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

2021 ◽  
Author(s):  
Camille Douillet ◽  
Marc Nicodeme ◽  
Loïc Hermant ◽  
Vanessa Bergeron ◽  
Fabien Guillemot ◽  
...  
Keyword(s):  
High Resolution ◽  
Soft Tissue ◽  
Dynamic Properties ◽  
Unmet Need ◽  
Specific Pattern ◽  
Matrix Remodeling ◽  
Collagen Gels ◽  
Lattice Contraction

Abstract 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 remodeling in 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 established in vitro to 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 investigate in vitro dermal organizations and properties, processes of remodeling in healing, and new treatment opportunities.

scholarly journals Stretchable and Transparent Metal Nanowire Microelectrodes for Simultaneous Electrophysiology and Optogenetics Applications

Photonics ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 220
Author(s):  
Jinbi Tian ◽  
Zexu Lin ◽  
Zhiyuan Chen ◽  
Sofian N. Obaid ◽  
Igor R. Efimov ◽  
...  
Keyword(s):  
High Resolution ◽  
Electrochemical Performance ◽  
Electrochemical Impedance ◽  
Unmet Need ◽  
Cardiac Activity ◽  
Silver Nanowire ◽  
Optical Transparency ◽  
Metal Nanowire

Recently developed optically transparent microelectrode technology provides a promising approach for simultaneous high-resolution electrical and optical biointerfacing with tissues in vivo and in vitro. A critically unmet need is designing high-performance stretchable platforms for conformal biointerfacing with mechanically active organs. Here, we report silver nanowire (Ag NW) stretchable transparent microelectrodes and interconnects that exhibit excellent electrical and electrochemical performance, high optical transparency, superior mechanical robustness and durability by a simple selective-patterning process. The fabrication method allows the direct integration of Ag NW networks on elastomeric substrates. The resulting Ag NW interface exhibits a low sheet resistance (Rsh) of 1.52–4.35 Ω sq−1, an advantageous normalized electrochemical impedance of 3.78–6.04 Ω cm2, a high optical transparency of 61.3–80.5% at 550 nm and a stretchability of 40%. The microelectrode arrays (MEAs) fabricated with this approach exhibit uniform electrochemical performance across all channels. Studies on mice demonstrate that both pristine and stretched Ag NW microelectrodes can achieve high-fidelity electrophysiological monitoring of cardiac activity with/without co-localized optogenetic pacing. Together, these results pave the way for developing stretchable and transparent metal nanowire networks for high-resolution opto-electric biointerfacing with mechanically active organs, such as the heart.

Evaluation of 99mTc-Label led Vitamin K4 as an Agent for Testicular Imaging

1991 ◽  
Vol 30 (01) ◽  
pp. 35-39 ◽  
Author(s):  
H. S. Durak ◽  
M. Kitapgi ◽  
B. E. Caner ◽  
R. Senekowitsch ◽  
M. T. Ercan
Keyword(s):  
Soft Tissue ◽  
Room Temperature ◽  
Normal Subjects ◽  
Left Testis ◽  
Wide Range ◽  
Activity Ratios ◽  
The Right ◽  
Radioactivity Levels

Vitamin K4 was labelled with 99mTc with an efficiency higher than 97%. The compound was stable up to 24 h at room temperature, and its biodistribution in NMRI mice indicated its in vivo stability. Blood radioactivity levels were high over a wide range. 10% of the injected activity remained in blood after 24 h. Excretion was mostly via kidneys. Only the liver and kidneys concentrated appreciable amounts of radioactivity. Testis/soft tissue ratios were 1.4 and 1.57 at 6 and 24 h, respectively. Testis/blood ratios were lower than 1. In vitro studies with mouse blood indicated that 33.9 ±9.6% of the radioactivity was associated with RBCs; it was washed out almost completely with saline. Protein binding was 28.7 ±6.3% as determined by TCA precipitation. Blood clearance of 99mTc-l<4 in normal subjects showed a slow decrease of radioactivity, reaching a plateau after 16 h at 20% of the injected activity. In scintigraphic images in men the testes could be well visualized. The right/left testis ratio was 1.08 ±0.13. Testis/soft tissue and testis/blood activity ratios were highest at 3 h. These ratios were higher than those obtained with pertechnetate at 20 min post injection.99mTc-l<4 appears to be a promising radiopharmaceutical for the scintigraphic visualization of testes.

scholarly journals Engineering nucleosomes for generating diverse chromatin assemblies

2021 ◽  
Author(s):  
Zenita Adhireksan ◽  
Deepti Sharma ◽  
Phoi Leng Lee ◽  
Qiuye Bao ◽  
Sivaraman Padavattan ◽  
...  
Keyword(s):  
Dynamic Properties ◽  
Dna Nanostructures ◽  
Macromolecular Assemblies ◽  
Maximum Resolution ◽  
Different Types ◽  
Chromatin Structural ◽  
Dna Fragment

