Cell type specific roles of FOXP1 during early neocortical murine development.

Cortical development is a tightly controlled process and any deviation during development may increase the susceptibility to neurodevelopmental disorders, such as autism spectrum disorders (ASD). Numerous studies identified mutations in FOXP1, a transcription factor enriched in the neocortex, as causal for ASD and FOXP1 syndrome. Our group has shown that Foxp1 deletion in the mouse cortex leads to overall reduced cortex thickness, alterations in cortical lamination, and changes in the relative thickness of cortical layers. However, the developmental and cell type-specific mechanisms underlying these changes remained unclear. This work characterizes the developmental requirement of neocortical Foxp1 at key embryonic and perinatal ages using a conditional knock-out of Foxp1. We find that Foxp1 deletion results in accelerated pseudo-age during early neurogenesis, increased cell cycle exit during late neurogenesis, altered gene expression and chromatin accessibility, and selective migration deficits in a subset of upper-layer neurons. These data explain the postnatal differences observed in cortical layers and relative cortical thickness. We also highlight genes regulated by FOXP1 and their enrichment with high-confidence ASD or synaptic genes. Together, these results underscore a network of neurodevelopmental disorder-related genes that may serve as potential modulatory targets for postnatal modification relevant to ASD and FOXP1 syndrome.

Dissecting the roles of dynamin and clathrin in platelet pinocytosis.

Platelets endocytose many molecules from their environment. However, this process of pinocytosis in platelets is poorly understood. Key endocytic regulators such as dynamin, clathrin, CDC42 and Arf6 are expressed in platelets but their roles in pinocytosis is not known. Stimulated platelets form two subpopulations of pro-aggregatory and procoagulant platelets. The effect of stimulation on pinocytosis is also poorly understood. In this study, washed human platelets were treated with a range of endocytosis inhibitors and stimulated using different activators. The rate of pinocytosis was assessed using pHrodo green, a pH-sensitive 10 kDa dextran. In unstimulated platelets, pHrodo fluorescence increased over time and accumulated as intracellular puncta indicating constituently active pinocytosis. Stimulated platelets (both pro-aggregatory and procoagulant) had an elevated pinocytosis rate compared to unstimulated platelets. Dynamin inhibition blocked pinocytosis in unstimulated, pro-aggregatory and procoagulant platelets indicating that most platelet pinocytosis is dynamin dependent. Although pinocytosis was clathrin-independent in unstimulated and procoagulant populations, clathrin partially contributed to pinocytosis in pro-aggregatory platelets.

Application of the Cellular Thermal Shift Assay (CETSA) to validate drug target engagement in platelets.

Small molecule drugs play a major role in the study of human platelets. Effective action of a drug requires it to bind to one or more targets within the platelet (target engagement). However, although in vitro assays with isolated proteins can be used to determine drug affinity to these targets, additional factors affect target engagement and its consequences in an intact platelet, including plasma membrane permeability, intracellular metabolism or compartmentalization, and level of target expression. Mechanistic interpretation of the effect of drugs on platelet activity requires comprehensive investigation of drug binding in the proper cellular context, i.e. in intact platelets. The Cellular Thermal Shift Assay (CETSA) is a valuable method to investigate target engagement within complex cellular environments. The assay is based on the principle that drug binding to a target protein increases that protein's thermal stability. In this technical report, we describe the application of CETSA to platelets. We highlight CETSA as a quick and informative technique for confirming the direct binding of drugs to platelet protein targets, providing a platform for understanding the mechanism of action of drugs in platelets, and which will be a valuable tool for investigating platelet signaling and function.

Platelets control blood clotting in health and disease. Small molecule drugs are often used to study human platelets. Here, describe how Cellular Thermal Shift Assay (CETSA) can be used in platelets to investigate the binding between these drugs and their targets inside platelets. This technique can be used to increase our understanding of how existing and future drugs work in platelets.

FOXP1 regulates the development of excitatory synaptic inputs onto striatal neurons and induces phenotypic reversal with reinstatement.

