A prolyl-isomerase mediates dopamine-dependent plasticity and cocaine motor sensitization.

Synaptic plasticity induced by cocaine and other drugs underlies addiction. Here we elucidate molecular events at synapses that cause this plasticity and the resulting behavioral response to cocaine in mice. In response to D1-dopamine-receptor signaling that is induced by drug administration, the glutamate-receptor protein metabotropic glutamate receptor 5 (mGluR5) is phosphorylated by microtubule-associated protein kinase (MAPK), which we show potentiates Pin1-mediated prolyl-isomerization of mGluR5 in instances where the product of an activity-dependent gene, Homer1a, is present to enable Pin1-mGluR5 interaction. These biochemical events potentiate N-methyl-D-aspartate receptor (NMDAR)-mediated currents that underlie synaptic plasticity and cocaine-evoked motor sensitization as tested in mice with relevant mutations. The findings elucidate how a coincidence of signals from the nucleus and the synapse can render mGluR5 accessible to activation with consequences for drug-induced dopamine responses and point to depotentiation at corticostriatal synapses as a possible therapeutic target for treating addiction.

Acetylation-mediated proteasomal degradation of core histones during DNA repair and spermatogenesis.

Histone acetylation plays critical roles in chromatin remodeling, DNA repair, and epigenetic regulation of gene expression, but the underlying mechanisms are unclear. Proteasomes usually catalyze ATP- and polyubiquitin-dependent proteolysis. Here, we show that the proteasomes containing the activator PA200 catalyze the polyubiquitin-independent degradation of histones. Most proteasomes in mammalian testes ("spermatoproteasomes") contain a spermatid/sperm-specific α subunit α4 s/PSMA8 and/or the catalytic ß subunits of immunoproteasomes in addition to PA200. Deletion of PA200 in mice abolishes acetylation-dependent degradation of somatic core histones during DNA double-strand breaks and delays core histone disappearance in elongated spermatids. Purified PA200 greatly promotes ATP-independent proteasomal degradation of the acetylated core histones, but not polyubiquitinated proteins. Furthermore, acetylation on histones is required for their binding to the bromodomain-like regions in PA200 and its yeast ortholog, Blm10. Thus, PA200/Blm10 specifically targets the core histones for acetylation-mediated degradation by proteasomes, providing mechanisms by which acetylation regulates histone degradation, DNA repair, and spermatogenesis.

Mycobacterium tuberculosis suppresses innate immunity by coopting the host ubiquitin system.

Mycobacterium tuberculosis PtpA, a secreted tyrosine phosphatase essential for tuberculosis pathogenicity, could be an ideal target for a drug against tuberculosis, but its active-site inhibitors lack selectivity over human phosphatases. Here we found that PtpA suppressed innate immunity dependent on pathways of the kinases Jnk and p38 and the transcription factor NF-κB by exploiting host ubiquitin. Binding of PtpA to ubiquitin via a region with no homology to human proteins activated it to dephosphorylate phosphorylated Jnk and p38, leading to suppression of innate immunity. Furthermore, the host adaptor TAB3 mediated NF-κB signaling by sensing ubiquitin chains, and PtpA blocked this process by competitively binding the ubiquitin-interacting domain of TAB3. Our findings reveal how pathogens subvert innate immunity by coopting host ubiquitin and suggest a potential tuberculosis treatment via targeting of ubiquitin-PtpA interfaces.

Noncanonical Wnt signaling maintains hematopoietic stem cells in the niche.

Wnt signaling is involved in self-renewal and maintenance of hematopoietic stem cells (HSCs); however, the particular role of noncanonical Wnt signaling in regulating HSCs in vivo is largely unknown. Here, we show Flamingo (Fmi) and Frizzled (Fz) 8, members of noncanonical Wnt signaling, both express in and functionally maintain quiescent long-term HSCs. Fmi regulates Fz8 distribution at the interface between HSCs and N-cadherin(+) osteoblasts (N-cad(+)OBs that enrich osteoprogenitors) in the niche. We further found that N-cad(+)OBs predominantly express noncanonical Wnt ligands and inhibitors of canonical Wnt signaling under homeostasis. Under stress, noncanonical Wnt signaling is attenuated and canonical Wnt signaling is enhanced in activation of HSCs. Mechanistically, noncanonical Wnt signaling mediated by Fz8 suppresses the Ca(2+)-NFAT- IFNγ pathway, directly or indirectly through the CDC42-CK1α complex and also antagonizes canonical Wnt signaling in HSCs. Taken together, our findings demonstrate that noncanonical Wnt signaling maintains quiescent long-term HSCs through Fmi and Fz8 interaction in the niche.

