Racial inequities and rare CFTR variants: Impact on cystic fibrosis diagnosis and treatment.

Cystic fibrosis (CF) has been traditionally viewed as a disease that affects White individuals. However, CF occurs among all races, ethnicities, and geographic ancestries. The disorder results from mutations in the CF transmembrane conductance regulator (CFTR). Varying incidence of CF is reported among Black, Indigenous, and People of Color (BIPOC), who typically exhibit worse clinical outcomes. These populations are more likely to carry rare CFTR variants omitted from newborn screening panels, leading to disparities in care such as delayed diagnosis and treatment. In this study, we present a case-in-point describing an individual of Gambian descent identified with CF. Patient genotype includes a premature termination codon (PTC) (c.2353C>T) and previously undescribed single nucleotide deletion (c.1970delG), arguing against effectiveness of currently available CFTR modulator-based interventions. Strategies for overcoming these two variants will likely include combinations of PTC suppressors, nonsense mediated decay inhibitors, and/or alternative approaches (e.g. gene therapy). Investigations such as the present study establish a foundation from which therapeutic treatments may be developed. Importantly, c.2353C>T and c.1970delG were not detected in the patient by traditional CFTR screening panels, which include an implicit racial and ethnic diagnostic bias as these tests are comprised of mutations largely observed in people of European ancestry. We suggest that next-generation sequencing of CFTR should be utilized to confirm or exclude a CF diagnosis, in order to equitably serve BIPOC individuals. Additional epidemiologic data, basic science investigations, and translational work are imperative for improving understanding of disease prevalence and progression, CFTR variant frequency, genotype-phenotype correlation, pharmacologic responsiveness, and personalized medicine approaches for patients with African ancestry and other historically understudied geographic lineages.

S.P.O.R.R.T.-A Comprehensive Approach to the Assessment and Non-Operative Management of Overuse Knee Conditions in Youth Athletes.

PURPOSE OF REVIEW: The evaluation of a young athlete with an overuse injury to the knee involves a comprehensive approach. There are a number of elements to consider including assessments of skeletal maturity (biologic maturation), workload (training load + competition load), sport specialization status, and biomechanics. The type of injury and treatment, as well as future prognosis, may be influenced by these and other factors. RECENT FINDINGS: Calculating the percentage of predicted adult height (PPAH) is a valuable tool in assessing overuse injury patterns and diagnoses in youth athletes. Modifiable and non-modifiable overuse injury risk factors require monitoring from clinicians as young athletes mature and develop over time. Training and rehabilitation programs should be adapted to account for these. In this manuscript, we seek to introduce a novel, comprehensive approach: S.P.O.R.R.T. (Skeletal Maturity, Prior Injury Risk, One Sport Specialization, Rehabilitation, Return to Play, Training Recommendations) (Fig. 1). Overuse, non-traumatic injuries to the knee in youth athletes will be presented in a case-based and evidence-based model to provide a framework for a comprehensive approach to the assessment and treatment of youth athletes with overuse injuries.

Mathematical models of cystic fibrosis as a systemic disease.

Cystic fibrosis (CF) is widely known as a disease of the lung, even though it is in truth a systemic disease, whose symptoms typically manifest in gastrointestinal dysfunction first. CF ultimately impairs not only the pancreas and intestine but also the lungs, gonads, liver, kidneys, bones, and the cardiovascular system. It is caused by one of several mutations in the gene of the epithelial ion channel protein CFTR. Intense research and improved antimicrobial treatments during the past eight decades have steadily increased the predicted life expectancy of a person with CF (pwCF) from a few weeks to over 50 years. Moreover, several drugs ameliorating the sequelae of the disease have become available in recent years, and notable treatments of the root cause of the disease have recently generated substantial improvements in health for some but not all pwCF. Yet, numerous fundamental questions remain unanswered. Complicating CF, for instance in the lung, is the fact that the associated insufficient chloride secretion typically perturbs the electrochemical balance across epithelia and, in the airways, leads to the accumulation of thick, viscous mucus and mucus plaques that cannot be cleared effectively and provide a rich breeding ground for a spectrum of bacterial and fungal communities. The subsequent infections often become chronic and respond poorly to antibiotic treatments, with outcomes sometimes only weakly correlated with the drug susceptibility of the target pathogen. Furthermore, in contrast to rapidly resolved acute infections with a single target pathogen, chronic infections commonly involve multi-species bacterial communities, called "infection microbiomes," that develop their own ecological and evolutionary dynamics. It is presently impossible to devise mathematical models of CF in its entirety, but it is feasible to design models for many of the distinct drivers of the disease. Building upon these growing yet isolated modeling efforts, we discuss in the following the feasibility of a multi-scale modeling framework, known as template-and-anchor modeling, that allows the gradual integration of refined sub-models with different granularity. The article first reviews the most important biomedical aspects of CF and subsequently describes mathematical modeling approaches that already exist or have the potential to deepen our understanding of the multitude aspects of the disease and their interrelationships. The conceptual ideas behind the approaches proposed here do not only pertain to CF but are translatable to other systemic diseases. This article is categorized under: Congenital Diseases > Computational Models.

