3D bioprinting meniscus tissue onboard the International Space Station.

We bioprinted meniscus tissue on the International Space Station (ISS) using the onboard BioFabrication Facility (BFF). The three dimensional (3D) printing bioink, cells, culture media and fixative were delivered to the ISS on NG-18 and SpX-27 vehicles and stored prior to the printing operation. The meniscus tissue was fabricated from ink composed of collagens type I and II, chondroitin sulfate and mesenchymal stem cells.

Tumour-intrinsic endomembrane trafficking by ARF6 shapes an immunosuppressive microenvironment that drives melanomagenesis and response to checkpoint blockade therapy.

Tumour-host immune interactions lead to complex changes in the tumour microenvironment (TME), impacting progression, metastasis and response to therapy. While it is clear that cancer cells can have the capacity to alter immune landscapes, our understanding of this process is incomplete. Herein we show that endocytic trafficking at the plasma membrane, mediated by the small GTPase ARF6, enables melanoma cells to impose an immunosuppressive TME that accelerates tumour development.

ARF6-dependent endocytic trafficking of the Interferon-γ receptor drives adaptive immune resistance in cancer.

Adaptive immune resistance (AIR) is a protective process used by cancer to escape elimination by CD8 T cells. Inhibition of immune checkpoints PD-1 and CTLA-4 specifically target Interferon-gamma (IFNγ)-driven AIR. AIR begins at the plasma membrane where tumor cell-intrinsic cytokine signaling is initiated.

Elephant TP53-RETROGENE 9 induces transcription-independent apoptosis at the mitochondria.

Approximately 20 TP53 retrogenes exist in the African and Asian elephant genomes (Loxodonta Africana, Elephas Maximus) in addition to a conserved TP53 gene that encodes a full-length protein. Elephant TP53-RETROGENE 9 (TP53-R9) encodes a p53 protein (p53-R9) that is truncated in the middle of the canonical DNA binding domain. This C-terminally truncated p53 retrogene protein lacks the nuclear localization signals and oligomerization domain of its full-length counterpart.

Hysteresis in poly-2'-deoxycytidine i-motif folding is impacted by the method of analysis as well as loop and stem lengths.

In DNA, i-motif (iM) folds occur under slightly acidic conditions when sequences rich in 2'-deoxycytidine (dC) nucleotides adopt consecutive dC self base pairs. The pH stability of an iM is defined by the midpoint in the pH transition (pH ) between the folded and unfolded states. Two different experiments to determine pH values via circular dichroism (CD) spectroscopy were performed on poly-dC iMs of length 15, 19, or 23 nucleotides.

The Small GTPase ARF6 Activates PI3K in Melanoma to Induce a Prometastatic State.

Melanoma has an unusual capacity to spread in early-stage disease, prompting aggressive clinical intervention in very thin primary tumors. Despite these proactive efforts, patients with low-risk, low-stage disease can still develop metastasis, indicating the presence of permissive cues for distant spread. Here, we show that constitutive activation of the small GTPase ARF6 (ARF6) is sufficient to accelerate metastasis in mice with BRAF/Cdkn2a melanoma at a similar incidence and severity to loss, a major driver of PI3K activation and melanoma metastasis.

Cardiac Tissue Chips (CTCs) for Modeling Cardiovascular Disease.

Objective: Cardiovascular research and regenerative strategies have been significantly limited by the lack of relevant cell culture models that can recreate complex hemodynamic stresses associated with pressure-volume changes in the heart.

Methods: To address this issue, we designed a biomimetic cardiac tissue chip (CTC) model where encapsulated cardiac cells can be cultured in three-dimensional (3-D) fibres and subjected to hemodynamic loading to mimic pressure-volume changes seen in the left ventricle. These 3-D fibres are suspended within a microfluidic chamber between two posts and integrated within a flow loop.

Hemodynamic Stimulation Using the Biomimetic Cardiac Tissue Model (BCTM) Enhances Maturation of Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes.

Human induced pluripotent stem cell (hiPSC)-derived cardio-myocytes (hiPSC-CMs) hold great promise for cardiovascular disease modeling and regenerative medicine. However, these cells are both structurally and functionally -immature, primarily due to their differentiation into cardiomyocytes occurring under static culture which only reproduces biomolecular cues and ignores the dynamic hemo-dynamic cues that shape early and late heart development during cardiogenesis. To evaluate the effects of hemodynamic stimuli on hiPSC-CM maturation, we used the biomimetic cardiac tissue model to reproduce the hemodynamics and pressure/volume changes associated with heart development.

