G3BPs tether the TSC complex to lysosomes and suppress mTORC1 signaling.

Ras GTPase-activating protein-binding proteins 1 and 2 (G3BP1 and G3BP2, respectively) are widely recognized as core components of stress granules (SGs). We report that G3BPs reside at the cytoplasmic surface of lysosomes. They act in a non-redundant manner to anchor the tuberous sclerosis complex (TSC) protein complex to lysosomes and suppress activation of the metabolic master regulator mechanistic target of rapamycin complex 1 (mTORC1) by amino acids and insulin. Like the TSC complex, G3BP1 deficiency elicits phenotypes related to mTORC1 hyperactivity. In the context of tumors, low G3BP1 levels enhance mTORC1-driven breast cancer cell motility and correlate with adverse outcomes in patients. Furthermore, G3bp1 inhibition in zebrafish disturbs neuronal development and function, leading to white matter heterotopia and neuronal hyperactivity. Thus, G3BPs are not only core components of SGs but also a key element of lysosomal TSC-mTORC1 signaling.

Panomics reveals patient individuality as the major driver of colorectal cancer progression.

BACKGROUND: Colorectal cancer (CRC) is one of the most prevalent cancers, with over one million new cases per year. Overall, prognosis of CRC largely depends on the disease stage and metastatic status. As precision oncology for patients with CRC continues to improve, this study aimed to integrate genomic, transcriptomic, and proteomic analyses to identify significant differences in expression during CRC progression using a unique set of paired patient samples while considering tumour heterogeneity. METHODS: We analysed fresh-frozen tissue samples prepared under strict cryogenic conditions of matched healthy colon mucosa, colorectal carcinoma, and liver metastasis from the same patients. Somatic mutations of known cancer-related genes were analysed using Illumina's TruSeq Amplicon Cancer Panel; the transcriptome was assessed comprehensively using Clariom D microarrays. The global proteome was evaluated by liquid chromatography-coupled mass spectrometry (LC‒MS/MS) and validated by two-dimensional difference in-gel electrophoresis. Subsequent unsupervised principal component clustering, statistical comparisons, and gene set enrichment analyses were calculated based on differential expression results. RESULTS: Although panomics revealed low RNA and protein expression of CA1, CLCA1, MATN2, AHCYL2, and FCGBP in malignant tissues compared to healthy colon mucosa, no differentially expressed RNA or protein targets were detected between tumour and metastatic tissues. Subsequent intra-patient comparisons revealed highly specific expression differences (e.g., SRSF3, OLFM4, and CEACAM5) associated with patient-specific transcriptomes and proteomes. CONCLUSION: Our research results highlight the importance of inter- and intra-tumour heterogeneity as well as individual, patient-paired evaluations for clinical studies. In addition to changes among groups reflecting CRC progression, we identified significant expression differences between normal colon mucosa, primary tumour, and liver metastasis samples from individuals, which might accelerate implementation of precision oncology in the future.

Altered Left Ventricular Myocardial Deformation in Young Women With Borderline Personality Disorder: An Echocardiographic Study.

OBJECTIVE: Borderline personality disorder (BPD) is characterized by intense mood swings, impulsivity, self-injurious behavior, poor anger control, fear of abandonment, and unstable interpersonal relationships. BPD is also associated with a heightened risk of cardiovascular disease, whereby the underlying mechanisms are insufficiently understood. Accordingly, the present study set out to examine whether individuals with BPD would show abnormal myocardial deformation and to explore the role of potential risk factors, including maladaptive stress responsivity, childhood trauma, and current stress exposure. METHODS: Fifty female patients diagnosed with BPD and 50 controls matched for sex and age underwent echocardiography to determine the global longitudinal strain (GLS) of the left ventricle. In addition, childhood trauma, chronic stress, and "allostatic load" were determined, as well as borderline symptom severity and common risk factors for cardiovascular disease. RESULTS: Aside from a significantly greater GLS in BPD patients, a multivariable regression analysis revealed that allostatic load (ß = 0.225, p = .048) was significantly associated with GLS, with childhood trauma (ß = 0.279, p = .062) approaching significance. Conversely, smoking (p = .867), chronic stress (p = .193), and borderline symptom severity (p = .342) were not associated with GLS, even though bivariate correlations were significant. CONCLUSIONS: Somatically healthy women with BPD display subtle signs of increased GLS, which is associated with allostatic load as an indicator of the "wear-and-tear" of the body. The association between childhood trauma with GLS was of similar strength but did not reach the threshold for statistical significance. This finding may support the need for primary prevention of somatic consequences of maladaptive stress responsivity in psychiatric patients.

