted pathogenic effects followed by subsequent investigation of gene function. Candidate variants were tested for appropriate segregation in the ECS family and association with disease was assessed using samples from a total of 180 ECS.

Results

The same variant in NDP (c.653_654insC, p.Met114Hisfs*16) that was predicted to result in 15 aberrant amino acids before a premature stop in norrin protein, was identified independently by both approaches and was shown to segregate appropriately within the ECS family. Association of this variant with X-linked RD was significant (P = 0.0056).

Conclusions

For the first time, we report a variant associated with canine X-linked RD. NDP variants are already known to cause X-linked RD, along with other abnormalities, in human Norrie disease. Thus, the dog may serve as a useful large animal model for research.

Post-hoc analysis of single nucleotide polymorphism profile for eyes with vascularized pigment epithelial detachment due to ARMD

INTRODUCTION

This post-hoc case-control study compares single nucleotide polymorphism (SNP) profile of eyes with vascularized pigment epithelial detachment (vPED) due to age-related macular degeneration (ARMD) with: (1) Control-1 eyes (no ARMD and AREDS Severity Scale 0); and (2) Control-2 eyes (drusen or AREDS Severity Scale 2). SNP profile of High Responders (HR) was also compared with Low Responders (LR) to ranibizumab.

METHODS

Blood samples from 40 patients with vPED treated with ranibizumab were sent for SNP-specific genotype analysis for comparison of variant allele frequencies of 23 SNPs associated with ARMD (VAF) to VAF in 184 Control-1 eyes, and VAF in 85 Control-2 eyes. VAF of HR-50 (⩾50% decrease in PED height) and VAF of HR-75 (⩾75% decrease in PED height) were also compared with VAF of LR.

RESULTS

These SNPs were more frequent in vPED than Control-1 eyes: APOE rs4420638 (A/G), HTRA1 rs104904924 (G/T), VEGF rs943080 (T/C), CFH rs1061170 (T/C), CFH rs2274700 (C/T), CFH rs10737680 (A/C), CFH rs10801555 (G/A). These SNPs were more frequent in vPED than Control-2 eyes: APOE rs4420638 (A/G), CFI rs4698775 (G/T), COL15A1/TGFBR1 rs334353 (T/G). FRK rs3812111 (T/A) was more frequent in HR-50 and HR-75 eyes compared with LR.

CONCLUSION

Seven SNPs were more frequent in vPED eyes than non-ARMD eyes, and three SNPs were more frequent in vPED eyes than drusen eyes. Adjusting for multiplicity, only CFH rs2274700 (C/T) was significant for first comparison, and only COL15A1/TGFBR1 rs334353 (T/G) was significant for second comparison. APOE rs4420638 (A/G) was the single SNP more frequently linked to vPED eyes for both comparisons. FRK rs3812111 (T/A) was consistently associated with high responders.

Two AOS genes attributed to familial exudative vitreoretinopathy with microcephaly: Two case reports

RATIONALE

Familial exudative vitreoretinopathy (FEVR) is an inherited disorder, which is mostly reported to be associated with the mutation of genes involved in the Wnt signaling pathway related to β-catenin. To the best of our knowledge, the involvement of Adams-Oliver syndrome (AOS) genes in FEVR patients have not been reported before.

PATIENT CONCERNS

Two patients with FEVR presented with microcephaly. One of them showed slight scarring of the scalp vertex which is a typical manifestation of AOS. The whole exon sequencing confirmed the diagnosis of AOS with 2 AOS-gene mutations at DOCK6 and ARHGAP31. Further clinical examination revealed that their parents with the same mutations showed FEVR-like vascular anomalies.

DIAGNOSIS

Both patients were diagnosed with AOS through whole exon sequencing, and they presented with some FEVR-like retinopathy including retinal detachment.

INTERVENTIONS

Both patients received vitrectomy for tractional retinal detachment with proliferative vitreoretinopathy. During the follow-up, 1 patient received additional laser photocoagulation for tractional retinal detachment.

OUTCOMES

The 2 patients remained stable in the latest follow up after the treatment.

LESSONS

Microcephaly could be associated with some form of retinopathy. We proposed that mutation of DOCK6 and ARHGAP31 genes could be the possible cause of FEVR associated with microcephaly. Our study suggested that these genes may be candidate genes of FEVR.

Involvement of the Retinal Pigment Epithelium in the Development of Retinal Lattice Degeneration

Lattice degeneration involves thinning of the retina that occurs over time. Here we performed an immunohistological study of tissue sections of human peripheral retinal lattice degeneration to investigate if retinal pigment epithelium (RPE) cells are involved in the pathogenesis of this condition. In two cases of retinal detachment with a large tear that underwent vitreous surgery, retinal lattice degeneration tissue specimens were collected during surgery. In the obtained specimens, both whole mounts and horizontal section slices were prepared, and immunostaining was then performed with hematoxylin and antibodies against glial fibrillary acidic protein (GFAP), RPE-specific protein 65 kDa (RPE65), pan-cytokeratin (pan-CK), and CK18. Hematoxylin staining showed no nuclei in the center of the degenerative lesion, thus suggesting the possibility of the occurrence of apoptosis. In the degenerative lesion specimens, GFAP staining was observed in the center, RPE65 staining was observed in the slightly peripheral region, and pan-CK staining was observed in all areas. However, no obvious CK18 staining was observed. In a monkey retina used as the control specimen of a normal healthy retina, no RPE65 or pan-CK staining was observed in the neural retina. Our findings suggest that migration, proliferation, and differentiation of RPE cells might be involved in the repair of retinal lattice degeneration.

