Distinct Activation Profiles Research Articles

Diversity of complement activation in different thyroid diseases

ObjectiveTo investigate complement components expression in both thyroid tissues and serum from patients with Hashimoto's thyroiditis (HT), Graves' disease (GD), and papillary thyroid cancer (PTC). MethodsC1q, mannose binding lectin (MBL), Bb, C4d, C3d and membrane attack complex (MAC) (C5b-9) deposition and complement regulate proteins (CD46, CD55 and CD59) expression in thyroid tissues from HT, GD, PTC, and control groups were examined by IHC. C1q, MBL, Bb, C4d, C3a, and soluble C5b-9 (sC5b-9) serum levels in the HT, GD, PTC, and healthy donor (HD) groups were measured by ELISAs. ResultsMAC deposition was detected in thyroid tissues in the HT, GD and PTC groups, but not the control group. MBL, Bb, C4d, C3d and MAC staining intensities in thyroid tissues were significantly higher in the HT and PTC groups than in the control group (all P < 0.05). The C1q level was higher in HT tissues than in control tissues (both P < 0.05). No complement component had a significant difference in staining intensities between the GD and control groups. CD55 and CD59 expression levels in thyroid tissues were higher in the PTC group than in the HT, GD and control groups (all P < 0.05). Similarly, CD46 levels were higher in HT tissues than in control tissues. Bb, C4d, C3a and sC5b-9 serum levels were significantly increased in HT, GD and PTC patients compared with HDs (all P < 0.05). ConclusionComplement is overactivated in HT and PTC, but not in GD. All the three pathways are activated in HT, and the MBL and alternative complement pathways are activated in PTC. These distinct complement activation profiles may participate in HT, GD and PTC pathogenesis.

Structure and Function of the β-Asp-Arg Polymerase Cyanophycin Synthetase 2.

Cyanophycin is a biopolymer composed of long chains of β-Asp-Arg. It is widespread in nature, being synthesized by many clades of bacteria, which use it as a cellular reservoir of nitrogen, carbon, and energy. Two enzymes are known to produce cyanophycin: cyanophycin synthetase 1 (CphA1), which builds cyanophycin from the amino acids Asp and Arg by alternating between two separate reactions for backbone extension and side chain modification, and cyanophycin synthetase 2 (CphA2), which polymerizes β-Asp-Arg dipeptides. CphA2 is evolutionarily related to CphA1, but questions about CphA2's altered structure and function remain unresolved. Cyanophycin and related molecules have drawn interest as green biopolymers. Because it only has a single active site, CphA2 could be more useful than CphA1 for biotechnological applications seeking to produce modified cyanophycin. In this study, we report biochemical assays on nine cyanobacterial CphA2 enzymes and report the crystal structure of CphA2 from Gloeothece citriformis at 3.0 Å resolution. The structure reveals a homodimeric, three-domain architecture. One domain harbors the polymerization active site and the two other domains have structural roles. The structure and biochemical assays explain how CphA2 binds and polymerizes β-Asp-Arg and highlights differences in in vitro oligomerization and activity between CphA2 enzymes. Using the structure and distinct activity profile as a guide, we introduced a single point mutation that converted Gloeothece citriformis CphA2 from a primer-dependent enzyme into a primer-independent enzyme.

Loving lunch in junior high: Lunchtime activities and a sense of belonging in school.

We explore student lunchtime experiences as they relate to student sense of belonging. We use SPSS Two-Step cluster analysis and logistic regression of data from a schoolwide survey (n = 830) in the United States. Stepwise modeling is used to determine the importance of clusters representing lunchtime activity preferences and love of lunch on belonging scores. Loving lunch significantly positively affects school belonging. Students naturally group into five distinct different activity profiles based on lunchtime preferences. These profiles are significantly related to a sense of belonging. Being active with peers during lunch was most strongly correlated with sense of belonging. Lunchtime warrants more attention for fostering a sense of belonging in the school community. Broadening lunchtime activity options, especially in schools where there are few available ways for socializing and being active, has the potential to support the diverse needs of students and increase belonging.