The prostaglandin E2 receptor EP3 controls CC-chemokine ligand 2-mediated neuropathic pain induced by mechanical nerve damage.

Prostaglandin (PG) E2 is an important lipid mediator that is involved in several pathophysiological processes contributing to fever, inflammation, and pain. Previous studies have shown that early and continuous application of nonsteroidal anti-inflammatory drugs significantly reduces pain behavior in the spared nerve injury (SNI) model for trauma-induced neuropathic pain. However, the role of PGE2 and its receptors in the development and maintenance of neuropathic pain is incompletely understood but may help inform strategies for pain management. Here, we sought to define the nociceptive roles of the individual PGE2 receptors (EP1-4) in the SNI model using EP knockout mice. We found that PGE2 levels at the site of injury were increased and that the expression of the terminal synthase for PGE2, cytosolic PGE synthase was up-regulated in resident positive macrophages located within the damaged nerve. Only genetic deletion of the EP3 receptor affected nociceptive behavior and reduced the development of late-stage mechanical allodynia as well as recruitment of immune cells to the injured nerve. Importantly, EP3 activation induced the release of CC-chemokine ligand 2 (CCL2), and antagonists against the CCL2 receptor reduced mechanical allodynia in WT but not in EP3 knockout mice. We conclude that selective inhibition of EP3 might present a potential approach for reducing chronic neuropathic pain.

Myc binding protein 2 suppresses M2-like phenotypes in macrophages during zymosan-induced inflammation in mice.

MYCBP2 is an E3 ubiquitin ligase, which is well characterized as a key element in the inhibition of neuronal growth, synapse formation and synaptic strength by regulating several signaling pathways. Although MYCBP2 was suspected to be expressed also in immune cells, to date nothing is known about its role in inflammation. We used Multi-epitope ligand cartography (MELC), a method for multiple sequential immunohistology, to show that MYCBP2 is strongly expressed in monocyte-derived macrophages during zymosan-induced inflammation. We generated a myeloid-specific knockout mouse and found that loss of MYCBP2 in myeloid cells reduced nociceptive (painful) behavior during the resolution phase (1-3 days after zymosan injection). Quantitative MELC analyses and flow cytometric analysis showed an increased number of CD206-expressing macrophages in the inflamed paw tissue. Fittingly, CD206 and arginase 1 expression was upregulated in MYCBP2-deficient bone marrow-derived macrophages after polarization with IL10 or IL4. The regulation of protein expression in these macrophages by MYCBP2 varied depending on the polarization signal. The increased IL10-induced CD206 expression in MYCBP2-deficient macrophages was mediated by p38 MAPK, while IL4-induced CD206 expression in MYCBP2-deficient macrophages was mediated by protein kinase A.

Real-time optoacoustic temperature determination on cell cultures during heat exposure: a feasibility study.