Efficient asymmetric diffusion channel in MnCo2O4 spinel for ammonium-ion batteries.

Transition metal oxides ion diffusion channels have been developed for ammonium-ion batteries (AIBs). However, the influence of microstructural features of diffusion channels on the storage and diffusion behavior of NH4+ is not fully unveiled. In this study, by using MnCo2O4 spinel as a model electrode, the asymmetric ion diffusion channels of MnCo2O4 have been regulated through bond length optimization strategy and investigate the effect of channel size on the diffusion process of NH4+. In addition, the reducing channel size significantly decreases NH4+ adsorption energy, thereby accelerating hydrogen bond formation/fracture kinetics and NH4+ reversible diffusion within 3D asymmetric channels. The optimized MnCo2O4 with oxygen vacancies/carbon nanotubes composite exhibits impressive specific capacity (219.2 mAh g-1 at 0.1 A g-1) and long-cycle stability. The full cell with 3,4,9,10-perylenetetracarboxylic diimide anode demonstrates a remarkable energy density of 52.3 Wh kg-1 and maintains 91.9% capacity after 500 cycles. This finding provides a unique approach for the development of cathode materials in AIBs.

Enhanced polyubiquitination of Shank3 and NMDA receptor in a mouse model of autism.

We have created a mouse genetic model that mimics a human mutation of Shank3 that deletes the C terminus and is associated with autism. Expressed as a single copy [Shank3(+/ΔC) mice], Shank3ΔC protein interacts with the wild-type (WT) gene product and results in >90% reduction of Shank3 at synapses. This "gain-of-function" phenotype is linked to increased polyubiquitination of WT Shank3 and its redistribution into proteasomes. Similarly, the NR1 subunit of the NMDA receptor is reduced at synapses with increased polyubiquitination. Assays of postsynaptic density proteins, spine morphology, and synapse number are unchanged in Shank3(+/ΔC) mice, but the amplitude of NMDAR responses is reduced together with reduced NMDAR-dependent LTP and LTD. Reciprocally, mGluR-dependent LTD is markedly enhanced. Shank3(+/ΔC) mice show behavioral deficits suggestive of autism and reduced NMDA receptor function. These studies reveal a mechanism distinct from haploinsufficiency by which mutations of Shank3 can evoke an autism-like disorder.

Targeting the Liver with Nucleic Acid Therapeutics for the Treatment of Systemic Diseases of Liver Origin.

Systemic diseases of liver origin (SDLO) are complex diseases in multiple organ systems, such as cardiovascular, musculoskeletal, endocrine, renal, respiratory, and sensory organ systems, caused by irregular liver metabolism and production of functional factors. Examples of such diseases discussed in this article include primary hyperoxaluria, familial hypercholesterolemia, acute hepatic porphyria, hereditary transthyretin amyloidosis, hemophilia, atherosclerotic cardiovascular diseases, α-1 antitrypsin deficiency-associated liver disease, and complement-mediated diseases. Nucleic acid therapeutics use nucleic acids and related compounds as therapeutic agents to alter gene expression for therapeutic purposes. The two most promising, fastest-growing classes of nucleic acid therapeutics are antisense oligonucleotides (ASOs) and small interfering RNAs (siRNAs). For each listed SDLO disease, this article discusses epidemiology, symptoms, genetic causes, current treatment options, and advantages and disadvantages of nucleic acid therapeutics by either ASO or siRNA drugs approved or under development. Furthermore, challenges and future perspectives on adverse drug reactions and toxicity of ASO and siRNA drugs for the treatment of SDLO diseases are also discussed. In summary, this review article will highlight the clinical advantages of nucleic acid therapeutics in targeting the liver for the treatment of SDLO diseases. SIGNIFICANCE STATEMENT: Systemic diseases of liver origin (SDLO) contain rare and common complex diseases caused by irregular functions of the liver. Nucleic acid therapeutics have shown promising clinical advantages to treat SDLO. This article aims to provide the most updated information on targeting the liver with antisense oligonucleotides and small interfering RNA drugs. The generated knowledge may stimulate further investigations in this growing field of new therapeutic entities for the treatment of SDLO, which currently have no or limited options for treatment.

Chinese Verbal Fluency Deficiency in Temporal Lobe Epilepsy with and without Hippocampal Sclerosis: A Multiscale Study.