Improving rigor and reproducibility in western blot experiments with the blotRig analysis software.

Western blot is a popular biomolecular analysis method for measuring the relative quantities of independent proteins in complex biological samples. However, variability in quantitative western blot data analysis poses a challenge in designing reproducible experiments. The lack of rigorous quantitative approaches in current western blot statistical methodology may result in irreproducible inferences. Here we describe best practices for the design and analysis of western blot experiments, with examples and demonstrations of how different analytical approaches can lead to widely varying outcomes. To facilitate best practices, we have developed the blotRig tool for designing and analyzing western blot experiments to improve their rigor and reproducibility. The blotRig application includes functions for counterbalancing experimental design by lane position, batch management across gels, and analytics with covariates and random effects.

Protecting the injured central nervous system: Do anesthesia or hypothermia ameliorate secondary injury?

Traumatic injury to the central nervous system (CNS) and stroke initiate a cascade of processes that expand the area of tissue loss. The current review considers recent studies demonstrating that the induction of an anesthetic state or cooling the affected tissue (hypothermia) soon after injury can have a therapeutic effect. We first provide an overview of the neurobiological processes that fuel tissue loss after traumatic brain injury (TBI), spinal cord injury (SCI) and stroke. We then examine the rehabilitative effectiveness of therapeutic anesthesia across a variety of drug categories through a systematic review of papers in the PubMed database. We also review the therapeutic benefits hypothermia, another treatment that quells neural activity. We conclude by considering factors related to the safety, efficacy and timing of treatment, as well as the mechanisms of action. Clinical implications are also discussed.

General Anesthesia Blocks Pain-Induced Hemorrhage and Locomotor Deficits After Spinal Cord Injury in Rats.

Research has shown that engaging pain (nociceptive) pathways after spinal cord injury (SCI) aggravates secondary injury and undermines locomotor recovery. This is significant because SCI is commonly accompanied by additional tissue damage (polytrauma) that drives nociceptive activity. Cutting communication with the brain by means of a surgical transection, or pharmacologically transecting the cord by slowly infusing a sodium channel blocker (lidocaine) rostral to a thoracic contusion, blocks pain-induced hemorrhage. These observations suggest that the adverse effect of pain after SCI depends on supraspinal (brain) systems. We hypothesize that inhibiting brain activity using a general anesthetic (e.g., pentobarbital, isoflurane) should have a protective effect. The present study shows that placing rats in an anesthetic state with pentobarbital or isoflurane 24 h after a lower thoracic contusion injury blocks pain-induced intraspinal inflammation and hemorrhage when administered before pain. Pentobarbital also extends protective effects against locomotor deficits produced by noxious stimulation. Inducing anesthesia after noxious stimulation, however, has no effect. Similarly, subanesthetic dosages of pentobarbital were also ineffective at blocking pain-induced hemorrhage. Also examined were the hemodynamic impacts of both pain and anesthetic delivery after SCI. Peripheral pain-input induced an acute increase in systolic blood pressure; isoflurane and pentobarbital prevent this increase, which may contribute to the protective effect of anesthesia. The results suggest that placing patients with SCI in a state akin to a medically induced coma can have a protective effect that blocks the adverse effects of pain.