Phenolic Lipids Derived from Cashew Nut Shell Liquid to Treat Metabolic Diseases.

Metabolic diseases are increasing at staggering rates globally. The peroxisome proliferator-activated receptors (PPARα/γ/δ) are fatty acid sensors that help mitigate imbalances between energy uptake and utilization. Herein, we report compounds derived from phenolic lipids present in cashew nut shell liquid (CNSL), an abundant waste byproduct, in an effort to create effective, accessible, and sustainable drugs. Derivatives of anacardic acid and cardanol were tested for PPAR activity in HEK293 cell co-transfection assays, primary hepatocytes, and 3T3-L1 adipocytes. In vivo studies using PPAR-expressing zebrafish embryos identified CNSL derivatives with varying tissue-specific activities. LDT409 (23) is an analogue of cardanol with partial agonist activity for PPARα and PPARγ. Pharmacokinetic profiling showed that 23 is orally bioavailable with a half-life of 4 h in mice. CNSL derivatives represent a sustainable source of selective PPAR modulators with balanced intermediate affinities (EC50 ∼ 100 nM to 10 μM) that provide distinct and favorable gene activation profiles for the treatment of diabetes and obesity.

Clustering Accelerometer Activity Patterns from the UK Biobank Cohort.

Many researchers are beginning to adopt the use of wrist-worn accelerometers to objectively measure personal activity levels. Data from these devices are often used to summarise such activity in terms of averages, variances, exceedances, and patterns within a profile. In this study, we report the development of a clustering utilising the whole activity profile. This was achieved using the robust clustering technique of k-medoids applied to an extensive data set of over 90,000 activity profiles, collected as part of the UK Biobank study. We identified nine distinct activity profiles in these data, which captured both the pattern of activity throughout a week and the intensity of the activity: “Active 9 to 5”, “Active”, “Morning Movers”, “Get up and Active”, “Live for the Weekend”, “Moderates”, “Leisurely 9 to 5”, “Sedate” and “Inactive”. These patterns are differentiated by sociodemographic, socioeconomic, and health and circadian rhythm data collected by UK Biobank. The utility of these findings are that they sit alongside existing summary measures of physical activity to provide a way to typify distinct activity patterns that may help to explain other health and morbidity outcomes, e.g., BMI or COVID-19. This research will be returned to the UK Biobank for other researchers to use.

Activation of Fibroblasts in Skin Cancer

Fibroblasts have emerged as a dominant component of the tumor microenvironment, but despite the surging interest in the activation of fibroblasts and their role in cancer, they remain an elusive and complex cell type. In this perspective, we discuss the phenotypic plasticity of cancer-associated fibroblasts (CAFs) in melanoma and nonmelanoma skin cancer identified by genome-wide transcriptomic studies and focus on the molecular pathways underlying their activation. These studies reveal distinct fibroblast activation profiles depending on tumor type and stage. A better understanding of skin CAF heterogeneity in origin and function will guide novel therapeutic approaches targeting this cell type in clinical cancer care.

Diagnostic value of actigraphy in hypersomnolence disorders

ObjectiveDifferentiating between the central hypersomnias presents a challenge to the diagnosis of patients with hypersomnolence. Actitigraphy may support efforts to distinguish them.We aimed to evaluate: 1) the ability of actigraphy to quantify sleep continuity measures in comparison with polysomnography in patients with hypersomnolence; 2) whether actigraphy can distinguish patients with hypersomnolence with normal hypocretin-1 in cerebrospinal fluid from patients with narcolepsy type 1 and from sleep-healthy controls; and 3) the distinct activity profiles and circadian rhythms of patients with narcolepsy type 1, patients with hypersomnolence with normal hypocretin-1 in cerebrospinal fluid, and sleep-healthy controls. MethodPolysomnography, multiple sleep latency tests and actigraphy were conducted in 14 patients with narcolepsy type 1, 29 patients with hypersomnolence with normal hypocretin-1 in cerebrospinal fluid and 15 sleep-healthy controls. ResultsActigraphy quantified several sleep continuity measures consistently with polysomnography in all the patients. Actigraphy distinguished patients with hypersomnolence with normal hypocretin-1 in cerebrospinal fluid from patients with narcolepsy type 1 and sleep-healthy controls. Patients with narcolepsy type 1 had poor sleep quality and altered circadian rest-activity rhythm compared with controls. ConclusionActigraphy is an adequate tool for establishing the amount of night sleep and supports the differential diagnosis of patients with hypersomnolence.