Objective/Purpose: In order to study the effects of hyperthermia and other temperature-related effects on cells and tissues, determining the precise time/temperature course is crucial. Here we present a non-contact optoacoustic technique, which provides temperatures during heating of cultured cells with scalable temporal and spatial resolution. METHODS: A thulium laser (1.94 µm) with a maximum power of 15 W quickly and efficiently heats cells in a culture dish because of low penetration depth (1/e penetration depths of 78 µm) of the radiation in water. A repetitively Q-switched holmium laser (2.1 µm) is used simultaneously to probe temperatures at different locations in the dish by using the photoacoustic effect. Due to thermoelastic expansion of water, pressure waves are emitted and measured with an ultrasonic hydrophone at the side of the dish. The amplitudes of the waves are temperature dependent and can be used to calculate the temperature/time course at any location of probing. RESULTS: We measured temperatures of up to 55 °C with a heating power of 6 W after 10 s, and subsequent lateral temperature profiles over time. Within this profile, temperature fluctuations were found, likely owing to thermal convection and water circulation. By using cultured retinal pigment epithelial cells, it is shown that the probe laser pulses alone cause no biological damage, while immediate cell damage occurs when heating for 10 s at temperatures exceeding 45 °C. CONCLUSIONS: This method shows great potential not only as a noninvasive, non-contact method to determine temperature/time responses of cells in culture, but also for complex tissue and other materials.

The leukotriene B4 receptors BLT1 and BLT2 form an antagonistic sensitizing system in peripheral sensory neurons.

Sensitization of the heat-activated ion channel transient receptor potential vanilloid 1 (TRPV1) through lipids is a fundamental mechanism during inflammation-induced peripheral sensitization. Leukotriene B4 is a proinflammatory lipid mediator whose role in peripheral nociceptive sensitization is not well understood to date. Two major G-protein-coupled receptors for leukotriene B4 have been identified: the high-affinity receptor BLT1 and the low-affinity receptor BLT2. Transcriptional screening for the expression G-protein-coupled receptors in murine dorsal root ganglia showed that both receptors were among the highest expressed in dorsal root ganglia. Calcium imaging revealed a sensitization of TRPV1-mediated calcium increases in a relative narrow concentration range for leukotriene B4 (100-200 nm). Selective antagonists and neurons from knock-out mice demonstrated a BLT1-dependent sensitization of TRPV1-mediated calcium increases. Accordingly, leukotriene B4-induced thermal hyperalgesia was mediated through BLT1 and TRPV1 as shown using the respective knock-out mice. Importantly, higher leukotriene B4 concentrations (>0.5 µm) and BLT2 agonists abolished sensitization of the TRPV1-mediated calcium increases. Also, BLT2 activation inhibited protein kinase C- and protein kinase A-mediated sensitization processes through the phosphatase calcineurin. Consequently, a selective BLT2-receptor agonist increased thermal and mechanical withdrawal thresholds during zymosan-induced inflammation. In accordance with these data, immunohistochemical analysis showed that both leukotriene B4 receptors were expressed in peripheral sensory neurons. Thus, the data show that the two leukotriene B4 receptors have opposing roles in the sensitization of peripheral sensory neurons forming a self-restricting system.

Expression of heat shock protein 70 and cell death kinetics after different thermal impacts on cultured retinal pigment epithelial cells.