Position of macula lutea and presence of proliferative vitreoretinopathy affect vitreous cytokine expression in rhegmatogenous retinal detachment

Our purpose was to evaluate the concentrations of vitreous cytokines in patients with rhegmatogenous retinal detachment (RRD). We hypothesized that patients with macula on RRD have lower levels of cytokines compared to patients with macula off RRD and proliferative vitreoretinopathy (PVR). Vitreous fluids were collected during 23G pars plana vitrectomy from 58 eyes of 58 patients. Indication for vitrectomy included macula off and macula on RRD, PVR, and idiopathic epiretinal membrane (ERM). A multiplex chemiluminescent immunoassay was performed to measure the concentrations of 48 cytokines, chemokines, and growth factors. Levels of HGF, IL-6, IL-8, IL-16, IFN-gamma, MCP-1, and MIF were significantly higher in all groups of retinal detachment compared to ERM. Levels of CTACK, eotaxin, G-CSF, IP-10, MIG, SCF, SCGF-beta, SDF-1alpha were significantly higher in PVR compared to macula on RRD and ERM. Levels of IL-1ra, IL-5, IL-9, M-CSF, MIP-1alpha, and TRIAL were significantly higher in PVR compared to macula on RRD. Our results indicate that the position of macula lutea and the presence of PVR significantly influence vitreous cytokine expression. The detected proteins may serve as biomarkers to estimate the possibility of PVR formation and may help to invent personalized therapeutic strategies to slow down or prevent PVR.

MicroRNAs in the Vitreous Humor of Patients with Retinal Detachment and a Different Grading of Proliferative Vitreoretinopathy: A Pilot Study

Purpose

Although the expression of microRNAs (miRNAs) in retinal pigment epithelial (RPE) cells undergoing epithelial-mesenchymal transition (EMT) is involved in the pathogenesis of proliferative vitreoretinopathy (PVR), its expression in the vitreous of patients with primary retinal detachment (RD) and different PVR grading has not yet been investigated. We assessed the expression of miRNAs in the vitreous humor (VH) of patients diagnosed with RD and different grading of PVR.

Methods

The VH was extracted from the core of the vitreous chamber in patients who had undergone standard vitrectomy for primary RD. RNA was extracted and TaqMan Low-Density Arrays (TLDAs) were used for miRNA profiling that was performed by single TaqMan assays. A gene ontology (GO) analysis was performed on the differentially expressed miRNAs.

Results

A total of 15 eyes with RD, 3 eyes for each grade of PVR (A, B, C, and D) and 3 from unaffected individuals, were enrolled in this prospective comparative study. Twenty miRNAs were altered in the comparison among pathological groups. Interestingly, the expression of miR-143-3p, miR-224-5p, miR-361-5p, miR-452-5p, miR-486-3p, and miR-891a-5p increased with the worsening of PVR grading. We also identified 34 miRNAs showing differential expression in PVR compared to control vitreous samples. GO analysis showed that the deregulated miRNAs participate in processes previously associated with PVR pathogenesis.

Conclusions

The present pilot study suggested that dysregulated vitreal miRNAs may be considered as a biomarker of PVR and associated with the PVR-related complications in patients with RD.

Translational Relevance

The correlation between vitreal miRNAs and the pathological phenotypes are essential to identify the novel miRNA-based mechanisms underlying the PVR disease that would improve the diagnosis and treatment of the condition.

COL2A1 protective variant reduces sporadic rhegmatogenous retinal detachment severity

Rhegmatogenous retinal detachment (RRD) is the most common type of RD, the separation of neurosensory retina from the underlying retinal pigment epithelium. The RRD patients can be benefited from appropriate treatment if detected early, especially for the people predicted at high risk. In this study, we aimed to investigate the genetic association and clinical correlation of collagen type II alpha 1 (COL2A1) variants with sporadic RRD in a southern Chinese population. Totally 156 RRD patients and 254 control subjects were recruited, and 12 COL2A1 tag single nucleotide polymorphisms were genotyped by the TaqMan assay. The RRD patients had poorer visual acuity (P < 0.001) and lower intraocular pressure (IOP; P < 0.001) in their surgical eyes compared to the fellow eyes. The COL2A1 rs1793958 variant was significantly associated with RRD in the genotypic (P = 0.024), allelic (P = 0.011, odds ratio (OR) = 0.669), recessive (P = 0.011, OR = 0.384) and homozygous models (P = 0.007, OR = 0.348). RRD patients carrying the rs1793958 G allele had smaller retinal detachment area (P = 0.041) and smaller IOP differences (P = 0.046) between the surgical and fellow eyes compared to those carrying the wildtype AA genotype. In summary, this study revealed that the COL2A1 rs1793958 variant is associated with reduced risk of sporadic RRD, and patients carrying rs1793958 G allele have lower RRD severity.