From stretch to deflection: the importance of context in the activation of mammalian, mechanically activated ion channels.

The ability of cells to convert mechanical perturbations into biochemical information is an essential aspect of mammalian physiology. The molecules that mediate such mechanotransduction include mechanically activated ion channels, which directly convert mechanical inputs into electrochemical signals. The unifying feature of these channels is that their open probability increases with the application of a mechanical input. However, the structure, activation profile and sensitivity of distinct mechanically activated ion channels vary from channel to channel. In this review, we discuss how ionic currents can be mechanically evoked and monitored in vitro, and describe the distinct activation profiles displayed by a range of mammalian channels. In addition, we discuss the various mechanisms by which the best-characterized mammalian, mechanically activated ion channel, PIEZO1, can be modulated. The diversity of activation and modulation of these mammalian ion channels suggest that these molecules may facilitate a finely controlled and diverse ability to sense mechanical inputs in mammalian cells.

Reactive astrocyte-driven epileptogenesis is induced by microglia initially activated following status epilepticus.

Extensive activation of glial cells during a latent period has been well documented in various animal models of epilepsy. However, it remains unclear whether activated glial cells contribute to epileptogenesis, i.e., the chronically persistent process leading to epilepsy. Particularly, it is not clear whether interglial communication between different types of glial cells contributes to epileptogenesis, because past literature has mainly focused on one type of glial cell. Here, we show that temporally distinct activation profiles of microglia and astrocytes collaboratively contributed to epileptogenesis in a drug-induced status epilepticus model. We found that reactive microglia appeared first, followed by reactive astrocytes and increased susceptibility to seizures. Reactive astrocytes exhibited larger Ca2+ signals mediated by IP3R2, whereas deletion of this type of Ca2+ signaling reduced seizure susceptibility after status epilepticus. Immediate, but not late, pharmacological inhibition of microglial activation prevented subsequent reactive astrocytes, aberrant astrocyte Ca2+ signaling, and the enhanced seizure susceptibility. These findings indicate that the sequential activation of glial cells constituted a cause of epileptogenesis after status epilepticus. Thus, our findings suggest that the therapeutic target to prevent epilepsy after status epilepticus should be shifted from microglia (early phase) to astrocytes (late phase).

Distinct expression profiles of regulatory RNAs in the response to biocides in Staphylococcus aureus and Enterococcus faecium

The aim of the study was to characterize the antimicrobial activity of clinically-relevant biocides (chlorhexidine digluconate, benzalkonium chloride, PVP-iodine and triclosan) and to determine the sRNA expression profiles under biocide exposure in two major bacterial opportunistic pathogens, Enterococcus faecium and Staphylococcus aureus. In vitro activities were evaluated against S. aureus HG003 and E. faecium Aus0004. We determined MIC, MBC, sub-inhibitory concentrations (SIC) and growth curves under SIC conditions. sRNA expression study under SIC exposure of biocides was performed by RT-qPCR on 3 sRNAs expressed in S. aureus (RNAIII, SprD and SprX) and the first 9 sRNAs identified as expressed in E. faecium. MICs were higher against E. faecium than for S. aureus. Growth curves under increasing biocide concentrations highlighted two types of bactericidal activity: “on/off” effect for chlorhexidine, benzalkonium chloride, PVP-iodine and a “concentration-dependent” activity for triclosan. Exposure to biocide SICs led to an alteration of several sRNA expression profiles, mostly repressed. The distinct biocide activity profiles must be evaluated with other compounds and bacterial species to enrich the prediction of resistance risks associated with biocide usage. Biocide exposure induces various sRNA-mediated responses in both S. aureus and E. faecium, and further investigations are needed to decipher sRNA-driven regulatory networks.