Abstract Structural characterization of chromatin is challenging due to conformational and compositional heterogeneity in vivo and dynamic properties that limit achievable resolution in vitro. Although the maximum resolution for solving structures of large macromolecular assemblies by electron microscopy has recently undergone profound increases, X-ray crystallographic approaches may still offer advantages for certain systems. One such system is compact chromatin, wherein the crystalline state recapitulates the crowded molecular environment within the nucleus. Here we show that nucleosomal constructs with cohesive-ended DNA can be designed that assemble into different types of circular configurations or continuous fibers extending throughout crystals. We demonstrate the utility of the method for characterizing nucleosome compaction and linker histone binding at near-atomic resolution but also advance its application for tackling further problems in chromatin structural biology and for generating novel types of DNA nanostructures. We provide a library of cohesive-ended DNA fragment expression constructs and a strategy for engineering DNA-based nanomaterials with a seemingly vast potential variety of architectures and histone chemistries.

scholarly journals Polymorphisms in Plasmodium falciparum dihydropteroate synthetase and dihydrofolate reductase genes in Nigerian children with uncomplicated malaria using high-resolution melting technique

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Adeyemi T. Kayode ◽  
Fehintola V. Ajogbasile ◽  
Kazeem Akano ◽  
Jessica N. Uwanibe ◽  
Paul E. Oluniyi ◽  
...  
Keyword(s):  
High Resolution ◽  
Dihydrofolate Reductase ◽  
Uncomplicated Malaria ◽  
High Resolution Melting ◽  
Intermittent Preventive Treatment ◽  
Preventive Treatment ◽  
Triple Mutant ◽  
Seasonal Malaria Chemoprevention

AbstractIn 2005, the Nigerian Federal Ministry of Health revised the treatment policy for uncomplicated malaria with the introduction of artemisinin-based combination therapies (ACTs). This policy change discouraged the use of Sulphadoxine-pyrimethamine (SP) as the second-line treatment of uncomplicated falciparum malaria. However, SP is used as an intermittent preventive treatment of malaria in pregnancy (IPTp) and seasonal malaria chemoprevention (SMC) in children aged 3–59 months. There have been increasing reports of SP resistance especially in the non-pregnant population in Nigeria, thus, the need to continually monitor the efficacy of SP as IPTp and SMC by estimating polymorphisms in dihydropteroate synthetase (dhps) and dihydrofolate reductase (dhfr) genes associated with SP resistance. The high resolution-melting (HRM) assay was used to investigate polymorphisms in codons 51, 59, 108 and 164 of the dhfr gene and codons 437, 540, 581 and 613 of the dhps gene. DNA was extracted from 271 dried bloodspot filter paper samples obtained from children (< 5 years old) with uncomplicated malaria. The dhfr triple mutant I51R59N108, dhps double mutant G437G581 and quadruple dhfr I51R59N108 + dhps G437 mutant haplotypes were observed in 80.8%, 13.7% and 52.8% parasites, respectively. Although the quintuple dhfr I51R59N108 + dhps G437E540 and sextuple dhfr I51R59N108 + dhps G437E540G581 mutant haplotypes linked with in-vivo and in-vitro SP resistance were not detected, constant surveillance of these haplotypes should be done in the country to detect any change in prevalence.

scholarly journals Activation of transmembrane receptor tyrosine kinase DDR1-STAT3 cascade by extracellular matrix remodeling promotes liver metastatic colonization in uveal melanoma

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Wei Dai ◽  
Shenglan Liu ◽  
Shubo Wang ◽  
Li Zhao ◽  
Xiao Yang ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Cancer Cells ◽  
Uveal Melanoma ◽  
Specific Inhibitor ◽  
Type I ◽  
Matrix Remodeling ◽  
Metastatic Colonization ◽  
Tgf Β1

AbstractColonization is believed a rate-limiting step of metastasis cascade. However, its underlying mechanism is not well understood. Uveal melanoma (UM), which is featured with single organ liver metastasis, may provide a simplified model for realizing the complicated colonization process. Because DDR1 was identified to be overexpressed in UM cell lines and specimens, and abundant pathological deposition of extracellular matrix collagen, a type of DDR1 ligand, was noted in the microenvironment of liver in metastatic patients with UM, we postulated the hypothesis that DDR1 and its ligand might ignite the interaction between UM cells and their surrounding niche of liver thereby conferring strengthened survival, proliferation, stemness and eventually promoting metastatic colonization in liver. We tested this hypothesis and found that DDR1 promoted these malignant cellular phenotypes and facilitated metastatic colonization of UM in liver. Mechanistically, UM cells secreted TGF-β1 which induced quiescent hepatic stellate cells (qHSCs) into activated HSCs (aHSCs) which secreted collagen type I. Such a remodeling of extracellular matrix, in turn, activated DDR1, strengthening survival through upregulating STAT3-dependent Mcl-1 expression, enhancing stemness via upregulating STAT3-dependent SOX2, and promoting clonogenicity in cancer cells. Targeting DDR1 by using 7rh, a specific inhibitor, repressed proliferation and survival in vitro and in vivo outgrowth. More importantly, targeting cancer cells by pharmacological inactivation of DDR1 or targeting microenvironmental TGF-β1-collagen I loop exhibited a prominent anti-metastasis effect in mice. In conclusion, targeting DDR1 signaling and TGF-β signaling may be a novel approach to diminish hepatic metastasis in UM.