To test a Chinese character version of the phonemic verbal fluency task in patients with temporal lobe epilepsy (TLE) and assess the verbal fluency deficiency pattern in TLE with and without hippocampal sclerosis, a cross-sectional study was conducted including 30 patients with TLE and hippocampal sclerosis (TLE-HS), 28 patients with TLE and without hippocampal sclerosis (TLE-NHS), and 29 demographically matched healthy controls (HC). Both sexes were enrolled. Participants finished a Chinese character verbal fluency (VFC) task during functional MRI. The activation/deactivation maps, functional connectivity, degree centrality, and community features of the left frontal and temporal regions were compared. A neural network classification model was applied to differentiate TLE-HS and TLE-NHS using functional statistics. The VFC scores were correlated with semantic fluency in HC while correlated with phonemic fluency in TLE-NHS. Activation and deactivation deficiency was observed in TLE-HS and TLE-NHS (p < 0.001, k ≥ 10). Functional connectivity, degree centrality, and community features of anterior inferior temporal gyri were impaired in TLE-HS and retained or even enhanced in TLE-NHS (p < 0.05, FDR-corrected). The functional connectivity was correlated with phonemic fluency (p < 0.05, FDR-corrected). The neural network classification reached an area under the curve of 0.90 in diagnosing hippocampal sclerosis. The VFC task is a Chinese phonemic verbal fluency task suitable for clinical application in TLE. During the VFC task, functional connectivity of phonemic circuits was impaired in TLE-HS and was enhanced in TLE-NHS, representing a compensative phonemic searching strategy applied by patients with TLE-NHS.

Crosstalk of MAP3K1 and EGFR signaling mediates gene-environment interactions that block developmental tissue closure.

Aberrant regulation of signal transduction pathways can adversely derail biological processes for tissue development. One such process is the embryonic eyelid closure that is dependent on the mitogen-activated protein kinase kinase kinase 1 (MAP3K1). Map3k1 KO in mice results in defective eyelid closure and an autosomal recessive eye-open at birth phenotype. We have shown that in utero exposure to dioxin, a persistent environmental toxicant, induces the same eye defect in Map3k1+/- heterozygous but not WT pups. Here, we explore the mechanisms of the Map3k1 (gene) and dioxin (environment) interactions (GxE) underlying defective eyelid closure. We show that, acting through the aryl hydrocarbon receptor, dioxin activates epidermal growth factor receptor signaling, which in turn depresses MAP3K1-dependent Jun N-terminal kinase (JNK) activity. The dioxin-mediated JNK repression is moderate but is exacerbated by Map3k1 heterozygosity. Therefore, dioxin exposed Map3k1+/- embryonic eyelids have a marked reduction of JNK activity, accelerated differentiation and impeded polarization in the epithelial cells. Knocking out Ahr or Egfr in eyelid epithelium attenuates the open-eye defects in dioxin-treated Map3k1+/- pups, whereas knockout of Jnk1 and S1pr that encodes the sphigosin-1-phosphate (S1P) receptors upstream of the MAP3K1-JNK pathway potentiates the dioxin toxicity. Our novel findings show that the crosstalk of aryl hydrocarbon receptor, epidermal growth factor receptor, and S1P-MAP3K1-JNK pathways determines the outcome of dioxin exposure. Thus, gene mutations targeting these pathways are potential risk factors for the toxicity of environmental chemicals.

Association of lipid-lowering drugs with risk of sarcopenia: a drug target mendelian randomization study and meta-analysis.

BACKGROUND: Lipid-lowering drugs are widely used among the elderly, with some studies suggesting links to muscle-related symptoms. However, the causality remains uncertain. METHODS: Using the Mendelian randomization (MR) approach, we assessed the causal effects of genetically proxied reduced low-density lipoprotein cholesterol (LDL-C) through inhibitions of hydroxy-methyl-glutaryl-CoA reductase (HMGCR), proprotein convertase subtilisin/kexin type 9 (PCSK9), and Niemann-Pick C1-like 1 (NPC1L1) on sarcopenia-related traits, including low hand grip strength, appendicular lean mass, and usual walking pace. A meta-analysis was conducted to combine the causal estimates from different consortiums. RESULTS: Using LDL-C pooled data predominantly from UK Biobank, genetically proxied inhibition of HMGCR was associated with higher appendicular lean mass (beta = 0.087, P = 7.56 × 10- 5) and slower walking pace (OR = 0.918, P = 6.06 × 10- 9). In contrast, inhibition of PCSK9 may reduce appendicular lean mass (beta = -0.050, P = 1.40 × 10- 3), while inhibition of NPC1L1 showed no causal impact on sarcopenia-related traits. These results were validated using LDL-C data from Global Lipids Genetics Consortium, indicating that HMGCR inhibition may increase appendicular lean mass (beta = 0.066, P = 2.17 × 10- 3) and decelerate walking pace (OR = 0.932, P = 1.43 × 10- 6), whereas PCSK9 inhibition could decrease appendicular lean mass (beta = -0.048, P = 1.69 × 10- 6). Meta-analysis further supported the robustness of these causal associations. CONCLUSIONS: Genetically proxied HMGCR inhibition may increase muscle mass but compromise muscle function, PCSK9 inhibition could result in reduced muscle mass, while NPC1L1 inhibition is not associated with sarcopenia-related traits and this class of drugs may serve as viable alternatives to sarcopenia individuals or those at an elevated risk.