Long-range glutamatergic inputs originating from the cortex and thalamus are indispensable for striatal development, providing the foundation for motor and cognitive functions. Despite their significance, transcriptional regulation governing these inputs remains largely unknown. We investigated the role of a transcription factor encoded by a high-risk autism-associated gene, FOXP1, in sculpting glutamatergic inputs onto spiny projection neurons (SPNs) within the striatum. We find a neuron subtype-specific role of FOXP1 in strengthening and maturing glutamatergic inputs onto dopamine receptor 2-expressing SPNs (D2 SPNs). We also find that FOXP1 promotes synaptically driven excitability in these neurons. Using single-nuclei RNA sequencing, we identify candidate genes that mediate these cell-autonomous processes through postnatal FOXP1 function at the post-synapse. Last, we demonstrate that postnatal FOXP1 reinstatement rescues electrophysiological deficits, cell type-specific gene expression changes, and behavioral phenotypes. Together, this study enhances our understanding of striatal circuit development and provides proof of concept for a therapeutic approach for FOXP1 syndrome and other neurodevelopmental disorders.

Identification of diagnostic biomarkers used in the diagnosis of cardiovascular diseases and diabetes mellitus: A systematic review of quantitative studies.

AIMS: To perform a systematic review of studies that sought to identify diagnostic biomarkers for the diagnosis of cardiovascular diseases (CVDs) and diabetes mellitus (DM), which could be used in low- and middle-income countries (LMICs) where there is a lack of diagnostic equipment, treatments and training. MATERIALS AND METHODS: Papers were sourced from six databases: the British Nursing Index, Google Scholar, PubMed, Sage, Science Direct and Scopus. Articles published between January 2002 and January 2023 were systematically reviewed by three reviewers and appropriate search terms and inclusion/exclusion criteria were applied. RESULTS: A total of 18 studies were yielded, as well as 234 diagnostic biomarkers (74 for CVD and 160 for DM). Primary biomarkers for the diagnosis of CVDs included growth differentiation factor 15 and neurogenic locus notch homologue protein 1 (Notch1). For the diagnosis of DM, alpha-2-macroglobulin, C-peptides, isoleucine, glucose, tyrosine, linoleic acid and valine were frequently reported across the included studies. Advanced analytical techniques, such as liquid chromatography mass spectrometry, enzyme-linked immunosorbent assays and vibrational spectroscopy, were also repeatedly reported in the included studies and were utilized in combination with traditional and alternative matrices such as fingernails, hair and saliva. CONCLUSIONS: While advanced analytical techniques are expensive, laboratories in LMICs should carry out a cost-benefit analysis of their use. Alternatively, laboratories may want to explore emerging techniques such as infrared, Fourier transform-infrared and near-infrared spectroscopy, which allow sensitive noninvasive analysis.

Characterization of orofacial features in sclerodermatous chronic graft-versus-host disease.

BACKGROUND: Chronic graft-versus-host disease (cGVHD) is a leading cause of morbidity and mortality following allogeneic hematopoietic cell transplantation (alloHCT). The sclerodermatous form of cGVHD can be particularly debilitating; however, orofacial sclerodermatous involvement remains poorly described. OBJECTIVE: To characterize orofacial features of sclerodermatous cGVHD in a single center cohort of patients who underwent alloHCT. STUDY DESIGN: Retrospective data were collected from electronic medical records and analyzed descriptively. RESULTS: There were 39 patients who received alloHCT between 1993 and 2017 and developed orofacial sclerodermatous cGVHD. Concomitant cutaneous sclerodermatous cGVHD was common (n = 20, 51%). Orofacial sclerodermatous cGVHD features included fibrous bands of the buccal mucosa (n = 23, 59%), limited mouth opening (n = 19, 54%), perioral fibrosis (n = 8, 21%), and focal gingival recession (n = 4, 10%). Oral mucosal fibrosis was observed at the site of active or resolved chronic lichenoid inflammation in 30 patients, with all but two also presenting with a history of ulcerations. Management included jaw stretching exercises (n = 10; 6 stable/improved), surgery (n = 3; 2 improved), and intralesional corticosteroid injections (n = 2; 2 improved). CONCLUSIONS: Orofacial involvement with sclerodermatous cGVHD can present with multiple manifestations including fibrous banding, limited mouth opening, perioral fibrosis, and focal gingival recession. Surgical and non-surgical management strategies may improve clinical function and reduce morbidity.

Enhanced attention in rats following blast-induced traumatic brain injury.

