Jingfeng Zhou.

Interview with Jingfeng Zhou, who studies how environmental factors impact associative learning and decision-making at the Chinese Institute for Brain Research, Beijing.

Hippocampal and orbitofrontal neurons contribute to complementary aspects of associative structure.

The ability to establish associations between environmental stimuli is fundamental for higher-order brain functions like state inference and generalization. Both the hippocampus and orbitofrontal cortex (OFC) play pivotal roles in this, demonstrating complex neural activity changes after associative learning. However, how precisely they contribute to representing learned associations remains unclear. Here, we train head-restrained mice to learn four 'odor-outcome' sequence pairs composed of several task variables-the past and current odor cues, sequence structure of 'cue-outcome' arrangement, and the expected outcome; and perform calcium imaging from these mice throughout learning. Sequence-splitting signals that distinguish between paired sequences are detected in both brain regions, reflecting associative memory formation. Critically, we uncover differential contents in represented associations by examining, in each area, how these task variables affect splitting signal generalization between sequence pairs. Specifically, the hippocampal splitting signals are influenced by the combination of past and current cues that define a particular sensory experience. In contrast, the OFC splitting signals are similar between sequence pairs that share the same sequence structure and expected outcome. These findings suggest that the hippocampus and OFC uniquely and complementarily organize the acquired associative structure.

Neratinib impairs function of m6A recognition on AML1-ETO pre-mRNA and induces differentiation of t (8;21) AML cells by targeting HNRNPA3.

Acute myeloid leukemia (AML) is frequently linked to genetic abnormalities, with the t (8; 21) translocation, resulting in the production of a fusion oncoprotein AML1-ETO (AE), being a prevalent occurrence. This protein plays a pivotal role in t (8; 21) AML's onset, advancement, and recurrence, making it a therapeutic target. However, the development of drug molecules targeting AML1-ETO are markedly insufficient, especially used in clinical treatment. In this study, it was uncovered that Neratinib could significantly downregulate AML1-ETO protein level, subsequently promoting differentiation of t (8; 21) AML cells. Based on "differentiated active" probes, Neratinib was identified as a functional inhibitor against HNRNPA3 through covalent binding. The further studies demonstrated that HNRNPA3 function as a putative m6A reader responsible for recognizing and regulating the alternative splicing of AML-ETO pre-mRNA. These findings not only contribute to a novel insight to the mechanism governing post-transcriptional modification of AML1-ETO transcript, but also suggest that Neratinib would be promising therapeutic potential for t (8; 21) AML treatment.

Event-specific and persistent representations for contextual states in orbitofrontal neurons.

Flexible and context-dependent behaviors require animals, including humans, to identify their current contextual state for proper rules to apply, especially when information that defines these states is partially observable. Depending on behavioral needs, contextual states usually persist for prolonged periods and across other events, including sensory stimuli, actions, and rewards, highlighting prominent challenges of holding a reliable state representation. The orbitofrontal cortex (OFC) is crucial in behaviors requiring the identification of the current context (e.g., reversal learning); however, how single units in the OFC accomplish this function has not been assessed. Do they maintain such information persistently, in separate populations from those responding phasically to events within a task, or is contextual information dynamic and embedded in these phasic responses? Here, we investigated this question by recording single units from OFC in rats performing a task that required them to identify the current contextual state related to estimated proximity to future reward with distracting olfactory cues. We found that while some OFC neurons encode contextual states, most change their selectivity upon the transition of task events. Nevertheless, despite dynamic activities in single neurons, the neural populations maintain persistent representations regarding current contextual states within particular neural subspaces.

A novel AML1-ETO/FTO positive feedback loop promotes leukemogenesis and Ara-C resistance via stabilizing IGFBP2 in t(8;21) acute myeloid leukemia.

