Knockdown of hspg2 is associated with abnormal mandibular joint formation and neural crest cell dysfunction in zebrafish

Abstract

Background Heparan sulfate proteoglycan 2 (HSPG2) encodes for perlecan, a large proteoglycan that plays an important role in cartilage formation, cell adhesion, and basement membrane stability. Mutations in HSPG2 have been associated with Schwartz-Jampel Syndrome (SJS) and Dyssegmental Dysplasia Silverman-Handmaker Type (DDSH), two disorders characterized by skeletal abnormalities. These data indicate a function for HSPG2 in cartilage development/maintenance. However, the mechanisms in which HSPG2 regulates cartilage development are not completely understood. Here, we explored the relationship between this gene and craniofacial development through morpholino-mediated knockdown of hspg2 using zebrafish. Results Knockdown of hspg2 resulted in abnormal development of the mandibular jaw joint at 5 days post fertilization (DPF). We surmised that defects in mandible development were a consequence of neural crest cell (NCC) dysfunction, as these multipotent progenitors produce the cartilage of the head. Early NCC development was normal in morphant animals as measured by distal-less homeobox 2a (dlx2a) and SRY-box transcription factor 10 (sox10) expression at 1 DPF. However, subsequent analysis at later stages of development (4 DPF) revealed a decrease in the number of Sox10 + and Collagen, type II, alpha 1a (Col2a1a)+ cells within the mandibular jaw joint region of morphants relative to random control injected embryos. Concurrently, morphants showed a decreased expression of nkx3.2, a marker of jaw joint formation, at 4 DPF. Conclusions Collectively, these data suggest a complex role for hspg2 in jaw joint formation and late stage NCC differentiation.

Hemifacial microsomia is linked to a rare homozygous variant V162I in FRK and validated in zebrafish

“…We showed that Frk is expressed in the affected craniofacial tissues (Meckel's cartilage center or mandible bone) during the developmental period (Ling et al, 2017; Sisson et al, 2015). Furthermore, we demonstrated that morpholino‐knockdown of frk in embryonic zebrafish results in impaired development of Meckel's cartilage and associated tissues as well as abnormal mandibular joint formation, consistent with the affected individual's craniofacial developmental defects and other related disorders that have been modeled in zebrafish (Castellanos et al, 2021; Liu et al, 2021; Wang et al, 2020). These observed defects are consistent with improper regulation of sensory neurons in invertebrate systems and cranial neural crest cells (CNCC) in vertebrate systems, which may result in failure migrate to and differentiate into appropriate tissue in the head regions, including the pharyngeal arches, cartilage, and bone (Bhatt et al, 2013).…”

“…Furthermore, we demonstrated that morpholino-knockdown of frk in embryonic zebrafish results in impaired development of Meckel's cartilage and associated tissues as well as abnormal mandibular joint formation, consistent with the affected individual's craniofacial developmental defects and other related disorders that have been modeled in zebrafish (Castellanos et al, 2021;Liu et al, 2021;Wang et al, 2020) As SRC kinase family members, human FRK and FYN (OMIM *137025) share high identity/similarity in protein sequence (46%/59%) and have been linked to tumorigenesis due to their overexpression or somatic mutations (OMIM *606573). Knockout of the mouse ortholog gene Frk was found to cause significant decreases in the circulating levels of T3 and euthyroid sick syndrome (ESS) (Chandrasekharan et al, 2002).…”

Case report: genetic analysis of a child with 18q deletion syndrome and developmental dysplasia of the hip

“…HSPG2 encodes for perlecan, a large proteoglycan that plays an important role in cartilage formation, cell adhesion, and basement membrane stability. The diseases related to HSPG2 mutations mainly include dyssegmental dysplasia Silverman-Handmaker type (DDHS) and Schwartz Jampel syndrome type 1, both of which are autosomal recessive diseases [ 24 ]. The clinical features of DDHS include facial dysmorphisms, GU abnormalities, severe short stature, decreased joint mobility, cleft palate and club feet [ 25 ].…”