scholarly journals Filopodyan: An open-source pipeline for the analysis of filopodia

2017 ◽  
Vol 216 (10) ◽  
pp. 3405-3422 ◽  
Author(s):  
Vasja Urbančič ◽  
Richard Butler ◽  
Benjamin Richier ◽  
Manuel Peter ◽  
Julia Mason ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Dynamic Properties ◽  
Cell Types ◽  
Molecular Heterogeneity ◽  
Interactive Editing ◽  
Motile Cells ◽  
Different Cell Types ◽  
Neuronal Growth Cones

Filopodia have important sensory and mechanical roles in motile cells. The recruitment of actin regulators, such as ENA/VASP proteins, to sites of protrusion underlies diverse molecular mechanisms of filopodia formation and extension. We developed Filopodyan (filopodia dynamics analysis) in Fiji and R to measure fluorescence in filopodia and at their tips and bases concurrently with their morphological and dynamic properties. Filopodyan supports high-throughput phenotype characterization as well as detailed interactive editing of filopodia reconstructions through an intuitive graphical user interface. Our highly customizable pipeline is widely applicable, capable of detecting filopodia in four different cell types in vitro and in vivo. We use Filopodyan to quantify the recruitment of ENA and VASP preceding filopodia formation in neuronal growth cones, and uncover a molecular heterogeneity whereby different filopodia display markedly different responses to changes in the accumulation of ENA and VASP fluorescence in their tips over time.

scholarly journals Pancreatic tumor cell metastasis is restricted by MT1-MMP binding protein MTCBP-1

2018 ◽  
Vol 218 (1) ◽  
pp. 317-332 ◽  
Author(s):  
Li Qiang ◽  
Hong Cao ◽  
Jing Chen ◽  
Shaun G. Weller ◽  
Eugene W. Krueger ◽  
...  
Keyword(s):  
Tumor Cells ◽  
Pancreatic Tumor ◽  
Binding Protein ◽  
Critical Role ◽  
Inverse Correlation ◽  
Pancreatic Tumors ◽  
Matrix Remodeling ◽  
Peripheral Tissues

The process by which tumor cells mechanically invade through surrounding stroma into peripheral tissues is an essential component of metastatic dissemination. The directed recruitment of the metalloproteinase MT1-MMP to invadopodia plays a critical role in this invasive process. Here, we provide mechanistic insight into MT1-MMP cytoplasmic tail binding protein 1 (MTCBP-1) with respect to invadopodia formation, matrix remodeling, and invasion by pancreatic tumor cells. MTCBP-1 localizes to invadopodia and interacts with MT1-MMP. We find that this interaction displaces MT1-MMP from invadopodia, thereby attenuating their number and function and reducing the capacity of tumor cells to degrade matrix. Further, we observe an inverse correlation between MTCBP-1 and MT1-MMP expression both in cultured cell lines and human pancreatic tumors. Consistently, MTCBP-1–expressing cells show decreased ability to invade in vitro and metastasize in vivo. These findings implicate MTCBP-1 as an inhibitor of the metastatic process.

scholarly journals The selective binding and transmigration of monocytes through the junctional complexes of human endothelium.

1988 ◽  
Vol 168 (5) ◽  
pp. 1865-1882 ◽  
Author(s):  
N A Pawlowski ◽  
G Kaplan ◽  
E Abraham ◽  
Z A Cohn
Keyword(s):  
Silver Staining ◽  
Umbilical Vein ◽  
Collagen Gel ◽  
Collagen Gels ◽  
Silver Stain ◽  
Term Survival ◽  
Topographical Distribution ◽  
Junctional Complexes