Mitoquinone ameliorates pressure overload-induced cardiac fibrosis and left ventricular dysfunction in mice.

Increasing evidence indicates that mitochondrial-associated redox signaling contributes to the pathophysiology of heart failure (HF). The mitochondrial-targeted antioxidant, mitoquinone (MitoQ), is capable of modifying mitochondrial signaling and has shown beneficial effects on HF-dependent mitochondrial dysfunction. However, the potential therapeutic impact of MitoQ-based mitochondrial therapies for HF in response to pressure overload is reliant upon demonstration of improved cardiac contractile function and suppression of deleterious cardiac remodeling.

Growing Human Parathyroids in a Microphysiological System: A Novel Approach to Understanding and Developing New Treatments for Hyperparathyroidism.

We developed a novel model for studying hyperparathyroidism by growing ex vivo 3-dimensional human parathyroids as part of a microphysiological system (MPS) that mimics human physiology. The purpose of this study was to validate the parathyroid portion of the MPS. We prospectively collected parathyroid tissue from 46 patients with hyperparathyroidism for growth into pseudoglands.

Rapid Screen of Potential i-Motif Forming Sequences in DNA Repair Gene Promoters.

We have studied the in vitro stability of 25 potential i-motif-forming DNA sequences found within the promoter regions of 18 different human DNA repair genes. Three widely available methods of characterization were used to rapidly assess i-motif folding and stability and comprise a simple screen for preliminary identification of physiologically relevant i-motif forming sequences. Four highly pH-stable candidate sequences were identified exhibiting pH transitions (pH at which 50% of the oligodeoxynucleotides in solution are folded) at or above pH 6.

Unusual Isothermal Hysteresis in DNA i-Motif pH Transitions: A Study of the RAD17 Promoter Sequence.

We have interrogated the isothermal folding behavior of the DNA i-motif of the human telomere, dC, and a high-stability i-motif-forming sequence in the promoter of the human DNA repair gene RAD17 using human physiological solution and temperature conditions. We developed a circular-dichroism-spectroscopy-based pH titration method that is followed by analysis of titration curves in the derivative domain and found that the observed pH-dependent folding behavior can be significantly different and, in some cases, multiphasic, with a dependence on how rapidly i-motif folding is induced. Interestingly, the human telomere sequence exhibits unusual isothermal hysteresis in which the unfolding process always occurs at a higher pH than the folding process.

Review: Microfluidics technologies for blood-based cancer liquid biopsies.

Blood-based liquid biopsies provide a minimally invasive alternative to identify cellular and molecular signatures that can be used as biomarkers to detect early-stage cancer, predict disease progression, longitudinally monitor response to chemotherapeutic drugs, and provide personalized treatment options. Specific targets in blood that can be used for detailed molecular analysis to develop highly specific and sensitive biomarkers include circulating tumor cells (CTCs), exosomes shed from tumor cells, cell-free circulating tumor DNA (cfDNA), and circulating RNA. Given the low abundance of CTCs and other tumor-derived products in blood, clinical evaluation of liquid biopsies is extremely challenging.

4n-1 Is a "Sweet Spot" in DNA i-Motif Folding of 2'-Deoxycytidine Homopolymers.

Strands of DNA with four or more contiguous runs of 2'-deoxycytidine (dC) nucleotides have the potential to adopt i-motif folds, generally under mildly acidic conditions. Analysis of dC homo-oligonucleotide strands ranging in length from 10 to 30 nucleotides by five different pH-dependent methods identified a pattern in strand length vs stability. Beginning with dC, which does not fold, the transition pH (pH) increased with chain length with the addition of up to four nucleotides, after which the stability dramatically decreased, and the trend repeated this cycle up to dC.

Biomimetic Cardiac Tissue Model Enables the Adaption of Human Induced Pluripotent Stem Cell Cardiomyocytes to Physiological Hemodynamic Loads.

Induced pluripotent stem cell derived cardiomyocytes (iPSC-CMs) provide a human source of cardiomyocytes for use in cardiovascular research and regenerative medicine. However, attempts to use these cells in vivo have resulted in drastic cell death caused by mechanical, metabolic, and/or exogenous factors. To explore this issue, we designed a Biomimetic Cardiac Tissue Model (BCTM) where various parameters associated with heart function including heart rate, peak-systolic pressure, end-diastolic pressure and volume, end-systolic pressure and volume, and ratio of systole to diastole can all be precisely manipulated to apply hemodynamic loading to culture cells.