Recent technologies are broadening the possibility to treat the retinal pigment epithelium (RPE) with different thermal impacts, from sublethal to lethal ranges. Thus temperature-dependent subcellular molecular responses need to be elucidated in more detail. In this study, RPE cell viability and expression of heat shock protein 70 (Hsp70) were investigated after thermal irradiation with different temperature increase using an in-vitro model. Primary porcine RPE cell cultures were irradiated with different laser power of a thulium laser (λ = 1940 nm, beam-diameter 30 mm) for 10 s, such that the maximal temperatures at the center of the culture dish (Tmax) reach 40, 44, 47, 51 or 59 °C after 10-s irradiation. The temperature distribution across the culture dish shows a Gaussian decay from central position to the periphery of the dish. At 3, 24 and 48 h after irradiation cell viability was assessed with fluorescence microscopy using cell viability-indicating fluorescence dyes, followed by the determination of the threshold temperature for apoptotic change and death of RPE cells. Intracellular localization and amount of Hsp70 were investigated with immunofluorescence and western blotting, respectively. The threshold temperature (at the 10th second of irradiation: T10s) for cellular apoptosis and complete cell death showed a decrease over time after irradiation, suggesting a long-term process of thermally induced cell death. For complete cell death the threshold T10s was 52.1 ±â€¯0.6 °C, 50.1 ±â€¯1.4 °C, and 50.1 ±â€¯0.8 °C, for 3, 24 and 48 h, respectively, whereas for the apoptotic changes 48.6 ±â€¯1.8 °C, 47.2 ±â€¯1.3 °C, and 46.7 ±â€¯0.9 °C, respectively. Quantitative analysis of Hsp70 with western blotting showed a significant increase in intracellular Hsp70 at lethal irradiation with Tmax ≥ 51 °C, up to 19.6 ±â€¯2.3 fold after 48 h at 59 °C, whereas sub-lethal irradiations with Tmax ≤ 44 °C led to a slight tendency of time-dependent increases (up to 1.8 ±â€¯1.1 fold) over 48 h. Immunostainings for Hsp70 showed a circle- or ring-pattern of the Hsp70 staining during 3-48 h after irradiation, and the range of the 1st and 3rd quartiles of T10s for heat-induced Hsp70 expression over this time period was between 44.8 °C and 48.2 °C. A very strong staining of Hsp70 was observed at the border to the damaged zone, where many cells show the strong staining in the whole cytoplasmic space, while some cells in the nucleus, or some cells show the signs of cell migration and proliferation. Moreover, among the cells showing high intensity of Hsp70 staining, there are small round cells like apoptotic cells. Results suggest that RPE cell death after thermal irradiation may take time, and mostly undergoes through apoptosis, unless cells are immediately killed. Thermal irradiation-induced Hsp70 expression is not only temperature-dependent, but also depends largely on the existence of neighboring cell death, suggesting the crucial role of Hsp70 in apoptosis and wound healing processes of RPE cells. The increase of Hsp70 over 24-48 h indicates its long-term roles in cell responses both after sublethal and lethal thermal laser irradiations.

CD200 selectively upregulates prostaglandin E2 and D2 synthesis in LPS-treated bone marrow-derived macrophages.

The CD200/CD200R signalling pathway downregulates the synthesis of proinflammatory mediators and induces the synthesis of antiinflammatory mediators in macrophages and microglia. However, very little is known about the effect of this immunosuppressive pathway on the synthesis of lipid mediators. Therefore, we determined the synthesis of 35 lipids spanning 5 different lipid families in bone marrow-derived macrophages, which were treated with interleukin (IL) 4, IL10, lipopolysaccharide (LPS), or interferon γ (IFNγ) in absence and presence of CD200. Out of these conditions the only significant effect of CD200 was an increased synthesis of prostaglandin (PG) E2 and D2 in the presence of LPS. Accordingly, mRNA levels of cyclooxygenase-2, microsomal PGE2 synthase-1 and hematopoietic PGD synthase were upregulated by CD200 in presence of LPS. During Complete Freund's Adjuvant (CFA-) induced inflammation mPGES-1 was expressed in monocyte-derived macrophages and its expression was stronger in CD200R-positive than in CD200R-negative macrophages.

Stress-Mediated Abnormalities in Regional Myocardial Wall Motion in Young Women with a History of Psychological Trauma.