Purpose: To evaluate visuo-cognitive sequelae following blast-induced traumatic brain injury in a rat model. Methods: Rats were randomly assigned to one of four groups depending on the intensity/quantity of a blast received in a blast chamber: sham (no blast), low intensity (22 psi), medium intensity (26 psi), or three medium intensity blasts (26 psi × 3). After recovery, all subjects were given visual discrimination tasks of increasing complexity, until mastery. After behavioral training, visual function was assessed via spectral-domain optical coherence tomography and pattern electroretinogram, and the extent of retinal damage was quantified via immunohistochemistry of retinal ganglion cells. Results: None of the measures assessing visual function revealed significant differences as a function of blast intensity/quantity. Behavioral training did not disclose short-term effects of blast in general motivation or the development of anticipatory responding. No differences in general learning ability and the number of perseverative errors were observed. However, behavioral training found effects of blast in attentional function; relative to controls, subjects that received blasts were faster in learning to attend to informative (over non-informative) cues in the most difficult visual discrimination task. Conclusion: Blast exposure in rats resulted in increased attention following blast, with no appreciable deficits in visual function. These results are contrary to what is often reported for human clinical populations; as such, more research bridging methodological differences is necessary.

Increasing the number and intensity of shock tube generated blast waves leads to earlier retinal ganglion cell dysfunction and regional cell death.

The purpose of this study was to examine the effect of a blast exposure generated from a shock tube on retinal ganglion cell (RGC) function and structure. Mice were exposed to one of three blast conditions using a shock tube; a single blast wave of 20 PSI, a single blast wave of 30 PSI, or three blast waves of 30 PSI given on three consecutive days with a one-day inter-blast interval. The structure and function of the retina were analyzed using the pattern electroretinogram (PERG), the optomotor reflex (OMR), and optical coherence tomography (OCT). The in vivo parameters were examined at baseline, and then again 1-week, 4-weeks, and 16-weeks following blast exposure. The number of surviving RGCs was quantified at the end of the study. Analysis of mice receiving a 20 PSI injury showed decreased PERG and OMR responses 16-weeks post blast, without evidence of changed retinal thickness or RGC death. Mice subjected to a 30 PSI injury showed decreased PERG responses 4 weeks and 16 weeks after injury, without changes in the retinal thickness or RGC density. Mice subjected to 30 PSI X 3 blast exposures had PERG deficits 1-week and 4-weeks post exposure. There was also significant change in retinal thickness 1-week and 16-weeks post blast exposure. Mice receiving 30 PSI X 3 blast injuries had regional loss of RGCs in the central retina, but not in the mid-peripheral or peripheral retina. Overall, this study has shown that increasing the number of blast exposures and the intensity leads to earlier functional loss of RGCs. We have also shown regional RGC loss only when using the highest blast intensity and number of blast injuries.

Utilizing orthodontic appliances to retain and disguise a pediatric maxillary obturator throughout growth.

Unique challenges are encountered when providing an obturator for an adolescent patient. Challenges include the need to modify the obturator throughout growth, engaging the mixed dentition or partially erupted teeth with minimal undercuts, the psychosocial challenges of an actively maturing patient, and the possible need for coincidental orthodontic therapy. This clinical report describes the ongoing rehabilitation of a patient who presented at the age of 10 with a biopsy-confirmed palatal mucoepidermoid carcinoma. Incorporating orthodontic brackets for retention of innovative adjustable obturator clasps allowed for the favorable function of the obturator prosthesis and the ability to alter the prosthesis over time.

Illustrated Abstracts of the 5th EUPLAN International Conference.

These illustrated capsules have been prepared by some speakers of State-of-the-Art talks and of original investigations, presented at the 5th European Platelet Network (EUPLAN) International Conference, which was held at the Università degli Studi di Milano (Italy) on September 28-30, 2022. The programme featured various state-of-the-art lectures and a selection of oral presentations covering a broad range of topics in platelet and megakaryocyte biology, from basic science to recent advances in clinical studies. As usual, the meeting brought together senior scientists and trainees in an informal atmosphere to discuss platelet science in person.

Platelet-Derived Extracellular Vesicles in Arterial Thrombosis.

Blood platelets are necessary for normal haemostasis but also form life-threatening arterial thrombi when atherosclerotic plaques rupture. Activated platelets release many extracellular vesicles during thrombosis. Phosphatidylserine-exposing microparticles promote coagulation. Small exosomes released during granule secretion deliver cargoes including microRNAs to cells throughout the cardiovascular system. Here, we discuss the mechanisms by which platelets release these extracellular vesicles, together with the possibility of inhibiting this release as an antithrombotic strategy.