Evaluation of different getter substrates using two-dimensional gas chromatography with time of flight mass spectrometry.

While understanding hydrogen uptake by organic based getters such as 1,4-bis(phenylethynyl)benzene (DEB) combined with a palladium(0)bis(dibenzylideneacetone) (Pd(dba)2) catalyst is essential, another crucial element to understand is the decomposition of the DEB, Pd(dba)2, and/or substrate material. The breakdown of these materials may create unwanted volatiles, which may interact with and lead to deterioration of sensitive materials. Moreover, it is critical to understand if different substrates cause the getter and/or catalyst to degrade in different manners. Utilizing comprehensive two-dimensional gas chromatography (GC×GC) with time-of-flight mass spectrometry (TOFMS), the presence of volatiles located in the headspace of various DEB/Pd(dba)2 getter substrates is examined. These samples include a getter infused silicone foam, a hydrogenated getter infused silicone foam, an activated carbon getter pellet, and a hydrogenated activated carbon getter pellet. Application of Fisher ratio (F-ratio) analyses lead to the identification of several compounds that are generated or consumed through the hydrogenation process. These include benzene derivatives such as bibenzyl, benzaldehyde, and vinyl benzoate in the activated carbon pellets and 1,5-diphenyl-3-pentanone, toluene, styrene, and 1-1'(2-pentene 1,5-diyl)bis benzene in the silicone foams, and alkane/alkene derivatives such undecane, 4-tridecene, and decane in the activated carbon pellets and 2,6-dimethyl undecane in the silicone foams. Further comparison of the different hydrogenated getter substrates (e.g. activated carbon pellet and silicone foam) indicates that the different substrates alter the decomposition products created from the degradation of the DEB and Pd(dba)2.

Anti-KIT DNA aptamer-conjugated porous silicon nanoparticles for the targeted detection of gastrointestinal stromal tumors.

Evaluation of Gastrointestinal Stromal Tumors (GIST) during initial clinical staging, surgical intervention, and postoperative management can be challenging. Current imaging modalities (e.g., PET and CT scans) lack sensitivity and specificity. Therefore, advanced clinical imaging modalities that can provide clinically relevant images with high resolution would improve diagnosis. KIT is a tyrosine kinase receptor overexpressed on GIST. Here, the application of a specific DNA aptamer targeting KIT, decorated onto a fluorescently labeled porous silicon nanoparticle (pSiNP), is used for the in vitro & in vivo imaging of GIST. This nanoparticle platform provides high-fidelity GIST imaging with minimal cellular toxicity. An in vitro analysis shows greater than 15-fold specific KIT protein targeting compared to the free KIT aptamer, while in vivo analyses of GIST-burdened mice that had been injected intravenously (IV) with aptamer-conjugated pSiNPs show extensive nanoparticle-to-tumor signal co-localization (>90% co-localization) compared to control particles. This provides an effective platform for which aptamer-conjugated pSiNP constructs can be used for the imaging of KIT-expressing cancers or for the targeted delivery of therapeutics.

Expression of NAC1 Restrains the Memory Formation of CD8+ T Cells during Viral Infection.

Nucleus accumbens-associated protein 1 (NAC1) is a transcription co-factor that has been shown to possess multiple roles in stem cell and cancer biology. However, little is known about its roles in regulation of the immune system. In the current study, we observed that expression of NAC1 impacted the survival of CD8+ T cells in vitro. NAC1-/- CD8+ T cells displayed lower metabolism, including reduced glycolysis and oxidative phosphorylation. In vivo, compared with wild-type (WT) mice, NAC1-/- mice produced a lower response to vaccinia virus (VACV) infection, and viral antigen (Ag)-specific CD8+ T cells decreased more slowly. Additionally, we observed that the NAC1-/- mice demonstrated a stronger memory formation of viral Ag-specific CD8+ T cells post-viral infection. Mechanically, we identified that compared with WT CD8+ T cells, the Interferon Regulatory Factor 4 (IRF4), a key transcription factor in T cell development, was highly expressed in NAC1-/- CD8+ T cells, insinuating that IRF4 could be a critical regulatory target of NAC1 in the memory formation of CD8+ T cells. Our results indicate that NAC1 restrains the memory formation of CD8+ T cells by modulating IRF4, and targeting NAC1 may be exploited as a new approach to boosting CD8+ T cell memory.