Descending dopaminergic pathway facilitates itch signal processing via activating spinal GRPR+ neurons.

A11 dopaminergic neurons regulate somatosensory transduction by projecting from the diencephalon to the spinal cord, but the function of this descending projection in itch remained elusive. Here, we report that dopaminergic projection neurons from the A11 nucleus to the spinal dorsal horn (dopaminergicA11-SDH ) are activated by pruritogens. Inhibition of these neurons alleviates itch-induced scratching behaviors. Furthermore, chemogenetic inhibition of spinal dopamine receptor D1-expressing (DRD1+ ) neurons decreases acute or chronic itch-induced scratching. Mechanistically, spinal DRD1+ neurons are excitatory and mostly co-localize with gastrin-releasing peptide (GRP), an endogenous neuropeptide for itch. In addition, DRD1+ neurons form synapses with GRP receptor-expressing (GRPR+ ) neurons and activate these neurons via AMPA receptor (AMPAR). Finally, spontaneous itch and enhanced acute itch induced by activating spinal DRD1+ neurons are relieved by antagonists against AMPAR and GRPR. Thus, the descending dopaminergic pathway facilitates spinal itch transmission via activating DRD1+ neurons and releasing glutamate and GRP, which directly augments GRPR signaling. Interruption of this descending pathway may be used to treat chronic itch.

High-throughput screening identifies ibuprofen as an sEV PD-L1 inhibitor for synergistic cancer immunotherapy.

Programmed death-ligand 1 (PD-L1) on tumor-derived small extracellular vesicles (sEVs) limits therapeutic effectiveness by interacting with the PD-1 receptor on host immune cells. Targeting the secretion of sEV PD-L1 has emerged as a promising strategy to enhance immunotherapy. However, the lack of small-molecule inhibitors poses a challenge for clinical translation. In this study, we developed a target and phenotype dual-driven high-throughput screening strategy that combined virtual screening with nanoflow-based experimental verification. We identified ibuprofen (IBP) as a novel inhibitor that effectively targeted sEV PD-L1 secretion. IBP disrupted the biogenesis and secretion of PD-L1+ sEVs in tumor cells by physically interacting with a critical regulator of sEV biogenesis, hepatocyte growth factor-regulated tyrosine kinase substrate. Notably, the mechanism of action of IBP is distinct from its commonly known targets, cyclooxygenases. Administration of IBP stimulated antitumor immunity and enhanced the efficacy of anti-PD-1 therapy in melanoma and oral squamous cell carcinoma mouse models. To address potential adverse effects, we further developed an IBP gel for topical application, which demonstrated remarkable therapeutic efficacy when combined with anti-PD-1 treatment. The discovery of this specific small inhibitor provides a promising avenue for establishing durable, systemic antitumor immunity.

De novo variants in KCNJ3 are associated with early-onset epilepsy.