ARF6 Is an Actionable Node that Orchestrates Oncogenic GNAQ Signaling in Uveal Melanoma.

Activating mutations in Gαq proteins, which form the α subunit of certain heterotrimeric G proteins, drive uveal melanoma oncogenesis by triggering multiple downstream signaling pathways, including PLC/PKC, Rho/Rac, and YAP. Here we show that the small GTPase ARF6 acts as a proximal node of oncogenic Gαq signaling to induce all of these downstream pathways as well as β-catenin signaling. ARF6 activates these diverse pathways through a common mechanism: the trafficking of GNAQ and β-catenin from the plasma membrane to cytoplasmic vesicles and the nucleus, respectively.

Pre-filled syringes: a review of the history, manufacturing and challenges.

Pre-filled syringes are convenient devices for the delivery of parenteral medications. They are small which makes them easy to carry and are dependable for delivering a precise dose of medication. These and many other reasons are leading to their growth in the pharmaceutical market.

Hyperglycemic arterial disturbed flow niche as an in vitro model of atherosclerosis.

Type 2 diabetes significantly elevates the risk of cardiovascular disease. This can be largely attributed to the adverse effects of hyperglycemic conditions on normal endothelial cell (EC) function. ECs in both large and small vessels are influenced by hyperglycemic conditions, which increase susceptibility to EC dysfunction and atherosclerotic lesion formation.

The small GTPase ARF6 stimulates β-catenin transcriptional activity during WNT5A-mediated melanoma invasion and metastasis.

β-Catenin has a dual function in cells: fortifying cadherin-based adhesion at the plasma membrane and activating transcription in the nucleus. We found that in melanoma cells, WNT5A stimulated the disruption of N-cadherin and β-catenin complexes by activating the guanosine triphosphatase adenosine diphosphate ribosylation factor 6 (ARF6). Binding of WNT5A to the Frizzled 4-LRP6 (low-density lipoprotein receptor-related protein 6) receptor complex activated ARF6, which liberated β-catenin from N-cadherin, thus increasing the pool of free β-catenin, enhancing β-catenin-mediated transcription, and stimulating invasion.

Epithelial tight junction alterations in nasal polyposis.

Objective: To explore alterations in expression of tight junction proteins (TJPs) in nasal polyposis and in respiratory epithelium under inflammatory conditions. Our hypothesis is that exposure of nasal and respiratory epithelium to inflammatory cytokines results in the altered expression of specific TJPs.

Methods: Human sinonasal mucosa (3 nasal polyp specimens and 3 nonpolypoid controls) were stained with immunofluorescent markers specific for TJPs claudin-1 and occludin and examined with confocal scanning laser microscopy.

Characterization of the cellular and antitumor effects of MPI-0479605, a small-molecule inhibitor of the mitotic kinase Mps1.

Mps1 is a dual specificity protein kinase that is essential for the bipolar attachment of chromosomes to the mitotic spindle and for maintaining the spindle assembly checkpoint until all chromosomes are properly attached. Mps1 is expressed at high levels during mitosis and is abundantly expressed in cancer cells. Disruption of Mps1 function induces aneuploidy and cell death.

The utility of cadaver dissection in endoscopic sinus surgery training courses.

Background: Understanding paranasal sinus anatomy is crucial for successful outcomes in endoscopic sinus surgery (ESS). This study was designed to evaluate subjective and objective differences in ESS cadaver dissections among participants of varying experience levels in association with the use of image guidance and computer-aided technologies in a physician training cadaver dissection laboratory.

Methods: Participants in a 2-day cadaver dissection course completed daily predissection surveys evaluating subjective comfort with ESS.

Inferior meatus endoscopy and directed treatment for epiphora: early experience with a novel approach.

Objectives: Epiphora results from obstruction along the nasolacrimal (NL) system. The inferior meatus (IM) is not routinely evaluated. IM pathology is common in patients with epiphora, allowing surgery to be directed at the IM.

Contemporary considerations in cranial-base surgery.

The development of new surgical and medical management techniques in skull-base surgery allows for improved patient care. The operative complexities encountered in these procedures necessitate a team-based approach to address total care of the surgical patient. A review of contemporary considerations in management of the patient undergoing skull-base surgery reveals the need for pre- and postoperative planning of surgical and medical management.