Human monocytes show a high affinity for vascular endothelium both in vitro and in vivo. To explore monocyte-endothelial interaction in greater detail, we have developed a new in vitro model for growth of human endothelial cells (EC). Human umbilical vein EC (HUVEC) cultured upon collagen gels form confluent monolayers of EC that bind silver at their intercellular border similar to cells in situ. Intercellular junctional structures, both adherens and tight junctions, were identified. In contrast, HUVEC grown on plastic surfaces did not stain with silver. The silver-staining characteristic of EC-collagen monolayers was reversible and related to their in vitro maturation and senescence. Silver staining of EC borders provided a grid by which the location of monocyte binding to the luminal surface of individual EC could be assessed. Using this technique, we found that monocytes preferentially bound to the margins of EC, in approximation to the silver-staining junctions. These results suggest that EC determinants recognized by monocytes occur in a unique topographical distribution on the apical face of EC. After binding, monocytes migrated through the EC monolayers at high basal rates. The lack of penetration of collagen gels in the absence of an EC monolayer suggested the generation of EC-specific chemotactic signal(s). Monocytes were observed to pass between EC without evidence of disruption of the monolayer. Silver stain remained present during all phases of migration, and under transmission electron microscopy, junctional complexes were found proximal to monocytes that had just completed their passage through the monolayer. After orientation to the basal surface of the EC monolayer, monocytes migrated randomly into the underlying collagen gel. Monocyte adherence, penetration, migration, and long term survival can be studied under these conditions.

scholarly journals Continuous Delivery of Stromal Cell-Derived Factor-1 from Alginate Scaffolds Accelerates Wound Healing

2010 ◽  
Vol 19 (4) ◽  
pp. 399-408 ◽  
Author(s):  
Sina Y. Rabbany ◽  
Joseph Pastore ◽  
Masaya Yamamoto ◽  
Tim Miller ◽  
Shahin Rafii ◽  
...  
Keyword(s):  
Wound Healing ◽  
Stromal Cell ◽  
Wound Closure ◽  
Tissue Injury ◽  
Unmet Need ◽  
Novel Therapy ◽  
Yorkshire Pigs ◽  
Stromal Cell Derived Factor

Proper wound diagnosis and management is an increasingly important clinical challenge and is a large and growing unmet need. Pressure ulcers, hard-to-heal wounds, and problematic surgical incisions are emerging at increasing frequencies. At present, the wound-healing industry is experiencing a paradigm shift towards innovative treatments that exploit nanotechnology, biomaterials, and biologics. Our study utilized an alginate hydrogel patch to deliver stromal cell-derived factor-1 (SDF-1), a naturally occurring chemokine that is rapidly overexpressed in response to tissue injury, to assess the potential effects SDF-1 therapy on wound closure rates and scar formation. Alginate patches were loaded with either purified recombinant human SDF-1 protein or plasmid expressing SDF-1 and the kinetics of SDF-1 release were measured both in vitro and in vivo in mice. Our studies demonstrate that although SDF-1 plasmid- and protein-loaded patches were able to release therapeutic product over hours to days, SDF-1 protein was released faster (in vivo Kd 0.55 days) than SDF-1 plasmid (in vivo Kd 3.67 days). We hypothesized that chronic SDF-1 delivery would be more effective in accelerating the rate of dermal wound closure in Yorkshire pigs with acute surgical wounds, a model that closely mimics human wound healing. Wounds treated with SDF-1 protein ( n = 10) and plasmid ( n = 6) loaded patches healed faster than sham ( n = 4) or control ( n = 4). At day 9, SDF-1-treated wounds significantly accelerated wound closure (55.0 ± 14.3% healed) compared to nontreated controls (8.2 ± 6.0%, p < 0.05). Furthermore, 38% of SDF-1-treated wounds were fully healed at day 9 (vs. none in controls) with very little evidence of scarring. These data suggest that patch-mediated SDF-1 delivery may ultimately provide a novel therapy for accelerating healing and reducing scarring in clinical wounds.

scholarly journals Quinolones for the Treatment ofNeisseria GonorrhoeaeandChlamydia Trachomatis

1993 ◽  
Vol 1 (2) ◽  
pp. 108-113 ◽  
Author(s):  
Sebastian Faro
Keyword(s):  
Urinary Tract ◽  
Soft Tissue ◽  
Chlamydia Trachomatis ◽  
Urinary Tract Infections ◽  
Single Agent ◽  
Moderate Activity ◽  
Sexually Transmitted ◽  
Tract Infections

The most commonly sexually transmitted bacteria areNeisseria gonorrhoeaeandChlamydia trachomatis.The quinolones ofloxacin and ciprofloxacin have been shown to have activity against both of these bacteria in vitro and in vivo. Ofloxacin is particularly well suited for the treatment ofN. gonorrhoeaeandC. trachomatiscervical infection, which can be considered the earliest manifestation of pelvic inflammatory disease (PID). Not only can ofloxacin be effectively used as a single agent, it is also useful in treating urinary tract infections caused by Enterobacteriaceae. Although it has moderate activity against anaerobes in general, ofloxacin does have activity against the anaerobes commonly isolated from female patients with soft tissue pelvic infections. Thus, ofloxacin has the potential for being utilized to treat early salpingitis.

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