Antibiotics Drive Expansion of Rare Pathogens in a Chronic Infection Microbiome Model.

Chronic (long-lasting) infections are globally a major and rising cause of morbidity and mortality. Unlike typical acute infections, chronic infections are ecologically diverse, characterized by the presence of a polymicrobial mix of opportunistic pathogens and human-associated commensals. To address the challenge of chronic infection microbiomes, we focus on a particularly well-characterized disease, cystic fibrosis (CF), where polymicrobial lung infections persist for decades despite frequent exposure to antibiotics. Epidemiological analyses point to conflicting results on the benefits of antibiotic treatment yet are confounded by the dependency of antibiotic exposures on prior pathogen presence, limiting their ability to draw causal inferences on the relationships between antibiotic exposure and pathogen dynamics. To address this limitation, we develop a synthetic infection microbiome model representing CF metacommunity diversity and benchmark on clinical data. We show that in the absence of antibiotics, replicate microbiome structures in a synthetic sputum medium are highly repeatable and dominated by oral commensals. In contrast, challenge with physiologically relevant antibiotic doses leads to substantial community perturbation characterized by multiple alternate pathogen-dominant states and enrichment of drug-resistant species. These results provide evidence that antibiotics can drive the expansion (via competitive release) of previously rare opportunistic pathogens and offer a path toward microbiome-informed conditional treatment strategies. IMPORTANCE We develop and clinically benchmark an experimental model of the cystic fibrosis (CF) lung infection microbiome to investigate the impacts of antibiotic exposures on chronic, polymicrobial infections. We show that a single experimental model defined by metacommunity data can partially recapitulate the diversity of individual microbiome states observed across a population of people with CF. In the absence of antibiotics, we see highly repeatable community structures, dominated by oral microbes. Under clinically relevant antibiotic exposures, we see diverse and frequently pathogen-dominated communities, and a nonevolutionary enrichment of antimicrobial resistance on the community scale, mediated by competitive release. The results highlight the potential importance of nonevolutionary (community-ecological) processes in driving the growing global crisis of increasing antibiotic resistance.

Exergaming for physical activity: A systematic review.

OBJECTIVE: This review evaluates current literature on intensity selection, perceptual responses, activity enjoyment and adherence rates of exergaming. METHODS: The literature search identified manuscripts that investigated exercise intensity, perceptual responses, or exercise adherence of exergaming in young adults. RESULTS: Based on results of 29 studies, the current review suggest some exergaming activities have the potential to elicit moderate to vigorous exercise intensity and could potentially be substituted for traditional exercise. Additionally, exergame activities may aid in the start of exercise adherence by lowering the individual's perceived exertion when playing exergames. Exergaming not only has the potential to enhance enjoyment through an exercise objective but also through the distracting nature of video games. CONCLUSIONS: Exergaming shows potential to be substituted for traditional exercise and could offer a new, varied form of exercise for sedentary individuals. Future research should examine the influence of exergaming experience on intensity selection and adherence rates.

Label-Free Profiling of up to 200 Single-Cell Proteomes per Day Using a Dual-Column Nanoflow Liquid Chromatography Platform.

Single-cell proteomics (SCP) has great potential to advance biomedical research and personalized medicine. The sensitivity of such measurements increases with low-flow separations (<100 nL/min) due to improved ionization efficiency, but the time required for sample loading, column washing, and regeneration in these systems can lead to low measurement throughput and inefficient utilization of the mass spectrometer. Herein, we developed a two-column liquid chromatography (LC) system that dramatically increases the throughput of label-free SCP using two parallel subsystems to multiplex sample loading, online desalting, analysis, and column regeneration. The integration of MS1-based feature matching increased proteome coverage when short LC gradients were used. The high-throughput LC system was reproducible between the columns, with a 4% difference in median peptide abundance and a median CV of 18% across 100 replicate analyses of a single-cell-sized peptide standard. An average of 621, 774, 952, and 1622 protein groups were identified with total analysis times of 7, 10, 15, and 30 min, corresponding to a measurement throughput of 206, 144, 96, and 48 samples per day, respectively. When applied to single HeLa cells, we identified nearly 1000 protein groups per cell using 30 min cycles and 660 protein groups per cell for 15 min cycles. We explored the possibility of measuring cancer therapeutic targets with a pilot study comparing the K562 and Jurkat leukemia cell lines. This work demonstrates the feasibility of high-throughput label-free single-cell proteomics.