BACKGROUND: Psychosocial stress has been associated with the development and progression of atherosclerotic cardiovascular disease (CVD). Previously, we reported subtle differences in global longitudinal strain in somatically healthy women with a psychiatric diagnosis of borderline personality disorder (BPD). This study aimed to investigate the impact of BPD on segmental myocardial wall motion using speckle tracking echocardiography (STE) analysis. METHODS: A total of 100 women aged between 18 and 38 years were included in this study. Fifty patients meeting the diagnostic criteria for BPD were recruited from the Department of Psychiatry (LWL-University Hospital Bochum) and compared with fifty age-matched healthy control subjects without previous cardiac disease. Laboratory tests and STE were performed with segmental wall motion analysis. RESULTS: The BPD group had a higher prevalence of risk factors for CVD, with smoking and obesity being predominant, when compared with the control group. Other cardiovascular parameters such as blood pressure, glucose, and cholesterol levels were also elevated, even though not to pathological values. Moreover, in the STE analysis, the BPD group consistently exhibited decreased deformation in nine myocardial wall regions compared with the control group, along with a shift toward higher values in the distribution of peak pathological segments. Additionally, significantly higher values of free thyroxine concentration and thyroid's secretory capacity were observed in the BPD group, despite falling within the (high-) normal range. CONCLUSIONS: BPD is associated with chronic stress, classical risk factors, and myocardial wall motion abnormalities. Further exploration is warranted to investigate the relationship between high-normal thyroid metabolism, these risk factors, and myocardial function in BPD patients. Long-term follow-up studies would be valuable in confirming the potential for predicting adverse events.

Homocysteine as a potential indicator of endothelial dysfunction and cardiovascular risk in female patients with borderline personality disorder.

BACKGROUND: There is increasing evidence suggesting that patients with Borderline Personality Disorder (BPD) are at greater risk of developing cardiovascular diseases (CVD) compared to the general population. Homocysteine (Hcy) has been discussed as a serum marker for endothelial dysfunction as a mechanism involved in CVD and has been shown to be associated with numerous psychiatric conditions. Pathophysiologically, there seems to be a link between Hcy and psychological stress mediated by abnormal activity of the autonomic nervous system. Accordingly, the present study sought to examine Hcy in BPD and to explore possible associations with clinical parameters. METHODS: Plasma Hcy levels as well as conventional cardiovascular risk factors, such as blood pressure, BMI, smoking habits, HbA1c, HDL, LDL, and cholesterol, were examined in 49 young female in-patients diagnosed with BPD and 50 psychologically healthy control subjects matched for age and sex. Assessment of borderline symptom severity, childhood trauma, exposure to chronic stress, and quality of sleep was performed using self-reported questionnaires. RESULTS: BPD patients showed significantly higher mean plasma Hcy concentrations compared to controls, though below ranges considered pathological. Moreover, Hcy correlated significantly with the severity of childhood trauma, chronic stress, and subjective sleep disturbances. In a regression model BPD diagnosis was found to predict Hcy levels best. CONCLUSION: In conclusion, young female BPD patients with no history of CVD show higher, though non-pathological, Hcy levels compared to healthy controls. Our findings seem to support the assumption that BPD is associated with increased risk of CVD, and that Hcy could serve as potential marker for risk evaluation of midlife CVD in BPD patients.

Biomarkers in Liquid Biopsies for Prediction of Early Liver Metastases in Pancreatic Cancer.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive solid malignancies with poor survival rates. Only 20% of the patients are eligible for R0-surgical resection, presenting with early relapses, mainly in the liver. PDAC patients with hepatic metastases have a worse outcome compared to patients with metastases at other sites. Early detection of hepatic spread bears the potential to improve patient outcomes. Thus, this study sought for serum-based perioperative biomarkers allowing discrimination of early (EHMS ≤ 12 months) and late hepatic metastatic spread (LHMS > 12 months). Serum samples from 83 resectable PDAC patients were divided into EHMS and LHMS and analyzed for levels of inflammatory mediators by LEGENDplexTM, which was validated and extended by Olink® analysis. CA19-9 serum levels served as control. Results were correlated with clinicopathological data. While serum CA19-9 levels were comparable, Olink® analysis confirmed distinct differences between both groups. It revealed significantly elevated levels of factors involved in chemotaxis and migration of immune cells, immune activity, and cell growth in serum of LHMS-patients. Overall, Olink® analysis identified a comprehensive biomarker panel in serum of PDAC patients that could provide the basis for predicting LHMS. However, further studies with larger cohorts are required for its clinical translation.

Cardiac parasympathetic activity in female patients with borderline personality disorder predicts approach/avoidance behavior towards angry faces.