Human soluble CD39 displays substrate inhibition in a substrate-specific manner.

CD39 (ectonucleoside triphosphate diphosphohydrolase-1; ENTPD1) metabolizes extracellular ATP and ADP to AMP. AMP is subsequently metabolized by CD79 to adenosine. CD39 activity is therefore a key regulator of purinergic signalling in cancer, thrombosis, and autoimmune diseases. In this study we demonstrate that soluble, recombinant CD39 shows substrate inhibition with ADP or ATP as the substrate. Although CD39 activity initially increased with increasing substrate concentration, at high concentrations of ATP or ADP, CD39 activity was markedly reduced. Although the reaction product, AMP, inhibits CD39 activity, insufficient AMP was generated under our conditions to account for the substrate inhibition seen. In contrast, inhibition was not seen with UDP or UTP as substrates. 2-methylthio-ADP also showed no substrate inhibition, indicating the nucleotide base is an important determinant of substrate inhibition. Molecular dynamics simulations revealed that ADP can undergo conformational rearrangements within the CD39 active site that were not seen with UDP or 2-methylthio-ADP. Appreciating the existence of substrate inhibition of CD39 will help the interpretation of studies of CD39 activity, including investigations into drugs that modulate CD39 activity.

Accuracy of Digital Impressions at Varying Implant Depths: An In Vitro Study.

PURPOSE: Implants placed at variable depths may vary the amount of visible scannable surface of a scan body. Intraoral scanner technology uses advanced optical principles to record the surface of the scan body to accurately capture the implant position. The purpose of this study is to investigate the effect implant placement depth has on the accuracy of digital implant impressions using an intraoral scanner. MATERIALS AND METHODS: A partially edentulous gypsum master model was fabricated to allow the positioning of a single implant analog at different depths. Four groups were created based on the planned implant depths of 7, 6, 3, and 0 mm and corresponding visibility of the scan body at 2, 3, 6, and 9 mm. The model was digitized with a laboratory scanner for the reference scan and with an intraoral scanner to generate 15 test scans per group, with a total of 60 scans. The test scans were superimposed onto the reference scan using the best fit algorithm to analyze and measure the positional (dXYZ) and angular deviation (d⍬) of the scan body using three-dimensional metrology software. Statistical analysis was performed using a one-way ANOVA and pairwise comparison was done with a Tukey-Kramer HSD test (α = 0.05). RESULTS: The one-way ANOVA of the groups for the dXYZ and dθ parameters was statistically significant (F3,56 = 11.45, p < 0.001, F3,56 = 24.04, p < 0.001). Group D (9 mm) showed the least positional deviation at 38.41 µm (95% CI 30.26; 46.56) and the least angular deviation of 0.17° (95% CI 0.12; 0.21). Group A (2 mm) showed the greatest positional deviation of 77.17 µm (95% CI 65.23; 89.11) and greatest angular deviation of 0.84° (95% CI 0.65; 1.03). The positional and angular deviation increased with increased implant depth. CONCLUSIONS: The accuracy of digital impressions is influenced by the implant depth and the amount of visibility of the scan body. The trueness and precision are highest when the implant is placed at 0 mm depth with complete visibility of the scan body and decreases with subgingival implant placement.

Pilot Collection and Evaluation of Head Kinematics in Stock Car Racing.

The goal of this work was to collect on-track driver head kinematics using instrumented mouthpieces and characterize environmental exposure to accelerations and vibrations. Six NASCAR drivers were instrumented with custom-fit mouthpieces to collect head kinematic data. Devices were deployed at four tracks during practice and testing environments and configured to collect approximately 11 min of linear acceleration and rotational velocity data at 200 Hz. This continuous data collection, combined with film review, allowed extraction of complete laps of data. In addition to typical data processing methods, a moving-point average was calculated and subtracted from the overall signal for both linear acceleration and rotational velocity to determine the environmental component of head motion. The current analysis focuses on 42 full laps of data collected at four data collection events. The number of laps per track ranged from 2 to 23. Linear acceleration magnitudes for all 42 laps ranged from 2.46 to 7.48 g and rotational velocity ranged from 1.25 to 3.35 rad/s. After subtracting the moving average, linear acceleration ranged from 0.92 to 5.45 g and rotational velocity ranged from 0.57 to 2.05 rad/s. This study has established the feasibility of using an instrumented mouthpiece to measure head kinematics in NASCAR and presented a technique for isolating head motion due to cornering acceleration from those due to short-term perturbations experienced by the driver.