Ancient DNA and deep population structure in sub-Saharan African foragers.

Multiple lines of genetic and archaeological evidence suggest that there were major demographic changes in the terminal Late Pleistocene epoch and early Holocene epoch of sub-Saharan Africa1-4. Inferences about this period are challenging to make because demographic shifts in the past 5,000 years have obscured the structures of more ancient populations3,5. Here we present genome-wide ancient DNA data for six individuals from eastern and south-central Africa spanning the past approximately 18,000 years (doubling the time depth of sub-Saharan African ancient DNA), increase the data quality for 15 previously published ancient individuals and analyse these alongside data from 13 other published ancient individuals. The ancestry of the individuals in our study area can be modelled as a geographically structured mixture of three highly divergent source populations, probably reflecting Pleistocene interactions around 80-20 thousand years ago, including deeply diverged eastern and southern African lineages, plus a previously unappreciated ubiquitous distribution of ancestry that occurs in highest proportion today in central African rainforest hunter-gatherers. Once established, this structure remained highly stable, with limited long-range gene flow. These results provide a new line of genetic evidence in support of hypotheses that have emerged from archaeological analyses but remain contested, suggesting increasing regionalization at the end of the Pleistocene epoch.

Noxious Stimulation Induces Acute Hemorrhage and Impairs Long-Term Recovery after Spinal Cord Injury (SCI) in Female Rats: Evidence Estrous Cycle May Have a Modulatory Effect.

Spinal cord injuries (SCIs) are often the result of traumatic accidents, which also produce multiple other injuries (polytrauma). Nociceptive input from associated injuries has been shown to significantly impair recovery post-SCI. Historically, work in our laboratory has focused exclusively on male animals; however, increasing incidence of SCI in females requires research to determine whether pain (nociceptive) input poses the same risk to their recovery. Some animal studies have shown that females demonstrate greater tissue preservation and better locomotor recovery post-SCI. Given this, we examined the effect of sex on SCI recovery in two pain models-intermittent electrical stimulation (shock) to the tail or capsaicin injection to the hindpaw. Female rats received a lower thoracic contusion injury and were exposed to noxious stimulation the next day. The acute effect of noxious input on cardiovascular function, locomotor performance, and hemorrhage were assessed. Treatment with capsaicin or noxious electrical stimulation disrupted locomotor performance, increased blood pressure, and disrupted stepping. Additional experiments examined the long-term consequences of noxious input, demonstrating that both noxious electrical stimulation and capsaicin impair long-term recovery in female rats. Interestingly, injury had a greater effect on behavioral performance when progesterone and estrogen were low (metestrus). Conversely, nociceptive input led to a greater disruption in locomotor performance and produced a greater rise in blood pressure in animals injured during estrus.

Inference of dynamic interaction networks: A comparison between Lotka-Volterra and multivariate autoregressive models.

Networks are ubiquitous throughout biology, spanning the entire range from molecules to food webs and global environmental systems. Yet, despite substantial efforts by the scientific community, the inference of these networks from data still presents a problem that is unsolved in general. One frequent strategy of addressing the structure of networks is the assumption that the interactions among molecular or organismal populations are static and correlative. While often successful, these static methods are no panacea. They usually ignore the asymmetry of relationships between two species and inferences become more challenging if the network nodes represent dynamically changing quantities. Overcoming these challenges, two very different network inference approaches have been proposed in the literature: Lotka-Volterra (LV) models and Multivariate Autoregressive (MAR) models. These models are computational frameworks with different mathematical structures which, nevertheless, have both been proposed for the same purpose of inferring the interactions within coexisting population networks from observed time-series data. Here, we assess these dynamic network inference methods for the first time in a side-by-side comparison, using both synthetically generated and ecological datasets. Multivariate Autoregressive and Lotka-Volterra models are mathematically equivalent at the steady state, but the results of our comparison suggest that Lotka-Volterra models are generally superior in capturing the dynamics of networks with non-linear dynamics, whereas Multivariate Autoregressive models are better suited for analyses of networks of populations with process noise and close-to linear behavior. To the best of our knowledge, this is the first study comparing LV and MAR approaches. Both frameworks are valuable tools that address slightly different aspects of dynamic networks.

