A novel in vitro tubular model to recapitulate features of distal airways: The bronchioid.

BACKGROUND: Airflow limitation is the hallmark of obstructive pulmonary diseases, with the distal airways representing a major site of obstruction. Although numerous in vitro models of bronchi already exist, there is currently no culture system for obstructive diseases that reproduces the architecture and function of small airways. Here, we aimed to engineer a model of distal airways to overcome the limitations of current culture systems. METHODS: We developed a so-called bronchioid model by encapsulating human bronchial adult stem cells derived from clinical samples in a tubular scaffold made of alginate gel. RESULTS: This template drives the spontaneous self-organisation of epithelial cells into a tubular structure. Fine control of the level of contraction is required to establish a model of the bronchiole, which has a physiologically relevant shape and size. 3D imaging, gene expression and single-cell RNA-seq analysis of bronchioids made of bronchial epithelial cells revealed tubular organisation, epithelial junction formation and differentiation into ciliated and goblet cells. Ciliary beating is observed, at a decreased frequency in bronchioids made of cells from COPD patients. The bronchioid can be infected by rhinovirus. An air-liquid interface is introduced that modulates gene expression. CONCLUSION: Here, we provide a proof of concept of a perfusable bronchioid with proper mucociliary and contractile functions. The key advantages of our approach, such as the air‒liquid interface, lumen accessibility, recapitulation of pathological features and possible assessment of clinically relevant endpoints, will make our pulmonary organoid-like model a powerful tool for preclinical studies.

STEP-COVID: a pilot study of a prenatal intervention for pregnant women during the COVID-19 pandemic.

The COVID-19 pandemic has been associated with a global increase in psychological distress in pregnant women. This study evaluated the effects of STEP-COVID, a six-session mentalization-based prenatal group program offered online during the COVID-19 pandemic. The 100 participants were allocated to STEP-COVID or to the natural trajectory of prenatal care. Pre- and post-intervention assessments included measures of psychological distress, post-traumatic symptoms and positive affectivity. Perception of change during pregnancy on resilience-promoting factors was also assessed at post-intervention. A significant decrease in psychological distress and post-traumatic symptoms and an increase in positive affectivity were observed in participants in the intervention condition, whereas only post-traumatic symptoms improved in the control condition. Women who participated in STEP-COVID also reported greater changes during pregnancy on resilience-promoting factors than women in the control condition. Results hold promise for buffering the effect of the pandemic on the mental health of pregnant women using brief online interventions. Clinical trial registration: NCT05419167 (15/06/2022).

From local to global matrix organization by fibroblasts: a 4D laser-assisted bioprinting approach.

Fibroblasts and myofibroblasts play a central role in skin homeostasis through dermal organization and maintenance. Nonetheless, the dynamic interactions between (myo)fibroblasts and the extracellular matrix (ECM) remain poorly exploited in skin repair strategies. Indeed, there is still an unmet need for soft tissue models allowing to study the spatial-temporal remodeling properties of (myo)fibroblasts.In vivo, wound healing studies in animals are limited by species specificity.In vitro, most models rely on collagen gels reorganized by randomly distributed fibroblasts. But biofabrication technologies have significantly evolved over the past ten years. High-resolution bioprinting now allows to investigate various cellular micropatterns and the emergent tissue organizations over time. In order to harness the full dynamic properties of cells and active biomaterials, it is essential to consider 'time' as the 4th dimension in soft tissue design. Following this 4D bioprinting approach, we aimed to develop a novel model that could replicate fibroblast dynamic remodelingin vitro. For this purpose, (myo)fibroblasts were patterned on collagen gels with laser-assisted bioprinting (LAB) to study the generated matrix deformations and reorganizations. First, distinct populations, mainly composed of fibroblasts or myofibroblasts, were establishedin vitroto account for the variety of fibroblastic remodeling properties. Then, LAB was used to organize both populations on collagen gels in even isotropic patterns with high resolution, high density and high viability. With maturation, bioprinted patterns of fibroblasts and myofibroblasts reorganized into dispersed or aggregated cells, respectively. Stress-release contraction assays revealed that these phenotype-specific pattern maturations were associated with distinct lattice tension states. The two populations were then patterned in anisotropic rows in order to direct the cell-generated deformations and to orient global matrix remodeling. Only maturation of anisotropic fibroblast patterns, but not myofibroblasts, resulted in collagen anisotropic reorganizations both at tissue-scale, with lattice contraction, and at microscale, with embedded microbead displacements. Following a 4D bioprinting approach, LAB patterning enabled to elicit and orient the dynamic matrix remodeling mechanisms of distinct fibroblastic populations and organizations on collagen. For future studies, this method provides a new versatile tool to investigatein vitrodermal organizations and properties, processes of remodeling in healing, and new treatment opportunities.

UVB-induced DHODH upregulation, which is driven by STAT3, is a promising target for chemoprevention and combination therapy of photocarcinogenesis.

The leading cause of cutaneous squamous cell carcinomas (cSCCs) is exposure to ultraviolet radiation (UV). Unlike most other cancers, the incidence rates of cSCCs are still on the rise and the treatment options currently available are limited. We have recently found that dihydroorotate dehydrogenase (DHODH), which is the rate-limiting enzyme in the de novo pyrimidine synthesis pathway, plays a critical role in UVB-induced energy metabolism reprogramming. Using a multistage model of UVB radiation-induced skin cancer, we show that UVB-induced DHODH upregulation is mainly regulated transcriptionally by STAT3. Our results indicate that chronic inhibition of DHODH by leflunomide (LFN) blocks UVB-induced tumor initiation. Human tumor xenograft studies showed that LFN treatment reduces growth of established tumors when used in combination with a genotoxic agent, 5-fluorouracil (5-FU). Our data suggest that DHODH is a promising target for chemoprevention and combination therapy of UVB-induced cSCCs.

NADPH Oxidase-1 Plays a Key Role in Keratinocyte Responses to UV Radiation and UVB-Induced Skin Carcinogenesis.

The nicotinamide adenine dinucleotide phosphate oxidase (NOX) family enzymes are involved in several physiological functions. However, their roles in keratinocyte responses to UV radiation have not been clearly elucidated. This study shows that, among other NOX family members, UVB irradiation results in a biphasic activation of NOX1 that plays a critical role in defining keratinocyte fate through the modulation of the DNA damage response network. Indeed, suppression of both bursts of UVB-induced NOX1 activation by using a specific peptide inhibitor of NOX1 (InhNOX1) is associated with increased nucleotide excision repair efficiency and reduction of apoptosis, which is finally translated into decreased photocarcinogenesis. On the contrary, when only the second peak of UVB-induced NOX1 activation is blocked, both nucleotide excision repair efficiency and apoptosis are decreased. Our results show that inhibition of NOX1 activation could be a promising target for the prevention and treatment of UVB-induced skin cancer in nucleotide excision repair-proficient and -deficient patients.