Patterns of chemotherapy use in muscle-invasive bladder cancer in a tertiary centre.

Objectives: Although neoadjuvant chemotherapy (NAC) has been demonstrated to have significant benefits to survival in patients with muscle-invasive bladder cancer (MIBC), the current utilization of NAC in Australia is unknown. The aim of this study was to evaluate the patterns of neoadjuvant and adjuvant chemotherapy (AC) use in patients undergoing cystectomy for MIBC at a large tertiary institution in Australia. Methods: A retrospective study was conducted using data of patients who underwent a radical cystectomy (RC) at a high-volume centre for MIBC between 2011 and 2021. Results: Of 69 patients who had a cystectomy for ≥ pT2 bladder cancer, 73.9% were eligible for NAC. However, of those eligible, only five patients received NAC (9.8%). Of the total patients who were eligible for AC, only 44.4% received postoperative chemotherapy. Common reasons for the lack of uptake were due to patients being unfit or declining treatment. There was no difference in progression-free survival or overall survival in those who received NAC and AC. Conclusions: The majority of patients undergoing RC for MIBC received AC compared to NAC, reflecting the real-world challenge of NAC uptake. This highlights the need for ongoing improvements in selection and usage of NAC and less reliance of AC utilization post RC.

Immune responses in mice after blast-mediated traumatic brain injury TBI autonomously contribute to retinal ganglion cell dysfunction and death.

PURPOSE: The purpose of this study was to examine the role of the immune system and its influence on chronic retinal ganglion cell (RGC) dysfunction following blast-mediated traumatic brain injury (bTBI). METHODS: C57BL/6J and B6.129S7-Rag1tm1Mom/J (Rag-/-) mice were exposed to one blast injury of 140 kPa. A separate cohort of C57BL/6J mice was exposed to sham-blast. Four weeks following bTBI mice were euthanized, and splenocytes were collected. Adoptive transfer (AT) of splenocytes into naïve C57BL/6J recipient mice was accomplished via tail vein injection. Three groups of mice were analyzed: those receiving AT of splenocytes from C57BL/6J mice exposed to blast (AT-TBI), those receiving AT of splenocytes from C57BL/6J mice exposed to sham (AT-Sham), and those receiving AT of splenocytes from Rag-/- mice exposed to blast (AT-Rag-/-). The visual function of recipient mice was analyzed with the pattern electroretinogram (PERG), and the optomotor response (OMR). The structure of the retina was evaluated using optical coherence tomography (OCT), and histologically using BRN3A-antibody staining. RESULTS: Analysis of the PERG showed a decreased amplitude two months post-AT that persisted for the duration of the study in AT-TBI mice. We also observed a significant decrease in the retinal thickness of AT-TBI mice two months post-AT compared to sham, but not at four or six months post-AT. The OMR response was significantly decreased in AT-TBI mice 5- and 6-months post-AT. BRN3A staining showed a loss of RGCs in AT-TBI and AT-Rag-/- mice. CONCLUSION: These results suggest that the immune system contributes to chronic RGC dysfunction following bTBI.

Representation: raising awareness of opportunities and skill development with undergraduate dental students.

Representatives for dentists are required for many governing committees, local and national, that contribute to many aspects of the profession related to politics, the workplace, education, or community-building. Developing skills as a representative can begin as an undergraduate in student representation systems as part of UK university governance structures. At one UK dental institution, there was a plan to explore the learning and skill development of current student representatives, review the training, identify any areas where there were gaps or where they should be strengthened, and consider whether a new training programme could be developed. Training gaps in the representation process and preference for peer mentoring in training were identified as students acknowledged learning 'on the job' through observation of experienced peers. Current representation training also fell short of highlighting the relevance to their future dental profession. Staff and students co-designed a bespoke programme of training to help students develop their representation skills, as well as align them to the development of professional skills which were determined to be relevant for their future dental career.

All-Terrain Vehicle-Related Emergency Department Visits: Interaction of Sex and Age, NEISS, 2019.