BACKGROUND: t(8;21)(q22;q22) is one of the most frequent chromosomal abnormalities in acute myeloid leukemia (AML), leading to the generation of the fusion protein AML1-ETO. Despite t(8;21) AML being considered as a subtype with a favorable prognosis, approximately 30-50% of patients experience drug resistance and subsequent relapse. N6-methyladenosine (m6A) is demonstrated to be involved in the development of AML. However, the regulatory mechanisms between AML1-ETO and m6A-related enzymes and the roles of dysregulated m6A modifications in the t(8;21)-leukemogenesis and chemoresistance remain elusive. METHODS: Chromatin immunoprecipitation, dual-luciferase reporter assay, m6A-qPCR, RNA immunoprecipitation, and RNA stability assay were used to investigate a regulatory loop between AML1-ETO and FTO, an m6A demethylase. Gain- and loss-of-function experiments both in vitro and in vivo were further performed. Transcriptome-wide RNA sequencing and m6A sequencing were conducted to identify the potential targets of FTO. RESULTS: Here we show that FTO is highly expressed in t(8;21) AML, especially in patients with primary refractory disease. The expression of FTO is positively correlated with AML1-ETO, which is attributed to a positive regulatory loop between the AML1-ETO and FTO. Mechanistically, AML1-ETO upregulates FTO expression through inhibiting the transcriptional repression of FTO mediated by PU.1. Meanwhile, FTO promotes the expression of AML1-ETO by inhibiting YTHDF2-mediated AML1-ETO mRNA decay. Inactivation of FTO significantly suppresses cell proliferation, promotes cell differentiation and renders resistant t(8;21) AML cells sensitive to Ara-C. FTO exerts functions by regulating its mRNA targets, especially IGFBP2, in an m6A-dependent manner. Regain of Ara-C tolerance is observed when IGFBP2 is overexpressed in FTO-knockdown t(8;21) AML cells. CONCLUSION: Our work reveals a therapeutic potential of targeting AML1-ETO/FTO/IGFBP2 minicircuitry in the treatment for t(8;21) patients with resistance to Ara-C.

DNA methylation landscape reveals GNAS as a decitabine-responsive marker in patients with acute myeloid leukemia.

BACKGROUND: The demethylation agent decitabine (DAC) is a pivotal non-intensive alternative treatment for acute myeloid leukemia (AML). However, patient responses to DAC are highly variable, and predictive biomarkers are warranted. Herein, the DNA methylation landscape of patients treated with a DAC-based combination regimen was compared with that of patients treated with standard chemotherapy to develop a molecular approach for predicting clinical response to DAC. METHODS: Twenty-five non-M3 AML patients were enrolled and subjected to DNA methylation sequencing and profiling to identify differentially methylated regions (DMRs) and genes of interest. Moreover, the effects of a DAC-based regimen on apoptosis and gene expression were explored using Kasumi-1 and K562 cells. RESULTS: Overall, we identified 541 DMRs that were specifically responsive to DAC, among which 172 DMRs showed hypomethylation patterns upon treatment and were aligned with the promoter regions of 182 genes. In particular, GNAS was identified as a critical DAC-responsive gene, with in vitro GNAS downregulation leading to reduced cell apoptosis induced by DAC and cytarabine combo treatment. CONCLUSIONS: We found that GNAS is a DAC-sensitive gene in AML and may serve as a prognostic biomarker to assess the responsiveness of patients with AML to DAC-based therapy.

DNA methylation landscape reveals LIN7A as a decitabine-responsive marker in patients with t(8;21) acute myeloid leukemia.

BACKGROUND: Despite its inconsistent response rate, decitabine, a demethylating agent, is often used as a non-intensive alternative therapeutic agent for acute myeloid leukemia (AML). It has been reported that relapsed/refractory AML patients with t(8;21) translocation achieved better clinical outcomes with a decitabine-based combination regimen than other AML subtypes; however, the mechanisms underlying this phenomenon remain unknown. Herein, the DNA methylation landscape of de novo patients with the t(8;21) translocation was compared with that of patients without the translocation. Moreover, the methylation changes induced by decitabine-based combination regimens in de novo/complete remission paired samples were investigated to elucidate the mechanisms underlying the better responses observed in t(8;21) AML patients treated with decitabine. METHODS: Thirty-three bone marrow samples from 28 non-M3 AML patients were subjected to DNA methylation sequencing to identify the differentially methylated regions and genes of interest. TCGA-AML Genome Atlas-AML transcriptome dataset was used to identify decitabine-sensitive genes that were downregulated following exposure to a decitabine-based regimen. In addition, the effect of decitabine-sensitive gene on cell apoptosis was examined in vitro using Kasumi-1 and SKNO-1 cells. RESULTS: A total of 1377 differentially methylated regions that specifically responsive to decitabine in t(8;21) AML were identified, of which 210 showed hypomethylation patterns following decitabine treatment aligned with the promoter regions of 72 genes. And the methylation-silencing genes, LIN7A, CEBPA, BASP1, and EMB were identified as critical decitabine-sensitive genes in t(8;21) AML. Moreover, AML patients with hypermethylated LIN7A and reduced LIN7A expression had poor clinical outcomes. Meanwhile, the downregulation of LIN7A inhibited decitabine/cytarabine combination treatment-induced apoptosis in t(8;21) AML cells in vitro. CONCLUSION: The findings of this study suggest that LIN7A is a decitabine-sensitive gene in t(8;21) AML patients that may serve as a prognostic biomarker for decitabine-based therapy.

