Page 58 - ASME_NEMB_2016_Program

Technical Program TRACK 4

5:20pm Instability-driven vesicle growth in high membrane ten- 10:00am Tuning inflammation towards regeneration: a new
sion environment strategy in tissue engineering.

Technical Presentation. NEMB2016-6077 Technical Presentation. NEMB2016-6046

Nikhil Walani, Jennifer Torres, Ashutosh Agrawal, University of Francesca Taraballi, Department of NanoMedicine, Houston Meth-
Houston, Houston, TX, United States odist Research Institute, Houston, TX, USA, Houston, TX, United
States, Bruna Corradetti, Department of Life and Environmental
Clathrin-mediated endocytosis (CME) is a key metabolic pathway that plays Sciences, Universita’ Politecnica delle Marche, Ancona, Italy, Clau-
a central role in the delivery of nutrients and drug carriers into cells. In this dia Corbo, Laura Pandolfi, houston Methodist Research Institute,
work, we model the interactions of lipid membranes with different types of Houston, TX, United States, Silvia Minardi, Department of Nano-
protein scaffolds and active forces to provide mechanistic insights into CME.
To this end, we develop and employ an extended theoretical framework Medicine, Houston Methodist Research Institute, Houston, TX, USA,
of lipid membranes that entertains spatial heterogeneity and local anisot- Houston, TX, United States, Fernando Cabrera, Xin Wang, Hous-
ropy that could arise from membrane-protein interactions. We show that a ton Methodist Institute Research, houston, TX, United States, Jeff
departure from homogeneity and isotropy can lead to a variable surface Van Eps, Houston Methodist Research Inst., Houston, TX, United
tension field, conventionally assumed to be a constant parameter. We model States, Sebastian Powell, Houston Methodist Institute Research,
the impact of resting tension in a cell and discuss its consequences on the houston, TX, United States, Bradley Weiner, Houston Methodist
minimal protein machinery needed to complete vesicle formation. Based on Hospital, Houston, TX, United States, Ennio Tasciotti, The Method-
our quantitative model and findings, we highlight the physical principles that ist Hospital Research Institute, Houston, TX, United States
unify CME in apparently distinct yeast and mammalian cells.

The foreign body response can be described as a non-specific immune
response to any implanted foreign materials. It is usually characterized by
WEDNESDAY, FEBRUARY, 24 the massive infiltration of inflammatory cells (including macrophages and T
cells) at the surface of the implant. Physiologically this process aims at the
clearance of the foreign material, and at the regeneration of the damaged
tissue. This inflammatory phase is also elicited by the implantation of any
4-8 tissue engineered scaffold, and it could dramatically result in the failure of
CELLULAR ENGINEERING the implant. Although the foreign body reaction could appear detrimental, it
could be cunningly exploited to trigger and boost the regeneration process
towards functional recovery.
Harris 9:30am - 11:00am
Conventional tissue engineering approaches have been developed to stim-
Session Organizer: Himani Agrawal, University of Houston, Hous- ulate the stem cell niche towards healing. On the contrary, in this study, we
ton, TX, United States focused on the ability to design and develop an immune-instructive scaffold
for tissue engineering, able to tune the fate of inflammatory cells, and to
9:30am Engineering programmable, dynamic materials using achieve faster tissue remodeling. Using a biomimetic approach, we function-
bio-inspired communication alized a porous collagen scaffold with chondroitin sulfate (CSCL), a glycos-
aminoglycan vastly present in the extracellular matrix of different tissues and
known to have anti-inflammatory properties. The efficacy of such function-
Keynote. NEMB2016-5941 alization was assessed firstly in vitro, to elucidate the molecular mechanism
in an in vitro model of inflammation, and then in a rat subcutaneous implant
Cheemeng Tan, UC Davis, Davis, CA, United States model by evaluating the effect of CSCL in tuning the inflammation. We char-
acterized at a molecular, cellular and tissue level (qPCR, flow cytometry and
Dynamic, bio-mimetic materials operate autonomously by sensing and immunofluroescence) the effects of this scaffold at early (1, 3 and 7 days) and
adapting to their surrounding environment. Engineered to respond to a mul- late (21 days) time points in comparison with an unmodified collagen scaf-
titude of extracellular signals (e.g., proteases, pH, light), these materials gen- fold (CL). After 1 day, we found both scaffolds completely infiltrated by cells.
erally react by releasing small molecules into their surroundings. While these We characterized the populations of the infiltrated cells by flow cytometry,
state-of-the-art engineered materials can sense their environment, two-way finding that 95% of the total cells recruited by CSCL were macrophages,
communications, like those prevalent in natural systems, remain difficult due while in CL represented only the 40%. Moreover, the 90% of these cells
to the myriad of interactions inherent in cell-like environments. Here, we was positive for anti-inflammatory associated markers, such as CD206 and
exploit synthetic biology approaches to develop the first modular dynamic IL-10. The same results were achieved with CL only 7 days after the implant.
material that can perform two-way communications with natural cells. The We further investigated by PCR arrays, which molecular pathways was
dynamic material, also called artificial cell, mimics several key properties of activated by such cells, and we confirmed that cells recruited by CSCL ex-
natural cells, including synthetic membranes, molecular transport, gene ex- pressed higher levels of chemokines and cytokines involved in the positive
pression, and cell-cell communication. They are assembled from the bottom regulation of the immune system processes and chemotaxis. This massive
up using lipids, DNA, protein synthesis machineries, NTP, amino acids, and activation was progressively turned off during the analyzed time points and
various accessory proteins and chemicals. We demonstrate cell-cell com- at a faster rate for CSCL, rather than CL. The final outcome of these early
munication under three scenarios: artificial cells signaling bacteria, bacteria events culminated in the differences found between treatment groups after
signaling artificial cells, and artificial cells signaling each other. To guide the 21 days. We demonstrated a marked reduction in the expression of markers
control of the systems, mathematical models are developed to describe associated to chronic inflammation (IL-6) and fibrosis (F13a1, Fga, Plat, and
the genetic circuitry of each system as well as the spatial distribution of the Plaur), together with an overexpression of the markers of vascularization and
transmitters, receivers, and the diffusing signal molecules. We illustrate po- tissue remodeling in CSCL. Finally, through histological evaluation at 21 days,
tential applications of the artificial cells by implementing artificial cells that in- the scaffolds appeared fully integrated within the surrounding tissue, show-
duce the synthesis of an antimicrobial peptide in bacteria. The antimicrobial ing higher and homogenous level of vascularization, as anticipated by the
peptide inhibits bacterial growth, providing a possible alternative strategy for molecular analysis at the earlier time points. Altogether, these data suggest
the treatment of antibiotic-resistant bacteria. The development of communi- that targeting the inflammatory phase induced by implanted biomaterials is
58 cation between artificial cells and living cells provides further insight into cell a promising strategy to accelerate the tissue integration of the scaffold and
communication in general, opens the door for new therapeutic uses of artifi- achieve faster healing of the defect.
cial cells, and expands the capacity of artificial systems to mimic living ones.