Among other features, Borderline Personality Disorder (BPD) is characterized by difficulties in regulating affiliative behavior. Here, we examined the association of heart rate variability (HRV) with approach/avoidance behavior in BPD. Accordingly, HRV parameters (RMSSD and HF-HRV) were measured in 42 female patients with BPD and 50 controls before performing an Approach Avoidance Task (AAT). Half of participants were previously exposed to social exclusion in a virtual ball-tossing game. Overall, HRV was lower in patients with BPD compared to controls. Moreover, low HRV was associated with attenuated approach for angry faces with an averted gaze. Following social exclusion, the BPD group showed the largest approach to happy faces and the least approach for angry faces, a pattern which differed from controls and patients in the control condition. Our findings indicate an association of cardiac parasympathetic activity with social behavior. Moreover, social exclusion may foster avoidance of angry faces in BPD patients.

A large-scale resource for tissue-specific CRISPR mutagenesis in Drosophila.

Genetic screens are powerful tools for the functional annotation of genomes. In the context of multicellular organisms, interrogation of gene function is greatly facilitated by methods that allow spatial and temporal control of gene abrogation. Here, we describe a large-scale transgenic short guide (sg) RNA library for efficient CRISPR-based disruption of specific target genes in a constitutive or conditional manner. The library consists currently of more than 2600 plasmids and 1700 fly lines with a focus on targeting kinases, phosphatases and transcription factors, each expressing two sgRNAs under control of the Gal4/UAS system. We show that conditional CRISPR mutagenesis is robust across many target genes and can be efficiently employed in various somatic tissues, as well as the germline. In order to prevent artefacts commonly associated with excessive amounts of Cas9 protein, we have developed a series of novel UAS-Cas9 transgenes, which allow fine tuning of Cas9 expression to achieve high gene editing activity without detectable toxicity. Functional assays, as well as direct sequencing of genomic sgRNA target sites, indicates that the vast majority of transgenic sgRNA lines mediate efficient gene disruption. Furthermore, we conducted the so far largest fully transgenic CRISPR screen in any metazoan organism, which further supported the high efficiency and accuracy of our library and revealed many so far uncharacterized genes essential for development.

Twenty years after the release of the sequence of the human genome, the role of many genes is still unknown. This is partly because some of these genes may only be active in specific types of cells or for short periods of time, which makes them difficult to study. A powerful way to gather information about human genes is to examine their equivalents in 'model' animals such as fruit flies. Researchers can use genetic methods to create strains of insects where genes are deactivated; evaluating the impact of these manipulations on the animals helps to understand the roles of the defunct genes. However, the current methods struggle to easily delete target genes, especially only in certain cells, or at precise times. Here, Port et al. genetically engineered flies that carry CRISPR-Cas9, a biological system that can be programmed to 'cut' and mutate precise genetic sequences. The insects were also manipulated in such a way that the CRISPR elements could be switched on at will, and their quantity finely tuned. This work resulted in a collection of more than 1,700 fruit fly strains in which specific genes could be deactivated on demand in precise cells. Further experiments confirmed that this CRISPR system could mutate target genes in different parts of the fly, including in the eyes, gut and wings. Port et al. have made their collection of genetically engineered fruit flies publically available, so that other researchers can use the strains in their experiments. The CRISPR technology they refined and developed may also lay the foundation for similar collections in other model organisms.

Human Pancreatic Carcinoma-Associated Fibroblasts Promote Expression of Co-inhibitory Markers on CD4+ and CD8+ T-Cells.