CDK12 orchestrates super-enhancer-associated CCDC137 transcription to direct hepatic metastasis in colorectal cancer.

BACKGROUND: Hepatic metastasis is the primary and direct cause of death in individuals with colorectal cancer (CRC) attribute to lack of effective therapeutic targets. The present study aimed to identify potential druggable candidate targets for patients with liver metastatic CRC. METHODS: The transcriptional profiles of super-enhancers (SEs) in primary and liver metastatic CRC were evaluated in publicly accessible CRC datasets. Immunohistochemistry of human CRC tissues was conducted to determine the expression level of CDK12. Cellular proliferation, survival and stemness were examined upon CDK12 inhibition by shCDK12 or a selective CDK12 inhibitor named SR-4835 with multiple in vitro and in vivo assays. RNA sequencing and bioinformatics analyses were carried out to investigate the mechanisms of CDK12 inhibition in CRC cells. RESULTS: We identified CDK12 as a driver gene for direct hepatic metastasis in CRC. Suppression of CDK12 led to robust inhibition of proliferation, survival and stemness. Mechanistically, CDK12 intervention preferentially repressed the transcription of SE-associated genes. Integration of the SE landscape and RNA sequencing, BCL2L1 and CCDC137 were identified as SE-associated oncogenic genes to strengthen the abilities of cellular survival, proliferation and stemness, eventually increasing liver metastasis of CRC. CONCLUSIONS: Our data highlight the potential of CDK12 and SE-associated oncogenic transcripts as therapeutic targets for patients with liver metastatic CRC.

Laser derusting on low carbon steel surface based on coordinated application of machine vision and laser-induced breakdown spectroscopy.

Online monitoring and closed-loop control are essential to accurately remove the rust layer and effectively avoid damage to the substrate. A collaborative utilization of machine vision and laser-induced breakdown spectroscopy (LIBS) to monitor and control the laser derusting process on Q235B steel is reported. The optimum overlap ratio of 50% is obtained by using machine vision. Monitoring derusting with different thicknesses relies on the Pearson correlation coefficient of the LIBS spectrum between the rust layer and substrate. By developing a collaborative monitoring and control system on LabVIEW, the functions of date acquisition, coordinate transformation, and data calculation are realized to automatically control the laser derusting process on rusty steel in a large area. The cooperation of two methods can achieve high-quality laser derusting with a derusting degree of 99.1%, roughness of 1.45 µm, and extremely low oxygen content on the surface, which verifies the accuracy and practicability of the developed monitoring system. Moreover, the potentiodynamic polarization curves demonstrate that the performance of the corrosion resistance of the Q235B steel is effectively improved after laser derusting.

Dynamic Event-Triggered Predictive Control for Interval Type-2 Fuzzy Systems with Imperfect Premise Matching.

This paper investigates the dynamic event-triggered predictive control problem of interval type-2 (IT2) fuzzy systems with imperfect premise matching. First, an IT2 fuzzy systems model is proposed, including a dynamic event-triggered mechanism, which can save limited network resources by reducing the number of data packets transmitted, and a predictive controller, which can predict the state of the system between the two successful transmitted instants to deal with unreliable communication networks. Then, according to the Lyapunov stability theory and imperfect premise matching method, sufficient conditions for system stabilization and the controller gain are obtained. Finally, the validity of the proposed method is demonstrated by the numerical examples.

Super-enhancer landscape reveals leukemia stem cell reliance on X-box binding protein 1 as a therapeutic vulnerability.

