Zebrafish models of alx-linked frontonasal dysplasia reveal a role for Alx1 and Alx3 in the anterior segment and vasculature of the developing eye.

The cellular and genetic mechanisms that coordinate formation of facial sensory structures with surrounding skeletal and soft tissue elements remain poorly understood. Alx1, a homeobox transcription factor, is a key regulator of midfacial morphogenesis. ALX1 mutations in humans are linked to severe congenital anomalies of the facial skeleton (frontonasal dysplasia, FND) with malformation or absence of eyes and orbital contents (micro- and anophthalmia). Zebrafish with loss-of-function alx1 mutations develop with craniofacial and ocular defects of variable penetrance, likely due to compensatory upregulation in expression of a paralogous gene, alx3. Here we show that zebrafish alx1;alx3 mutants develop with highly penetrant cranial and ocular defects that resemble human ALX1-linked FND. alx1 and alx3 are expressed in anterior cranial neural crest (aCNC), which gives rise to the anterior neurocranium (ANC), anterior segment structures of the eye and vascular pericytes. Consistent with a functional requirement for alx genes in aCNC, alx1; alx3 mutants develop with nearly absent ANC and grossly aberrant hyaloid vasculature and ocular anterior segment, but normal retina. In vivo lineage labeling identified a requirement for alx1 and alx3 during aCNC migration, and transcriptomic analysis suggested oxidative stress response as a key target mechanism of this function. Oxidative stress is a hallmark of fetal alcohol toxicity, and we found increased penetrance of facial and ocular malformations in alx1 mutants exposed to ethanol, consistent with a protective role for alx1 against ethanol toxicity. Collectively, these data demonstrate a conserved role for zebrafish alx genes in controlling ocular and facial development, and a novel role in protecting these key midfacial structures from ethanol toxicity during embryogenesis. These data also reveal novel roles for alx genes in ocular anterior segment formation and vascular development and suggest that retinal deficits in alx mutants may be secondary to aberrant ocular vascularization and anterior segment defects. This study establishes robust zebrafish models for interrogating conserved genetic mechanisms that coordinate facial and ocular development, and for exploring gene--environment interactions relevant to fetal alcohol syndrome.

ALX1-related frontonasal dysplasia results from defective neural crest cell development and migration.

A pedigree of subjects presented with frontonasal dysplasia (FND). Genome sequencing and analysis identified a p.L165F missense variant in the homeodomain of the transcription factor ALX1 which was imputed to be pathogenic. Induced pluripotent stem cells (iPSC) were derived from the subjects and differentiated to neural crest cells (NCC). NCC derived from ALX1L165F/L165F iPSC were more sensitive to apoptosis, showed an elevated expression of several neural crest progenitor state markers, and exhibited impaired migration compared to wild-type controls. NCC migration was evaluated in vivo using lineage tracing in a zebrafish model, which revealed defective migration of the anterior NCC stream that contributes to the median portion of the anterior neurocranium, phenocopying the clinical presentation. Analysis of human NCC culture media revealed a change in the level of bone morphogenic proteins (BMP), with a low level of BMP2 and a high level of BMP9. Soluble BMP2 and BMP9 antagonist treatments were able to rescue the defective migration phenotype. Taken together, these results demonstrate a mechanistic requirement of ALX1 in NCC development and migration.

Dynamic cyclic compression modulates the chondrogenic phenotype in human chondrocytes from late stage osteoarthritis.

Human osteoarthritic chondrocytes (hOACs) are characterized by their "dedifferentiated" and catabolic phenotype and lack the ability for restoring their inherent functions by themselves. Here we investigated whether extrinsically supplemented mechanical signal via compression loading would affect the phenotype of hOACs. Specifically, we applied cyclic compression loading on cultured hOACs-collagen constructs and measured the expression of the major chondrogenic factors, cell-matrix interaction molecules and matrix degradation enzymes. Dynamic compression loading stimulates the expression and nuclear localization of sox9 in hOACs and reduces the catabolic events via downregulated expression of collagenases. These results contribute to better understanding towards mechanoregulation of hOACs.

Microencapsulation of Neuroblastoma Cells and Mesenchymal Stromal Cells in Collagen Microspheres: A 3D Model for Cancer Cell Niche Study.

There is a growing trend for researchers to use in vitro 3D models in cancer studies, as they can better recapitulate the complex in vivo situation. And the fact that the progression and development of tumor are closely associated to its stromal microenvironment has been increasingly recognized. The establishment of such tumor supportive niche is vital in understanding tumor progress and metastasis. The mesenchymal origin of many cells residing in the cancer niche provides the rationale to include MSCs in mimicking the niche in neuroblastoma. Here we co-encapsulate and co-culture NBCs and MSCs in a 3D in vitro model and investigate the morphology, growth kinetics and matrix remodeling in the reconstituted stromal environment. Results showed that the incorporation of MSCs in the model lead to accelerated growth of cancer cells as well as recapitulation of at least partially the tumor microenvironment in vivo. The current study therefore demonstrates the feasibility for the collagen microsphere to act as a 3D in vitro cancer model for various topics in cancer studies.

Predicting inadequate spirometry technique and the use of FEV1/FEV3 as an alternative to FEV1/FVC for patients with mild cognitive impairment.

INTRODUCTION AND OBJECTIVES: Some patients cannot perform forced vital capacity (FVC). We conducted a study to answer three questions: Can the ability to perform components of spirometry be predicted by the Mini Mental State Examination (MMSE)? What proportion of subjects can perform forced expiratory volume in 3 s (FEV3) but not FVC? Does the forced expiratory volume in 1 s (FEV1)/FEV3 ratio concord with FEV1/FVC ratio in patients with airflow obstruction? METHODS: We conducted a prospective observational study of 267 patients with a mean age of 79 years, including subjects with indicators of frailty. They performed spirometry and the MMSE. Spirometric recordings were compared to the American Thoracic Society 1994 criteria. RESULTS: FVC was achieved by 51% of patients. Inability to perform FVC was predicted by an MMSE < 24 (specificity 94%, sensitivity of 51%). An FEV1/FEV3 ratio < 80% matched a FEV1/FVC ratio < 70% (sensitivity 96%, specificity 97%). Twenty-five percent of subjects were able to reach FEV3 but not FVC; 14% of that group had an MMSE < 24. Subjects with an MMSE < 20 were unable reliably to perform any spirometry. CONCLUSION: Patients with an MMSE < 24 are usually unable to reach FVC reliably when tested on a single occasion, but some can reach FEV3. Patients with MMSE < 20 cannot do spirometry. An FEV1/FEV3 ratio < 80% can be used to help identify patients with airflow obstruction if they are unable to perform full spirometry to FVC.