Reactivity and Selectivity in Ruthenium Sulfur-Chelated Diiodo Catalysts.

A trifluoromethyl sulfur-chelated ruthenium benzylidene, Ru-S-CF3 -I, was synthesized and characterized. This latent precatalyst provides a distinct activity and selectivity profiles for olefin metathesis reactions depending on the substrate. For example, 1,3-divinyl-hexahydropentalene derivatives were efficiently obtained by ring-opening metathesis (ROM) of dicyclopentadiene (DCPD). Ru-S-CF3 -I also presented a much more effective photoisomerization process from the inactive cis-diiodo to the active trans-diiodo configuration after exposure to 510 nm (green light), allowing for a wide scope of photoinduced olefin metathesis reactions. DFT calculations suggest a faster formation and enhanced stability of the active trans-diiodo species of Ru-S-CF3 -I compared with Ru-S-Ph-I, explaining its higher reactivity. In addition, the photochemical release of chloride anions by irradiation of Cl-BODIPY in the presence of DCPD derivatives with diiodo Ru benzylidenes, led to in situ generation of chloride complexes, which quickly produced the corresponding cross-linked polymers. Thus, novel selective pathways that use visible light to guide olefin metathesis based synthetic sequences is presented.

Reactivity and Selectivity in Ruthenium Sulfur‐Chelated Diiodo Catalysts

AbstractA trifluoromethyl sulfur‐chelated ruthenium benzylidene, Ru‐S‐CF3‐I, was synthesized and characterized. This latent precatalyst provides a distinct activity and selectivity profiles for olefin metathesis reactions depending on the substrate. For example, 1,3‐divinyl‐hexahydropentalene derivatives were efficiently obtained by ring‐opening metathesis (ROM) of dicyclopentadiene (DCPD). Ru‐S‐CF3‐I also presented a much more effective photoisomerization process from the inactive cis‐diiodo to the active trans‐diiodo configuration after exposure to 510 nm (green light), allowing for a wide scope of photoinduced olefin metathesis reactions. DFT calculations suggest a faster formation and enhanced stability of the active trans‐diiodo species of Ru‐S‐CF3‐I compared with Ru‐S‐Ph‐I, explaining its higher reactivity. In addition, the photochemical release of chloride anions by irradiation of Cl‐BODIPY in the presence of DCPD derivatives with diiodo Ru benzylidenes, led to in situ generation of chloride complexes, which quickly produced the corresponding cross‐linked polymers. Thus, novel selective pathways that use visible light to guide olefin metathesis based synthetic sequences is presented.

Galectin-1 and platelet factor 4 (CXCL4) induce complementary platelet responses in vitro

Galectin-1 (gal-1) is a carbohydrate-binding lectin with important functions in angiogenesis, immune response, hemostasis and inflammation. Comparable functions are exerted by platelet factor 4 (CXCL4), a chemokine stored in the α-granules of platelets. Previously, gal-1 was found to activate platelets through integrin αIIbβ3. Both gal-1 and CXCL4 have high affinities for polysaccharides, and thus may mutually influence their functions. The aim of this study was to investigate a possible synergism of gal-1 and CXCL4 in platelet activation. Platelets were treated with increasing concentrations of gal-1, CXCL4 or both, and aggregation, integrin activation, P-selectin and phosphatidyl serine (PS) exposure were determined by light transmission aggregometry and by flow cytometry. To investigate the influence of cell surface sialic acid, platelets were treated with neuraminidase prior to stimulation. Gal-1 and CXCL4 were found to colocalize on the platelet surface. Stimulation with gal-1 led to integrin αIIbβ3 activation and to robust platelet aggregation, while CXCL4 weakly triggered aggregation and primarily induced P-selectin expression. Co-incubation of gal-1 and CXCL4 potentiated platelet aggregation compared with gal-1 alone. Whereas neither gal-1 and CXCL4 induced PS-exposure on platelets, prior removal of surface sialic acid strongly potentiated PS exposure. In addition, neuraminidase treatment increased the binding of gal-1 to platelets and lowered the activation threshold for gal-1. However, CXCL4 did not affect binding of gal-1 to platelets. Taken together, stimulation of platelets with gal-1 and CXCL4 led to distinct and complementary activation profiles, with additive rather than synergistic effects.

