Unravelling respiratory microflows in silico and in vitro: novel paths for targeted pulmonary delivery in infants and young children
Fundamental research on respiratory transport phenomena, quantifying momentum and mass transfer in the lung depths, is overwhelmingly focused on adults. Yet, children are not just miniature adults; their distinct lung structures and heterogeneous ventilation patterns set them aside from their parents. In RespMicroFlows, we will break this cycle and unravel the complex microflows characterizing alveolar airflows in the developing pulmonary acini. Our discoveries will foster ground-breaking transport strategies to tackle two urgent clinical needs that burden infants and young children. The first challenge relates to radically enhancing the delivery and deposition of therapeutics using inhalation aerosols; the second involves targeting liquid bolus installations in deep airways for surfactant replacement therapy. By developing advanced in silico numerical simulations together with microfluidic in vitro platforms mimicking the pulmonary acinar environment, our efforts will not only deliver a gateway to reliably assess the outcomes of inhaling aerosols and predict deposition patterns in young populations, we will furthermore unravel the fundamentals of liquid bolus transport to achieve optimal surfactant delivery strategies in premature neonates. By recreating cellular alveolar environments that capture underlying physiological functions, our advanced acinus-on-chips will deliver both at true scale and in real time the first robust and reliable in vitro screening platforms of exogenous therapeutic materials in the context of inhaled aerosols and surfactant-laden installations. Combining advanced engineering-driven flow visualization solutions with strong foundations in transport phenomena, fluid dynamics and respiratory physiology, RespMicroFlows will pave the way to a new and unprecedented level in our understanding and quantitative mapping of respiratory flow phenomena and act as catalyst for novel targeted pulmonary drug delivery strategies in young children.
SOURCE: Starting Grant, European Research Council (ERC, H2020)
Bioengineered microfluidic in vitro testing platforms of alveolar transport and clearance
With the advent of miniaturization and microfabrication techniques, microfluidic lab-on-chips are offering increasingly attractive opportunities to deliver multifunctional in vitro solutions that reproduce structural, functional and physiological properties of human body organs. The outlined research revolves around the development and integration of cutting-edge engineered microfluidic systems mimicking critical physiological functions of the cellular makeup of the deep alveolated lungs, also known as the pulmonary acinus. By reconstituting the human alveolar epithelial barrier in vitro, our pulmonary organ-on-chip analogues will provide an integrative gateway for in vitro analysis of both, transport across the alveolar epithelial barrier towards the blood stream as well as uptake and subsequent clearance by key cellular players of our immune system (i.e. alveolar macrophages). Our interdisciplinary bio-engineering efforts are expected to have significant impact, both for (nano)toxicological studies of inhaled engineered nanomaterials (ENMs) as well as for testing of advanced inhaled aerosol therapeutics, in healthy and diseased state. Not only will our microfluidic platforms recreate physiological breathing movements and their influence on the deposition, absorption and clearance of aerosolized particles, our acini-on-chip will allow quantitative on-line measurements of alveolar barrier function, absorption kinetics and immunologically relevant responses; these undertakings will deliver tangible solutions for parallelization and high-throughput assays. Importantly, our research endeavors are offering perspectives towards viable alternatives to animal testing and as a predictive preclinical model to facilitate translation of advanced aerosol medicines into the clinics.
SOURCE: German-Israeli Foundation for Scientific Research and Development (GIF)
COLLABORATORS: Claus-Michael Lehr (Helmholtz Institute, Saarland Germany)
Dynamic bile flow modelling and cellular sensing in primary sclerosing cholangitis
Primary sclerosing cholangitis (PSC) is a progressive liver disease characterized by fibroobliterative destruction of the intra- and/or extra-hepatic bile ducts, leading to liver cirrhosis and an increased risk of malignancy. There is no effective medical therapy for PSC, and the majority of patients will eventually require liver transplantation. Following a primary immunological insult to the bile duct, biliary flow obstruction leads to pressure damage to the biliary epithelium and drives disease progression. We will use a systems biology approach to model the hydrodynamic and signalling consequences of the altered biliary flow. We will i) experimentally map and model the 3D structure and cellular interactions of small bile ducts in well characterized and long-term followed patients and animal models of PSC, ii) perform 3D geometry-based hydrodynamic modelling, and iii) calibrate models on intravital imaging of biliary flow in murine models, iv) look at the consequences on cellular programing using in-situ functional genomics and v) mechanistically analyse and model biliary pressure sensing and it´s signalling consequences. The resulting spatiotemporal model of altered bile flow and signalling will allow A) to identify targets for the utterly needed pharmacological intervention to prevent pressure-driven biliary damage and B) pave the way for personalized pharmacological biliary pressure optimization in affected patients.
SOURCE: ERACoSysMed (ERA-NET, H2020)
COLLABORATORS: Jochen Hampe (TU Dresden Germany, Coordinator), Tom Hemming Karlsen (Norway), M. Trauner (Austria), M. Zerial (Germany), J. Sznitman (Israel), P. Delmas (France).
Quantifying Locomotion in the Model Organism Caenorhabditis elegans for characterization of Muscular Diseases and Motility Deficiencies
Muscular dystrophy (MD) is a group of inherited disorders characterized by progressive muscle weakness, and ultimately the death of muscle cells and tissue. While some cases progress very slowly over a lifetime, others produce severe muscle weakness, functional disability, and loss of the ability to walk. In particular, severe forms of MD tend to occur during infancy and lead to death at an early age. To this day, there are no known cures for MD. In the quest for treatment, the worm Caenorhabditis elegans is an important model organism for elucidating the genetic basis of MD since the nematode’s entire genetic code is known. A widespread strategy is to classify nematode movements (e.g. swimming speed) and characterize them quantitatively to motility behavior with genes carrying MD. The proposed research aims to develop non-invasive diagnostic tools that characterize not only the nematode’s movement but also the material properties (e.g. stiffness) of its tissues. Our proposed methods will provide an innovative and more robust quantitative analysis of C. elegans carrying genetic mutations associated with MD. Our activities will revolutionize the understanding of C. elegans motility and provide a sensitive, quantitative, and high-throughput platform on which to understand new muscle mutants and advance drug testing. Altogether, this research program will contribute to a better understanding of motility-based diseases such as Muscular Dystrophy.
