Wnt signaling controls pro-regenerative Collagen XII in functional spinal cord regeneration in zebrafish

The inhibitory extracellular matrix in a spinal lesion site is a major impediment to axonal regeneration in mammals. In contrast, the extracellular matrix in zebrafish allows substantial axon re-growth, leading to recovery of movement. However, little is known about regulation and composition of the growth-promoting extracellular matrix. Here we demonstrate that activity of the Wnt/beta-catenin pathway in fibroblast-like cells in the lesion site is pivotal for axon re-growth and functional recovery. Wnt/beta-catenin signaling induces expression of col12a1a/b and deposition of Collagen XII, which is necessary for axons to actively navigate the non-neural lesion site environment. Overexpression of col12a1a rescues the effects of Wnt/beta-catenin pathway inhibition and is sufficient to accelerate regeneration. We demonstrate that in a vertebrate of high regenerative capacity, Wnt/beta-catenin signaling controls the composition of the lesion site extracellular matrix and we identify Collagen XII as a promoter of axonal regeneration. These findings imply that the Wnt/beta-catenin pathway and Collagen XII may be targets for extracellular matrix manipulations in non-regenerating species

CRISPLD2 variants including a C471T silent mutation may contribute to nonsyndromic cleft lip with or without cleft palate

Objective: To assess the association between nonsyndromic (NS) cleft lip with or without cleft palate (CL(P)) and single-nucleotide polymorphisms (SNPs) within the CRISPLD2 gene (cysteine-rich secretory protein LCCL domain containing 2). Design: Four SNPs within the CRISPLD2 gene domain (rs1546124, rs8061351, rs2326398, rs4783099) were genotyped to test for association via family-based association methods. Participants: A total of 5826 individuals from 1331 families in which one or more family member is affected with CL(P). Results: Evidence of association was seen for SNP rs1546124 in U.S. (p = .02) and Brazilian (p = .04) Caucasian cohorts. We also found association of SNP rs1546124 with cleft palate alone (CP) in South Americans (Guatemala and ECLAMC) and combined Hispanics (Guatemala, ECLAMC, and Texas Hispanics; p = .03 for both comparisons) and with both cleft lip with cleft palate (CLP; p = .04) and CL(P) (p = .02) in North Americans. Strong evidence of association was found for SNP rs2326398 with CP in Asian populations (p = .003) and with CL(P) in Hispanics (p = .03) and also with bilateral CL(P) in Brazilians (p = .004). In Brazilians, SNP rs8061351 showed association with cleft subgroups incomplete CL(P) (p = .004) and unilateral incomplete CL(P) (p = .003). Prediction of SNP functionality revealed that the C allele in the C471T silent mutation (overrepresented in cases with CL(P) presents two putative exonic splicing enhancer motifs and creates a binding site AP-2 alpha, a transcription factor involved in craniofacial development. Conclusions: Our results support the hypothesis that variants in the CRISPLD2 gene may be involved in the etiology of NS CL(P)

Genomic screening identifies novel linkages and provides further evidence for a role of MYH9 in nonsyndromic cleft lip and palate

Nonsyndromic cleft lip with or without cleft palate (NSCLP) is a common birth anomaly that requires prolonged multidisciplinary rehabilitation. Although variation in several genes has been identified as contributing to NSCLP, most of the genetic susceptibility loci have yet to be defined. To identify additional contributory genes, a high-throughput genomic scan was performed using the Illumina Linkage IVb Panel platform. We genotyped 6008 SNPs in nine non-Hispanic white NSCLP multiplex families and a single large African-American NSCLP multiplex family. Fourteen chromosomal regions were identified with LOD>1.5, including six regions not previously reported. Analysis of the data from the African-American and non-Hispanic white families revealed two likely chromosomal regions: 8q21.3–24.12 and 22q12.2–12.3 with LOD scores of 2.98 and 2.66, respectively. On the basis of biological function, syndecan 2 (SDC2) and growth differentiation factor 6 (GDF6) in 8q21.3–24.12 and myosin heavy-chain 9, non-muscle (MYH9) in 22q12.2–12.3 were selected as candidate genes. Association analyses from these genes yielded marginally significant P-values for SNPs in SDC2 and GDF6 (0.01≤P<0.05). Evidence for an altered transmission was found for four MYH9 SNPs (P<0.01). SNP rs1002246 exhibited altered transmission by all analytic methods. However, analysis of two SNP MYH9 haplotypes did not identify a single high-risk haplotype. Our results confirm a previous report that 8q21.3–24.12 may harbor a clefting gene and identify 22q12.2–12.3 as a new candidate region that contains MYH9. Most importantly, we confirm the previous report of an association with MYH9

Cleft lip and palate: Understanding genetic and environmental influences

Clefts of the lip and/or palate (CLP) are common birth defects of complex etiology. CLP can occur in isolation or as part of a broad range of chromosomal, Mendelian, or teratogenic syndromes. Although there has been marked progress in identifying genetic and environmental triggers for syndromic CLP, the etiology of the more common non-syndromic (isolated) forms remains poorly characterized. Recently, using a combination of epidemiology, careful phenotyping, genome-wide association studies and analysis of animal models, several distinct genetic and environmental risk factors have been identified and confirmed for non-syndromic CLP. These findings have advanced our understanding of developmental biology and created new opportunities for clinical translation research