Identification of distinct immune activation profiles in adult humans

Latent infectious agents, microbial translocation, some metabolites and immune cell subpopulations, as well as senescence modulate the level and quality of activation of our immune system. Here, we tested whether various in vivo immune activation profiles may be distinguished in a general population. We measured 43 markers of immune activation by 8-color flow cytometry and ELISA in 150 adults, and performed a double hierarchical clustering of biomarkers and volunteers. We identified five different immune activation profiles. Profile 1 had a high proportion of naïve T cells. By contrast, Profiles 2 and 3 had an elevated percentage of terminally differentiated and of senescent CD4+ T cells and CD8+ T cells, respectively. The fourth profile was characterized by NK cell activation, and the last profile, Profile 5, by a high proportion of monocytes. In search for etiologic factors that could determine these profiles, we observed a high frequency of naïve Treg cells in Profile 1, contrasting with a tendency to a low percentage of Treg cells in Profiles 2 and 3. Moreover, Profile 5 tended to have a high level of 16s ribosomal DNA, a direct marker of microbial translocation. These data are compatible with a model in which specific causes, as the frequency of Treg or the level of microbial translocation, shape specific profiles of immune activation. It will be of interest to analyze whether some of these profiles drive preferentially some morbidities known to be fueled by immune activation, as insulin resistance, atherothrombosis or liver steatosis.

Effects of substance misuse on reward-processing in patients with attention-deficit/hyperactivity disorder.

Attention-Deficit/Hyperactivity Disorder (ADHD) and Substance Use Disorder (SUD) often co-occur and are associated with treatment resistance. Both disorders are characterized by similar reward-processing deficits with decreased striatal responses to reward anticipation, though literature is inconsistent. It is unclear whether substance misuse exaggerates reward-processing deficits observed in ADHD. The aim of this study was to examine substance misuse effects on reward-processing in ADHD. Functional MRI data in a Monetary Incentive Delay (MID) task from a multi-site study were compared across ADHD groups with and without substance misuse (ADHD + SM and ADHD-only, respectively) and healthy controls (n = 40/group, 74 males and 46 females, aged 13.7-25.9 years). Substance misuse was defined as misuse of alcohol, nicotine, or drugs. Groups were matched with presence/absence of parental SUD to avoid interference with SUD trait effects. Compared to ADHD-only and controls, ADHD + SM showed hyperactivation in putamen during reward anticipation. Compared to controls, the ADHD groups showed hypoactivation in motor/sensory cortices and hyperactivation in frontal pole and OFC during reward outcome. ADHD + SM also showed hyperactivation in frontal pole during neutral outcome. Moreover, ADHD + SM patients showed higher callous-unemotional (CU) traits that were positively correlated with putamen responses to reward anticipation. Our results show distinct condition-independent neural activation profile for ADHD + SM compared to ADHD-only and controls. Effects of comorbid substance misuse and variability of its prevalence across ADHD studies might have contributed to inconsistencies in ADHD literature. Contrasted with findings for reward-processing in SUD literature, results potentially suggest distinct underlying mechanisms for SUD subgroups with different characteristics, like antisocial/psychopathic traits.

Chromatin regulatory genes differentially interact in networks to facilitate distinct GAL1 activity and noise profiles.

Controlling chromatin state constitutes a major regulatory step in gene expression regulation across eukaryotes. While global cellular features or processes are naturally impacted by chromatin state alterations, little is known about how chromatin regulatory genes interact in networks to dictate downstream phenotypes. Using the activity of the canonical galactose network in yeast as a model, here, we measured the impact of the disruption of key chromatin regulatory genes on downstream gene expression, genetic noise and fitness. Using Trichostatin A and nicotinamide, we characterized how drug-based modulation of global histone deacetylase activity affected these phenotypes. Performing epistasis analysis, we discovered phenotype-specific genetic interaction networks of chromatin regulators. Our work provides comprehensive insights into how the galactose network activity is affected by protein interaction networks formed by chromatin regulators.