Intrafamilial variability of XYLT2-related spondyloocular syndrome

Spondyloocular syndrome is characterized by generalized osteoporosis, multiple fractures and severe ocular findings. The causative XYLT2 mutations have recently been identified with the use of whole exome sequencing. We report on two siblings with spondyloocular syndrome who presented with varying clinical severity. A novel XYLT2 missense mutation was detected in a region evolutionary conserved across the species. This report along with the previous reports demonstrates that variable expressivity may be possible even within the same family. These two siblings with a novel mutation further expand the clinical and mutational spectrum of spondyloocular syndrome.

Clinical, histopathological and genetic characterisation of oculoskeletal dysplasia in the Northern Inuit Dog

Seven Northern Inuit Dogs (NID) were diagnosed by pedigree analysis with an autosomal recessive inherited oculoskeletal dysplasia (OSD). Short-limbed dwarfism, angular limb deformities and a variable combination of macroglobus, cataracts, lens coloboma, microphakia and vitreopathy were present in all seven dogs, while retinal detachment was diagnosed in five dogs. Autosomal recessive OSD caused by COL9A3 and COL9A2 mutations have previously been identified in the Labrador Retriever (dwarfism with retinal dysplasia 1-drd1) and Samoyed dog (dwarfism with retinal dysplasia 2-drd2) respectively; both of those mutations were excluded in all affected NID. Nine candidate genes were screened in whole genome sequence data; only one variant was identified that was homozygous in two affected NID but absent in controls. This variant was a nonsense single nucleotide polymorphism in COL9A3 predicted to result in a premature termination codon and a truncated protein product. This variant was genotyped in a total of 1,232 dogs. All seven affected NID were homozygous for the variant allele (T/T), while 31/116 OSD-unaffected NID were heterozygous for the variant (C/T) and 85/116 were homozygous for the wildtype allele (C/C); indicating a significant association with OSD (p = 1.41x10-11). A subset of 56 NID unrelated at the parent level were analysed to determine an allele frequency of 0.08, estimating carrier and affected rates to be 15% and 0.6% respectively in NID. All 1,109 non-NID were C/C, suggesting the variant is rare or absent in other breeds. Expression of retinal mRNA was similar between an OSD-affected NID and OSD-unaffected non-NID. In conclusion, a nonsense variant in COL9A3 is strongly associated with OSD in NID, and appears to be widespread in this breed.

LOXL3 Function Beyond Amino Oxidase and Role in Pathologies, Including Cancer

Lysyl oxidase like 3 (LOXL3) is a copper-dependent amine oxidase responsible for the crosslinking of collagen and elastin in the extracellular matrix. LOXL3 belongs to a family including other members: LOX, LOXL1, LOXL2, and LOXL4. Autosomal recessive mutations are rare and described in patients with Stickler syndrome, early-onset myopia and non-syndromic cleft palate. Along with an essential function in embryonic development, multiple biological functions have been attributed to LOXL3 in various pathologies related to amino oxidase activity. Additionally, various novel roles have been described for LOXL3, such as the oxidation of fibronectin in myotendinous junction formation, and of deacetylation and deacetylimination activities of STAT3 to control of inflammatory response. In tumors, three distinct roles were described: (1) LOXL3 interacts with SNAIL and contributes to proliferation and metastasis by inducing epithelial-mesenchymal transition in pancreatic ductal adenocarcinoma cells; (2) LOXL3 is localized predominantly in the nucleus associated with invasion and poor gastric cancer prognosis; (3) LOXL3 interacts with proteins involved in DNA stability and mitosis completion, contributing to melanoma progression and sustained proliferation. Here we review the structure, function and activity of LOXL3 in normal and pathological conditions and discuss the potential of LOXL3 as a therapeutic target in various diseases.

P38 inhibition reverses TGFβ1 and TNFα-induced contraction in a model of proliferative vitreoretinopathy

Proliferative vitreoretinopathy (PVR) is a metaplasia in the vitreous of the eye manifested by the transformation of retinal pigment epithelial (RPE) cells and the development of contracting epiretinal membranes (ERM), which lead to retinal detachment and vision loss. While TGFβ1 and TNFα have been associated with PVR, here we show that these cytokines act synergistically to induce an aggressive contraction phenotype on adult human (ah)RPE. Connected RPE detach upon contraction and form motile membranes that recruit more cells. TGFβ1 and TNFα (TNT)-induced contracting membranes uniquely express muscle and extracellular rearrangement genes. Whole transcriptome RNA sequencing of patient-dissected PVR membranes showed activation of the p38-MAPK signaling pathway. Inhibition of p38 during TNT treatment blocks ahRPE transformation and membrane contraction. Furthermore, TNT-induced membrane contractility can be reversed by p38 inhibition after induction. Therefore, targeting the p38-MAPK pathway may have therapeutic benefits for patients with PVR even after the onset of contracting ERMs.