Relapse of patients with chronic myelogenous leukemia (CML) may occur at least partially because leukemia stem cells (LSCs) lack sensitivity to tyrosine kinase inhibitors (TKIs) such as imatinib. The precise regulation of LSC stemness is incompletely understood. Given that traits of LSCs are subject to epigenetic regulation, we hypothesized that LSCs might be dependent on continuous active transcription of genes associated with super-enhancers (SEs), which might, in turn, suggest an opportunity for intervention. In this study, we tested this hypothesis and delineated the SE landscape in LSCs from patients with CML. Disruption of the SE-associated gene transcription by THZ1, a covalent cyclin-dependent kinase 7 (CDK7) inhibitor, efficiently eradicated LSCs in retroviral BCR-ABL­driven CML mice while sparing normal hematopoietic stem cells. Furthermore, we found that X-box binding protein 1 (XBP1), a substrate of mRNA-splicing endonuclease IRE1α in the unfolded protein response pathway, was an SE-associated oncogene in LSCs. Knockdown of XBP1 reduced survival and self-renewal capacity in primary CML CD34+ cells and eradicated LSCs in CML mice. Selectively blocking generation of the spliced form of Xbp1 by hematopoietic cell­specific Ire1 conditional knockout suppressed the progression of CML and impaired the leukemogenesis of LSCs in CML mice. Overall, we identified an epigenetic transcriptional program in LSCs, adding to evidence for the theory of "oncogene addiction" and suggesting a potential targeting strategy for CML.

Prospective representations in rat orbitofrontal ensembles.

The orbitofrontal cortex (OFC) has been proposed to encode expected outcomes, which is thought to be important for outcome-directed behavior. However, such neural encoding can also often be explained by the recall of information about the recent past. To dissociate the retrospective and prospective aspects of encoding in the OFC, we designed a nonspatial, continuous, alternating odor-sequence task that mimicked a continuous T-maze. The task consisted of two alternating sequences of four odor-guided trials (2 sequences × 4 positions). In each trial, rats were asked to make a "go" or "no-go" action based on a fixed odor-reward contingency. Odors at both the first and last positions were distinct across the two sequences, such that they resembled unique paths in the past and future, respectively; odors at positions in between were the same and thus resembled a common path. We trained classifiers using neural activity to distinguish between either sequences or positions and asked whether the neural activity patterns in the common path were more like the ones in the past or the future. We found a proximal prospective code for sequence information as well as a distal perspective code for positional information, the latter of which was closely associated with rats' ability to predict future outcomes. This study demonstrates a behaviorally relevant predictive code in rat OFC. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Activation of transmembrane receptor tyrosine kinase DDR1-STAT3 cascade by extracellular matrix remodeling promotes liver metastatic colonization in uveal melanoma.

Colonization is believed a rate-limiting step of metastasis cascade. However, its underlying mechanism is not well understood. Uveal melanoma (UM), which is featured with single organ liver metastasis, may provide a simplified model for realizing the complicated colonization process. Because DDR1 was identified to be overexpressed in UM cell lines and specimens, and abundant pathological deposition of extracellular matrix collagen, a type of DDR1 ligand, was noted in the microenvironment of liver in metastatic patients with UM, we postulated the hypothesis that DDR1 and its ligand might ignite the interaction between UM cells and their surrounding niche of liver thereby conferring strengthened survival, proliferation, stemness and eventually promoting metastatic colonization in liver. We tested this hypothesis and found that DDR1 promoted these malignant cellular phenotypes and facilitated metastatic colonization of UM in liver. Mechanistically, UM cells secreted TGF-ß1 which induced quiescent hepatic stellate cells (qHSCs) into activated HSCs (aHSCs) which secreted collagen type I. Such a remodeling of extracellular matrix, in turn, activated DDR1, strengthening survival through upregulating STAT3-dependent Mcl-1 expression, enhancing stemness via upregulating STAT3-dependent SOX2, and promoting clonogenicity in cancer cells. Targeting DDR1 by using 7rh, a specific inhibitor, repressed proliferation and survival in vitro and in vivo outgrowth. More importantly, targeting cancer cells by pharmacological inactivation of DDR1 or targeting microenvironmental TGF-ß1-collagen I loop exhibited a prominent anti-metastasis effect in mice. In conclusion, targeting DDR1 signaling and TGF-ß signaling may be a novel approach to diminish hepatic metastasis in UM.

Is the core function of orbitofrontal cortex to signal values or make predictions?

One dominant hypothesis about the function of the orbitofrontal cortex (OFC) is that the OFC signals the subjective values of possible outcomes to other brain areas for learning and decision making. This popular view generally neglects the fact that OFC is not necessary for simple value-based behavior (i.e., when values have been directly experienced). An alternative, emerging view suggests that OFC plays a more general role in representing structural information about the task or environment, derived from prior experience, and relevant to predicting behavioral outcomes, such as value. From this perspective, value signaling is simply one derivative of the core underlying function of OFC. New data in favor of both views have been accumulating rapidly. Here we review these new data in discussing the relative merits of these two ideas.