JAK/STAT Inhibition Targets TP53 altered Primary Human Acute Myeloid Leukemia Stem Cells

In acute myeloid leukemia (AML), the impact of genetic drivers on response to therapy and long-term survival has been well characterized. AML with complex cytogenetics and TP53 alterations (TP53Alt) is a poor-risk AML subtype that is largely insensitive to chemotherapy, modern targeted agents, and hematopoietic stem cell transplant leading to survival rates 0-10% at 1 year. In contrast, AML with favorable risk molecular features is highly sensitive to chemotherapy and confers survival rates of 50-70%. AML with intermediate risk molecular features can be responsive to chemotherapy and can be cured with hematopoietic stem cell transplant leading to overall survival rates of 30-60%. Leukemia stem cells (LSCs), the cells that recapitulate and propagate leukemia, are central to leukemia progression and relapse. Given the differences in chemo-sensitivity and clinical behavior of genetic subgroups of AML, we asked whether LSCs from poor risk AMLs exhibit distinct signaling activation profiles. We assembled a panel of 23 primary human AML samples with intermediate- and poor- risk genetics and used CyTOF (mass cytometry) to quantitatively measure the levels of immunophenotypic proteins and intracellular signaling molecules in each sample, at the single-cell level. We gated on CD34+CD123+CD3-CD19- cells (LSCs) and measured the level of intracellular signaling molecules within the LSCs of each sample. Notably, the intracellular signaling activation state of LSCs from each AML subtype was distinct; NFkB, pERK, p4EBP1, and pSTAT3 were uniquely upregulated in complex cytogenetics and TP53Alt LSCs, relative to LSCs from intermediate risk AML, suggesting that these signaling pathways may be important for LSC function in this AML subtype. Given that TP53Alt independently confer treatment resistance in AML, we focused on this genetic subgroup. We compared the gene expression profiles of TP53Alt and TP53-wild-type AML samples from the BEAT AML dataset (Tyner et al. Nature 2018) and found that the gene expression profiles of TP53Alt samples are enriched for gene sets representing JAK/STAT signaling, consistent with our CyTOF data, which identified activation of STAT3 in TP53Alt LSCs. A recent drug screen in AML demonstrated that a JAK1/2 kinase inhibitor, AZD1480, can reduce the in vitro viability of TP53-deleted AML cell lines (Nechiporuk et al. Ca Discovery 2019), but these effects were not tested in primary AML samples or on LSCs. Since LSCs confer treatment resistance, we investigated the effect of the AZD1480 on the LSC population in TP53Alt primary human AML samples. AZD1480 treatment abolished all colony formation in primary human TP53Alt AML samples (n=7, 6 replicates per sample, p&amp;lt;0.01). Treatment of these samples in liquid cultures led to a 50% reduction in LSC frequency. We used CyTOF to profile the intracellular signaling states of in vitro treated samples and found that AZD1480 attenuated pSTAT3, pSTAT5, p4EBP1, and NFkB in the LSCs of these samples. The mTOR/4EBp1 and NF༆B pathways have been implicated as drivers of self-renewal and LSC function in AML. Our data suggest that JAK/STAT inhibition may target these pathways in TP53Alt LSCs. These data demonstrate the unique signaling states of TP53Alt LSCs, relative to other LSCs, and show that inhibition of the JAK/STAT pathway specifically targets LSCs within human TP53Alt AML. Figure Disclosures No relevant conflicts of interest to declare.