BACKGROUND: KCNJ3 encodes a subunit of G-protein-coupled inwardly rectifying potassium channels, which are important for cellular excitability and inhibitory neurotransmission. However, the genetic basis of KCNJ3 in epilepsy has not been determined. This study aimed to identify the pathogenic KCNJ3 variants in patients with epilepsy. METHODS: Trio exome sequencing was performed to determine potential variants of epilepsy. Individuals with KCNJ3 variants were recruited for this study. Detailed clinical information and genetic data were obtained and systematically reviewed. Whole-cell patch-clamp recordings were performed to evaluate the functional consequences of the identified variants. RESULTS: Two de novo missense variants (c.998T>C (p.Leu333Ser) and c.938G>A (p. Arg313Gln)) in KCNJ3 were identified in two unrelated families with epilepsy. The variants were absent from the gnomAD database and were assumed to be damaging or probably damaging using multiple bioinformatics tools. They were both located in the C-terminal domain. The amino acid residues were highly conserved among various species. Clinically, the seizures occurred at a young age and were under control after combined treatment. Electrophysiological analysis revealed that the KCNJ3 Leu333Ser and Arg313Gln variants significantly compromised the current activities and exhibited loss-of-function (LOF) effects. CONCLUSION: Our findings suggest that de novo LOF variants in KCNJ3 are associated with early-onset epilepsy. Genetic testing of KCNJ3 in patients with epilepsy may serve as a strategy for precision medicine.

GATOR2 complex-mediated amino acid signaling regulates brain myelination.

Amino acids are essential for cell growth and metabolism. Amino acid and growth factor signaling pathways coordinately regulate the mechanistic target of rapamycin complex 1 (mTORC1) kinase in cell growth and organ development. While major components of amino acid signaling mechanisms have been identified, their biological functions in organ development are unclear. We aimed to understand the functions of the critically positioned amino acid signaling complex GAP activity towards Rags 2 (GATOR2) in brain development. GATOR2 mediates amino acid signaling to mTORC1 by directly linking the amino acid sensors for arginine and leucine to downstream signaling complexes. Now, we report a role of GATOR2 in oligodendrocyte myelination in postnatal brain development. We show that the disruption of GATOR2 complex by genetic deletion of meiosis regulator for oocyte development (Mios, encoding a component of GATOR2) selectively impairs the formation of myelinating oligodendrocytes, thus brain myelination, without apparent effects on the formation of neurons and astrocytes. The loss of Mios impairs cell cycle progression of oligodendrocyte precursor cells, leading to their reduced proliferation and differentiation. Mios deletion manifests a cell type-dependent effect on mTORC1 in the brain, with oligodendroglial mTORC1 selectively affected. However, the role of Mios/GATOR2 in oligodendrocyte formation and myelination involves mTORC1-independent function. This study suggests that GATOR2 coordinates amino acid and growth factor signaling to regulate oligodendrocyte myelination.

Defect-Induced All-Solid-State Frustrated Lewis Pair on Metal-Organic Monolayer Accelerating Photocatalytic CO2 Reduction with H2O Vapor.

Understanding the structure-performance relationships of a frustrated Lewis pair (FLP) at the atomic level is key to yielding high efficiency in activating chemically "inert" molecules into value-added products. A sound strategy was developed herein through incorporating oxygen defects into a Zr-based metal-organic layer (Zr-MOL-D) and employing Lewis basic proximal surface hydroxyls for the in situ formation of solid heterogeneous FLP (Zr4-δ-VO-Zr-OH). Zr-MOL-D exhibits a superior CO2 to CO conversion rate of 49.4 µmol g-1 h-1 in water vapor without any sacrificing agent or photosensitizer, which is about 12 times higher than that of pure MOL (Zr-MOL-P), with extreme stability even after being placed for half a year. Theoretical and experimental results reveal that the introduction of FLP converts the process of the crucial intermediate COOH* from an endothermic reaction to an exothermic spontaneous reaction. This work is expected to provide new prospects for developing efficient MOL-based photocatalysts in FLP chemistry through a sound defect-engineering strategy.

KLHL21 suppresses gastric tumourigenesis via maintaining STAT3 signalling equilibrium in stomach homoeostasis.

OBJECTIVE: Precancerous metaplasia transition to dysplasia poses a risk for subsequent intestinal-type gastric adenocarcinoma. However, the molecular basis underlying the transformation from metaplastic to cancerous cells remains poorly understood. DESIGN: An integrated analysis of genes associated with metaplasia, dysplasia was conducted, verified and characterised in the gastric tissues of patients by single-cell RNA sequencing and immunostaining. Multiple mouse models, including homozygous conditional knockout Klhl21-floxed mice, were generated to investigate the role of Klhl21 deletion in stemness, DNA damage and tumour formation. Mass-spectrometry-based proteomics and ribosome sequencing were used to elucidate the underlying molecular mechanisms. RESULTS: Kelch-like protein 21 (KLHL21) expression progressively decreased in metaplasia, dysplasia and cancer. Genetic deletion of Klhl21 enhances the rapid proliferation of Mist1+ cells and their descendant cells. Klhl21 loss during metaplasia facilitates the recruitment of damaged cells into the cell cycle via STAT3 signalling. Increased STAT3 activity was confirmed in cancer cells lacking KLHL21, boosting self-renewal and tumourigenicity. Mechanistically, the loss of KLHL21 promotes PIK3CB mRNA translation by stabilising the PABPC1-eIF4G complex, subsequently causing STAT3 activation. Pharmacological STAT3 inhibition by TTI-101 elicited anticancer effects, effectively impeding the transition from metaplasia to dysplasia. In patients with gastric cancer, low levels of KLHL21 had a shorter survival rate and a worse response to adjuvant chemotherapy. CONCLUSIONS: Our findings highlighted that KLHL21 loss triggers STAT3 reactivation through PABPC1-mediated PIK3CB translational activation, and targeting STAT3 can reverse preneoplastic metaplasia in KLHL21-deficient stomachs.