Hemorrhage and Locomotor Deficits Induced by Pain Input after Spinal Cord Injury Are Partially Mediated by Changes in Hemodynamics.

Nociceptive input diminishes recovery and increases lesion area after a spinal cord injury (SCI). Recent work has linked these effects to the expansion of hemorrhage at the site of injury. The current article examines whether these adverse effects are linked to a pain-induced rise in blood pressure (BP) and/or flow. Male rats with a low-thoracic SCI were treated with noxious input (electrical stimulation [shock] or capsaicin) soon after injury. Locomotor recovery and BP were assessed throughout. Tissues were collected 3 h, 24 h, or 21 days later. Both electrical stimulation and capsaicin undermined locomotor function and increased the area of hemorrhage. Changes in BP/flow varied depending on type of noxious input, with only shock producing changes in BP. Providing behavioral control over the termination of noxious stimulation attenuated the rise in BP and hemorrhage. Pretreatment with the α-1 adrenergic receptor inverse agonist, prazosin, reduced the stimulation-induced rise in BP and hemorrhage. Prazosin also attenuated the adverse effect that noxious stimulation has on long-term recovery. Administration of the adrenergic agonist, norepinephrine 1 day after injury induced an increase in BP and disrupted locomotor function, but had little effect on hemorrhage. Further, inducing a rise in BP/flow using norepinephrine undermined long-term recovery and increased tissue loss. Mediational analyses suggest that the pain-induced rise in blood flow may foster hemorrhage after SCI. Increased BP appears to act through an independent process to adversely affect locomotor performance, tissue sparing, and long-term recovery.

Quantifying Mediators of Racial Disparities in Knee Osteoarthritis Outcome Scores: A Cross-Sectional Analysis.

Studies on symptomatic osteoarthritis suggest that Black patients report worse pain and symptoms compared with White patients with osteoarthritis. In this study, we aimed to quantify the relationship among variables such as overall health and socioeconomic status that may contribute to disparities in patient-reported outcomes. METHODS: A total of 223 patients were enrolled. A mediation analysis was used to evaluate cross-sectional associations between race and the Knee injury and Osteoarthritis Outcome Score (KOOS) questionnaire, which was administered to patients prior to undergoing primary total knee arthroplasty. RESULTS: Black patients had worse KOOS pain, symptoms, and activities of daily living subscale scores than White patients. In our cohort, Black patients were younger, more likely to be female, and more likely to report lower educational status. We identified age, sex, Charlson Comorbidity Index, and education as partial mediators of racial disparities in KOOS subscale scores. Insurance status, deformity, radiographic (Kellgren-Lawrence) grade, C-reactive protein level, marital status, body mass index, and income did not show mediating effects. We found that, if age and sex were equal in both cohorts, the racial disparity in KOOS symptom scores would be reduced by 20.7% and 9.1%, respectively (95% confidence intervals [CIs], -5.1% to 47% and -5.5% to 26.3%). For KOOS pain scores, age and education level explained 18.9% and 5.1% of the racial disparity (95% CIs, -0.6% to 37% and -10.8% to 22.9%). Finally, for KOOS activities of daily living scores, education level explained 3.2% of the disparity (95% CI, -19.4% to 26.6%). CONCLUSIONS: No single factor in our study completely explained the racial disparity in KOOS scores, but our findings did suggest that several factors can combine to mediate this disparity in outcome scores. Quantification of variables that mediate racial disparity can help to build models for risk adjustment, pinpoint vulnerable populations, and identify primary points of intervention. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Early human impacts and ecosystem reorganization in southern-central Africa.