BACKGROUND: Epidemiologic patterns of all-terrain vehicle (ATV)-related emergency department (ED) visits by male and female individuals may vary at different ages. To our knowledge, this has not been researched previously. OBJECTIVE: The purpose of this study was to determine the interaction of sex and age differences in their association with ATV-related ED visits. METHODS: Data from the 2019 National Electronic Injury Surveillance System were extracted for ATV-related ED visits, including sex, age, race, location of crash, injured body part, and whether alcohol was involved. Descriptive statistics and logistic regression analyses were conducted. We modeled sex in separate multivariable models, adjusting for the same independent variables. RESULTS: There were an estimated 95,995 (unweighted n = 1999) ATV-related ED visits. There was a significant age-by-sex interaction in the association between ATV-related ED visits vs. other ED injuries, indicating that the effect of age on ATV-related ED visits differed by sex and vice versa. Overall, male individuals were 1.7 times as likely to have an ATV-related ED visit as female individuals. In the stratified analysis for female individuals, odds were substantially greater for girls younger than 18 years (adjusted odds ratio [AOR] 2.33; 95% confidence interval [CI] 1.61-3.69) and women aged 18-35 years (AOR 4.76; 95% CI 3.48-6.51) compared with woman older than 35 years. For men, odds were significant for ages 18-35 years (AOR 2.21; 95% CI 1.72-2.85) compared with men older than 35 years. CONCLUSIONS: As newer ATVs become more powerful and faster, there is a need to know who is at greatest risk for ATV-related ED visits to develop policies and safety measures.

Protease-activated receptor antagonists prevent thrombosis when dual antiplatelet therapy is insufficient in an occlusive thrombosis microfluidic model.

Background: Platelet activation and arterial thrombosis on a ruptured atherosclerotic plaque is a major cause of myocardial infarction. Dual antiplatelet therapy (DAPT), the combination of platelet aggregation inhibitors, aspirin and a P2Y12 antagonist, is used to prevent arterial thrombosis. However, many people continue to have arterial thrombosis and myocardial infarction despite DAPT, indicating that additional therapies are required where DAPT is insufficient. Objectives: To determine whether antagonists of protease-activated receptors (PARs) can prevent occlusive thrombosis under conditions where DAPT is insufficient. Methods: We used human whole blood in a microfluidic model of occlusive thrombosis to compare conditions under which DAPT is effective to those under which DAPT was not. Cangrelor (a P2Y12 antagonist) and aspirin were used to mimic DAPT. We then investigated whether the PAR1 antagonist vorapaxar or the PAR4 antagonist BMS 986120, alone or in combination with DAPT, prevented occlusive thrombosis. Results and Conclusions: A ruptured plaque exposes collagen fibers and is often rich in tissue factor, triggering activation of platelets and coagulation. Occlusive thrombi formed on type I collagen in the presence or absence of tissue factor (TF). However, although DAPT prevented occlusive thrombosis in the absence of TF, DAPT had little effect when TF was also present. Under these conditions, PAR antagonism was also ineffective. However, occlusive thrombosis was prevented by combining DAPT with PAR antagonism. These data demonstrate that PAR antagonists may be a useful addition to DAPT in some patients and further demonstrate the utility of in vitro models of occlusive thrombosis.

Endothelial inflammation and neutrophil transmigration are modulated by extracellular matrix composition in an inflammation-on-a-chip model.

Inflammatory diseases are often characterised by excessive neutrophil infiltration from the blood stream to the site of inflammation, which damages healthy tissue and prevents resolution of inflammation. Development of anti-inflammatory drugs is hindered by lack of in vitro and in vivo models which accurately represent the disease microenvironment. In this study, we used the OrganoPlate to develop a humanized 3D in vitro inflammation-on-a-chip model to recapitulate neutrophil transmigration across the endothelium and subsequent migration through the extracellular matrix (ECM). Human umbilical vein endothelial cells formed confluent vessels against collagen I and geltrex mix, a mix of basement membrane extract and collagen I. TNF-α-stimulation of vessels upregulated inflammatory cytokine expression and promoted neutrophil transmigration. Intriguingly, major differences were found depending on the composition of the ECM. Neutrophils transmigrated in higher number and further in geltrex mix than collagen I, and did not require an N-formyl-methionyl-leucyl-phenylalanine (fMLP) gradient for transmigration. Inhibition of neutrophil proteases inhibited neutrophil transmigration on geltrex mix, but not collagen I. These findings highlight the important role of the ECM in determining cell phenotype and response to inhibitors. Future work could adapt the ECM composition for individual diseases, producing accurate models for drug development.