Carcinoma-associated pancreatic fibroblasts (CAFs) are the major type of cells in the stroma of pancreatic ductal adenocarcinomas and besides their pathological release of extracellular matrix proteins, they are also perceived as key contributors to immune evasion. Despite the known relevance of tumor infiltrating lymphocytes in cancers, the interactions between T-cells and CAFs remain largely unexplored. Here, we found that CAFs isolated from tumors of pancreatic cancer patients undergoing surgical resection (n = 15) expressed higher levels of the PD-1 ligands PD-L1 and PD-L2 compared to primary skin fibroblasts from healthy donors. CAFs strongly inhibited T-cell proliferation in a contact-independent fashion. Blocking the activity of prostaglandin E2 (PGE2) by indomethacin partially restored the proliferative capacity of both CD4+ and CD8+ T-cells. After stimulation, the proportion of proliferating T-cells expressing HLA-DR and the proportion of memory T-cells were decreased when CAFs were present compared to T-cells proliferating in the absence of CAFs. Interestingly, CAFs promoted the expression of TIM-3, PD-1, CTLA-4 and LAG-3 in proliferating T-cells. Immunohistochemistry stainings further showed that T-cells residing within the desmoplastic stromal compartment express PD-1, indicating a role for CAFs on co-inhibitory marker expression also in vivo. We further found that PGE2 promoted the expression of PD-1 and TIM-3 on T-cells. Functional assays showed that proliferating T-cells expressing immune checkpoints produced less IFN-γ, TNF-α, and CD107a after restimulation when CAFs had been present. Thus, this indicates that CAFs induce expression of immune checkpoints on CD4+ and CD8+ T-cells, which contribute to a diminished immune function.

The G2A Receptor Controls Polarization of Macrophage by Determining Their Localization Within the Inflamed Tissue.

Macrophages are highly versatile cells, which acquire, depending on their microenvironment, pro- (M1-like), or antiinflammatory (M2-like) phenotypes. Here, we studied the role of the G-protein coupled receptor G2A (GPR132), in chemotactic migration and polarization of macrophages, using the zymosan-model of acute inflammation. G2A-deficient mice showed a reduced zymosan-induced thermal hyperalgesia, which was reversed after macrophage depletion. Fittingly, the number of M1-like macrophages was reduced in the inflamed tissue in G2A-deficient mice. However, G2A activation was not sufficient to promote M1-polarization in bone marrow-derived macrophages. While the number of monocyte-derived macrophages in the inflamed paw was not altered, G2A-deficient mice had less macrophages in the direct vicinity of the origin of inflammation, an area marked by the presence of zymosan, neutrophil accumulation and proinflammatory cytokines. Fittingly neutrophil efferocytosis was decreased in G2A-deficient mice and several lipids, which are released by neutrophils and promote G2A-mediated chemotaxis, were increased in the inflamed tissue. Taken together, G2A is necessary to position macrophages in the proinflammatory microenvironment surrounding the center of inflammation. In absence of G2A the macrophages are localized in an antiinflammatory microenvironment and macrophage polarization is shifted toward M2-like macrophages.

Continuous-wave Thulium Laser for Heating Cultured Cells to Investigate Cellular Thermal Effects.

An original method to heat cultured cells using a 1.94 µm continuous-wave thulium laser for biological assessment is introduced here. Thulium laser radiation is strongly absorbed by water, and the cells at the bottom of the culture dish are heated through thermal diffusion. A laser fiber with a diameter of 365 µm is set about 12 cm above the culture dish, without any optics, such that the laser beam diameter is almost equivalent to the inner diameter of the culture dish (30 mm). By keeping a consistent amount of culture medium in each experiment, it is possible to irradiate the cells with a highly reproducible temperature increase. To calibrate the temperature increase and its distribution in one cell culture dish for each power setting, the temperature was measured during 10 s of irradiation at different positions and at the cellular level. The temperature distribution was represented using a mathematical graphics software program, and its pattern across the culture dish was in Gaussian form. After laser irradiation, different biological experiments could be performed to assess temperature-dependent cell responses. In this manuscript, viability staining (i.e., distinguishing live, apoptotic, and dead cells) is introduced to help determine the threshold temperatures for cell apoptosis and death after different points in time. The advantages of this method are the preciseness of the temperature and the time of heating, as well as its high efficiency in heating cells in a whole cell culture dish. Furthermore, it allows for study with a wide variety of temperatures and time durations, which can be well-controlled by a computerized operating system.