[A Review of the Roles of Endoplasmic Reticulum Stress in Cancer Cell Metastasis].

Metastasis is a multistep and low-efficiency biological process driven by acquisition of genetic and/or epigenetic alterations within tumor cells. These evolutionary alterations enable tumor cells to thrive in the inhospitable microenvironment they encounter in the process of metastasis and eventually lead to macroscopic metastases in distant organs. The unfolded protein response (UPR) induced by endoplasmic reticulum (ER) stress is one of the most important mechanisms regulating cellular adaptation to an adverse microenvironment. UPR is involved in all stages of metastasis, playing an important role in tumor cell growth, survival, and differentiation and the process of maintaining protein hemostasis. Sustained activation of ER stress sensors endows tumor cells with better epithelial-mesenchymal transition (EMT), survival, immune escape, angiogenesis, cellular adhesion, dormancy-to reactivation capacity in the process of metastasis. Here, we discussed the role of UPR in regulating the above-mentioned abilities of tumor cells during metastasis, providing a reference for development of new targets for the treatment of tumor metastasis.UPR in regulating the above-mentioned characteristics and mechanisms of tumor cells during metastasis, providing a reference for development of new targets for the treatment of tumor metastasis.

Evolving schema representations in orbitofrontal ensembles during learning.

How do we learn about what to learn about? Specifically, how do the neural elements in our brain generalize what has been learned in one situation to recognize the common structure of-and speed learning in-other, similar situations? We know this happens because we become better at solving new problems-learning and deploying schemas1-5-through experience. However, we have little insight into this process. Here we show that using prior knowledge to facilitate learning is accompanied by the evolution of a neural schema in the orbitofrontal cortex. Single units were recorded from rats deploying a schema to learn a succession of odour-sequence problems. With learning, orbitofrontal cortex ensembles converged onto a low-dimensional neural code across both problems and subjects; this neural code represented the common structure of the problems and its evolution accelerated across their learning. These results demonstrate the formation and use of a schema in a prefrontal brain region to support a complex cognitive operation. Our results not only reveal a role for the orbitofrontal cortex in learning but also have implications for using ensemble analyses to tap into complex cognitive functions.

Processing in Lateral Orbitofrontal Cortex Is Required to Estimate Subjective Preference during Initial, but Not Established, Economic Choice.

The orbitofrontal cortex (OFC) is proposed to be critical to economic decision making. Yet one can inactivate OFC without affecting well-practiced choices. One possible explanation of this lack of effect is that well-practiced decisions are codified into habits or configural-based policies not normally thought to require OFC. Here, we tested this idea by training rats to choose between different pellet pairs across a set of standard offers and then inactivating OFC subregions during choices between novel offers of previously experienced pairs or between novel pairs of previously experienced pellets. Contrary to expectations, controls performed as well on novel as experienced offers yet had difficulty initially estimating their subjective preference on novel pairs, difficulty exacerbated by lateral OFC inactivation. This pattern of results indicates that established economic choice reflects the use of an underlying model or goods space and that lateral OFC is only required for normal behavior when the established framework must incorporate new information.

Erratum: The antihelminthic drug niclosamide effectively inhibits the malignant phenotypes of uveal melanoma in vitro and in vivo: Erratum.

[This corrects the article DOI: 10.7150/thno.17451.].

Rapid Analysis of Four Amphetamines in Urine by Self-Made Pipette-Tip Solid-Phase Extraction Followed by GC-MS/MS.

A simple and rapid pipette-tip solid-phase extraction (PT-SPE) procedure with derivatization prior to gas chromatography triple quadrupole mass spectrometry analysis is developed for the simultaneous determination of amphetamine (AMP), methamphetamine (MA), 3,4-methylenedioxyamphetamine (MDA) and 3,4-methylenedioxymethamphetamine (MDMA) in urine samples. The PT-SPE procedure using self-made sorbent could extract drugs within 6 min from 100-µL urine samples, requiring low solvent-consumption (<2.0 mL). Besides, the self-made pipette tip could be reused at least five times. Under optimized conditions, the recoveries of four amphetamines at spiked levels (low, medium and high) ranged from 87.7 to 110.4%, with relative standard deviations < 9.5%. The limit of detections and limit of quantifications for AMP, MA, MDA and MDMA were in the range of 2.52-8.25 ng⋅mL-1 and 8.4-27.5 ng⋅mL-1, respectively. Validation results show that the proposed method is suitable for the quantitation of amphetamines and has been successfully applied in the urine samples of suspected drug abusers.