Abstract 1847: Phenotypic evaluation and discrimination of clinical JAK inhibitors for myeloproliferative disorders

Abstract Small molecule inhibitors of Janus kinases (Jakinibs) represent a promising treatment for myeloproliferative disorders including polycythemia vera (PV), essential thrombocytosis (ET), and myelofibrosis (MF). Currently multiple JAK2 inhibitors (ruxolitinib, fedratinib, momelotinib, baricitinib) are either approved or in clinical development for the treatment of MF. The primary target of Jakinibs, the JAK-STAT pathway, plays a critical role in multiple cellular processes relevant for myelofibrosis, including survival, differentiation, and proliferation. However, all approved Jakinibs are reportedly promiscuous in that they inhibit kinases beyond the JAK family. Their overall clinical impact, therefore, reflects the sum of these target activities, as well as downstream secondary pharmacology relevant to both efficacy and safety. We evaluated these four Jakinibs using phenotypic profiling with the BioMAP® Diversity PLUS Panel to identify common versus differential activities. The BioMAP platform consists of human primary cell-based assay or systems designed to recapitulate key aspects of tissue and disease states. Distinct activity profiles were generated for each of the tested Jakinibs based on their impacts on 148 different biomarkers in 12 different model systems. Comparison of these profiles at concentrations relevant for clinical exposure levels revealed common activities including inhibition of T and B cell proliferation and decreased levels of inflammation and immune activation biomarkers. Together these activities represent a phenotypic signature related to shared primary JAK targets. In contrast, multiple differentiating activities were observed between the four drug profiles: baricitinib increased TNFα levels whereas momelotinib decreased TNFα in the LPS system modeling monocyte activation; fedratinib and momelotinib, but not ruxolitinib or baricitinib, inhibited endothelial cell proliferation; only momelotinib inhibited macrophage responses and decreased PGE2 levels. These data indicate that even within the specific JAK2 inhibitor drug class, individual entities have distinct modes of action relevant for clinical outcomes. Citation Format: Sharlene Velichko, Sheryl P. Denker, Alison O'Mahony. Phenotypic evaluation and discrimination of clinical JAK inhibitors for myeloproliferative disorders [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1847.

Latent profile analysis of physical activity and sedentary behavior with mortality risk: A 15-year follow-up.

By exploring multiple characteristics of physical activity and sedentary behavior (SB), different physical activity profiles could be obtained, which may be beneficial for health and targeted physical activity interventions. The aim of this study was to identify distinct physical activity profiles based on accelerometer-derived activity characteristics and to determine whether these profiles are associated with all-cause mortality. Eight hundred fifty-one participants (56% women, mean age: 53years) provided objectively assessed physical activity data using an ActiGraph accelerometer and were followed for 15years. Physical activity profiles were determined using latent profile analyses of 14 derived activity variables, resulting in that three profiles were identified: "Low Active" (n=147), "Average Active" (n=397), and "High Active" (n=307). "Low Active" was characterized by participants with low absolute, relative, and limited variation of time spent in physical activity, and high time spent in SB. "Average Active" had the most balanced movement behavior with values close to the mean for all activity variables. "High Active" was characterized by participants with high absolute, relative, and great variation of time spent in physical activity. Overall, a potentially non-linear pattern between multiple activity variables and all-cause mortality was found as "Low Active" was significantly (P<.05) positively associated with all-cause mortality, and no difference in mortality risk was found between "High Active" and "Average Active." Our data suggest that day-to-day variation in SB is not associated with all-cause mortality. The important message is to keep the overall time spent in SB low and replace this behavior with physical activity.

Distinct signals in medial and lateral VTA dopamine neurons modulate fear extinction at different times.

Dopamine (DA) neurons are to encode reward prediction error (RPE), in addition to other signals, such as salience. While RPE is known to support learning, the role of salience in learning remains less clear. To address this, we recorded and manipulated VTA DA neurons in mice during fear extinction. We applied deep learning to classify mouse freezing behavior, eliminating the need for human scoring. Our fiber photometry recordings showed DA neurons in medial and lateral VTA have distinct activity profiles during fear extinction: medial VTA activity more closely reflected RPE, while lateral VTA activity more closely reflected a salience-like signal. Optogenetic inhibition of DA neurons in either region slowed fear extinction, with the relevant time period for inhibition differing across regions. Our results indicate salience-like signals can have similar downstream consequences to RPE-like signals, although with different temporal dependencies.