Modern Homo sapiens engage in substantial ecosystem modification, but it is difficult to detect the origins or early consequences of these behaviors. Archaeological, geochronological, geomorphological, and paleoenvironmental data from northern Malawi document a changing relationship between forager presence, ecosystem organization, and alluvial fan formation in the Late Pleistocene. Dense concentrations of Middle Stone Age artifacts and alluvial fan systems formed after ca. 92 thousand years ago, within a paleoecological context with no analog in the preceding half-million-year record. Archaeological data and principal coordinates analysis indicate that early anthropogenic fire relaxed seasonal constraints on ignitions, influencing vegetation composition and erosion. This operated in tandem with climate-driven changes in precipitation to culminate in an ecological transition to an early, pre-agricultural anthropogenic landscape.

TGF-ß1-mediated transition of resident fibroblasts to cancer-associated fibroblasts promotes cancer metastasis in gastrointestinal stromal tumor.

Cancer-associated fibroblasts (CAFs) are the most abundant cells in the tumor microenvironment. Crosstalk between tumor cells and CAFs contributes to tumor survival in most epithelial cancers. Recently, utilizing gastrointestinal stromal tumor (GIST) as a model for sarcomas, we identified paracrine networks by which CAFs promote tumor progression and metastasis. However, the mechanisms by which CAFs arise in sarcomas remain unclear. Here, RNA sequencing analysis revealed that transforming growth factor-ß1 (TGF-ß1) is highly expressed in both tumor cells and CAFs. To determine the functional role of TGF-ß1, we treated normal gastric fibroblasts (GFs) with recombinant TGF-ß1, which caused the GFs to adopt a more stellate morphology, as well as increased the mRNA expression of CAF-mediated genes (CCL2, RAB3B, and TNC) and genes encoding fibroblast growth factors (FGFs). Moreover, while either GIST or CAF conditioned media enhanced the transition from GFs to CAFs, a TGF-ß1-blocking antibody attenuated this effect. Transwell migration assays revealed that the TGF-ß1-mediated transition from GFs to CAFs enhanced tumor cell migration. This migratory effect was abrogated by an anti-TGF-ß1 antibody, suggesting that TGF-ß1 secreted from GIST cells or CAFs is associated with GIST migration via GF-to-CAF transition. In addition, the murine spleen-to-liver metastasis model showed that GF pre-treated with TGF-ß1 promoted GIST metastasis. Collectively, these findings reveal unappreciated crosstalk among tumor cells, CAFs, and normal resident fibroblasts in the stroma of sarcomas, which enhances a GF-to-CAF transition associated with tumor migration and metastasis.

Contribution of Brain Processes to Tissue Loss After Spinal Cord Injury: Does a Pain-Induced Rise in Blood Pressure Fuel Hemorrhage?

Pain (nociceptive) input soon after spinal cord injury (SCI) expands the area of tissue loss (secondary injury) and impairs long-term recovery. Evidence suggests that nociceptive stimulation has this effect because it promotes acute hemorrhage. Disrupting communication with the brain blocks this effect. The current study examined whether rostral systems exacerbate tissue loss because pain input drives an increase in systolic blood pressure (BP) and flow that fuels blood infiltration. Rats received a moderate contusion injury to the lower thoracic (T12) spinal cord. Communication with rostral processes was disrupted by cutting the spinal cord 18 h later at T2. Noxious electrical stimulation (shock) applied to the tail (Experiment 1), or application of the irritant capsaicin to one hind paw (Experiment 2), increased hemorrhage at the site of injury. Shock, but not capsaicin, increased systolic BP and tail blood flow in sham-operated rats. Cutting communication with the brain blocked the shock-induced increase in systolic BP and tail blood flow. Experiment 3 examined the effect of artificially driving a rise in BP with norepinephrine (NE) in animals that received shock. Spinal transection attenuated hemorrhage in vehicle-treated rats. Treatment with NE drove a robust increase in BP and tail blood flow but did not increase the extent of hemorrhage. The results suggest pain input after SCI can engage rostral processes that fuel hemorrhage and drive sustained cardiovascular output. An increase in BP was not, however, necessary or sufficient to drive hemorrhage, implicating other brain-dependent processes.