SOURCE: US-Israel Binational Science Foundation (BSF)
COLLABORATORS: Paulo Arratia (University of Pennsylvania, USA); Todd Lamitina (University of Pittsburgh, USA)
Quantitative mapping of inhaled ultrafine particle transport in pulmonary acinar networks
Inhaled ultrafine nanoparticles have the ability to reach the distal regions of the lung, and deposit on the airways of the pulmonary acinus where alveoli are abundant. Once deposited, these nanoparticles aerosols can bypass the lung’s clearance mechanisms and translocate across the alveolar septa into the systemic circulation, ultimately reaching other organs of our body. Whether inhaled ultrafine particles (UFPs) are recognized as a health risk or a therapeutic tool, their transport properties are expected to depend on the micro airflows present in the alveolar airspace as well as on blood microcirculation in the alveolar microvasculature. Due to the microscale dimensions and limited accessibility, flow characteristics and dynamics of particle transport are challenging to assess directly in the pulmonary acinar region. Hence, inhaled nanoparticle transport still remains widely understood as a process driven by diffusive mechanisms only. Here we aim at elucidating quantitatively the transport properties of UFPs directly at the acinar scale, both in the air- and the blood-phase of the acinus. We will quantify dynamics and kinematics of inhaled nanoparticles using computational fluid dynamics (CFD) and experimental flow velocimetry techniques. For the latter approach, we will design in vitro microfluidic models of acinar networks replicating physiologically- and hydrodynamically-realistic (i) respiratory alveolar airflows and (ii) blood flows of the microvasculature. To bridge UFP transport data in air- and blood-phase models respectively, microfluidic networks will integrate biological functionality to mimic the cellular environment representative of the alveolar-capillary interface. This strategy will help determine spatial-temporal properties of UFP translocation across the air-blood barrier, and deliver an integrative and quantitative roadmap of the complex interactions between particle transport, deposition and translocation processes occurring at the acinar scale. Altogether our efforts serve as a first step towards mapping quantitatively how inhaled UFPs ultimately enter the broader systemic circulation by originating in the acinar pathways.
SOURCE: Israel Science Foundation (ISF)
Role of Mechanosensory Touch-Based Cues in Arborization of Neuronal Dendritic Trees
To convey sensory touch inputs, neurons must have the ability to sense and translate mechanical stimuli into electrical signals. This process, known as mechanosensation, relies on the proper structuring and development of neuronal dendritic trees (arborization). There is growing evidence supporting the required role of environmental cues in determining the definitive morphology of dendritic trees. In turn, arborization is expected to result from both intrinsic neuronal differentiation as well as extrinsic contributions from the external environment. However, there is little understanding of how mechanosensory signals regulate the morphological arborization process, and conversely how the morphology of dendritic trees affects mechanosensation. Yet, defects in neuronal development and mechanosensory function can contribute to neuro-developmental disorders such as Down’s syndrome and autism. In the present proposal, we aim at deepening our quantitative understanding of the influence of touch-based sensory input in determining dendritic patterns during development. The proposed work is built around three pillars of research using the model organism Caenorhabditis elegans. We will implement (i) live imaging techniques of mechanosensory touch neurons in whole organisms, (ii) statistical models using machine learning to quantify the structure and patterns of neuronal trees, and (iii) behavioral assays of C. elegans to characterize the influence of extrinsic sensory inputs on motility phenotypes. This latter step will rely heavily on engineering fluidics and quantitative visualization techniques. It is anticipated that an integral characterization of the coupling between mechanosensory input and dendritic arborization will pave the way towards a better understanding of neurodegenerative diseases and potential treatment strategies.
SOURCE: Marie Skłodowska-Curie actions (FP7, European Commission)
Lung-on-chip alveolar models for inhaled particle cytotoxicity in alveolar epithelial cells
The fate of environmentally- or occupationally-inhaled ultrafine particles (UFPs), with diameters less than 100 nm, is drawing considerable attention due to potential health threats that emanate from human-related industrial activities. UFPs are now known to bypass the lungs’ defense mechanisms and penetrate through the alveolar tissue barrier, ultimately translocating into the systemic blood circulation. Epidemiological studies give evidence that high concentrations of UFPs, formed by gas-to-particle conversion or incomplete fuel combustion, may cause increased pulmonary and cardiovascular morbidity and mortality. Current nanotoxicology approaches to investigate inhaled UFP cytotoxicity in the lungs are still limited and often rely on NP exposure over simple cell cultures. Within the frame of this Pilot Research Grant, we are currently designing a microfluidic-based lab-on-chip model of the alveolated airways of the lungs in an effort to develop an in vitro aerosol exposure system for airborne ultrafine particle (UFP) deposition on alveolar epithelial cells (AECs). Using such microfluidic platform integrated with an aerosol exposure system, we will conduct cytotoxicity assays of inhaled toxic UFPs on alveolar epithelial cells (AECs).
SOURCE: The Environment and Health Fund (EHF), Israel
COLLABORATORS: Barbara Rothen (University of Fribourg, Switzerland); Peter Ertl (TU Wien, Austria)