Excitatory Projections from the Prefrontal Cortex to Nucleus Accumbens Core D1-MSNs and κ Opioid Receptor Modulate Itch-Related Scratching Behaviors.

Itch is an uncomfortable and complex sensation that elicits the desire to scratch. The nucleus accumbens (NAc) activity is important in driving sensation, motivation, and emotion. Excitatory afferents from the medial prefrontal cortex (mPFC), amygdala, and hippocampus are crucial in tuning the activity of dopamine receptor D1-expressing and D2-expressing medium spiny neurons (Drd1-MSN and Drd2-MSN) in the NAc. However, a cell-type and neural circuity-based mechanism of the NAc underlying acute itch remains unclear. We found that acute itch induced by compound 48/80 (C48/80) decreased the intrinsic membrane excitability in Drd1-MSNs, but not in Drd2-MSNs, in the NAc core of male mice. Chemogenetic activation of Drd1-MSNs alleviated C48/80-induced scratching behaviors but not itch-related anxiety-like behaviors. In addition, C48/80 enhanced the frequency of spontaneous EPSCs (sEPSCs) and reduced the paired-pulse ratio (PPR) of electrical stimulation-evoked EPSCs in Drd1-MSNs. Furthermore, C48/80 increased excitatory synaptic afferents to Drd1-MSNs from the mPFC, not from the basolateral amygdala (BLA) or ventral hippocampus (vHipp). Consistently, the intrinsic excitability of mPFC-NAc projecting pyramidal neurons was increased after C48/80 treatment. Chemogenetic inhibition of mPFC-NAc excitatory synaptic afferents relieved the scratching behaviors. Moreover, pharmacological activation of κ opioid receptor (KOR) in the NAc core suppressed C48/80-induced scratching behaviors, and the modulation of KOR activity in the NAc resulted in the changes of presynaptic excitatory inputs to Drd1-MSNs in C48/80-treated mice. Together, these results reveal the neural plasticity in synapses of NAc Drd1-MSNs from the mPFC underlying acute itch and indicate the modulatory role of the KOR in itch-related scratching behaviors.SIGNIFICANCE STATEMENT Itch stimuli cause strongly scratching desire and anxiety in patients. However, the related neural mechanisms remain largely unclear. In the present study, we demonstrated that the pruritogen compound 48/80 (C48/80) shapes the excitability of dopamine receptor D1-expressing medium spiny neurons (Drd1-MSNs) in the nucleus accumbens (NAc) core and the glutamatergic synaptic afferents from medial prefrontal cortex (mPFC) to these neurons. Chemogenetic activation of Drd1-MSNs or inhibition of mPFC-NAc excitatory synaptic afferents relieves the scratching behaviors. In addition, pharmacological activation of κ opioid receptor (KOR) in the NAc core alleviates C48/80-induced itch. Thus, targeting mPFC-NAc Drd1-MSNs or KOR may provide effective treatments for itch.

Novel dominant and recessive variants in human ROBO1 cause distinct neurodevelopmental defects through different mechanisms.

The Roundabout (Robo) receptors, located on growth cones of neurons, induce axon repulsion in response to the extracellular ligand Slit. The Robo family of proteins controls midline crossing of commissural neurons during development in flies. Mono- and bi-allelic variants in human ROBO1 (HGNC: 10249) have been associated with incomplete penetrance and variable expressivity for a breath of phenotypes, including neurodevelopmental defects such as strabismus, pituitary defects, intellectual impairment, as well as defects in heart and kidney. Here, we report two novel ROBO1 variants associated with very distinct phenotypes. A homozygous missense p.S1522L variant in three affected siblings with nystagmus; and a monoallelic de novo p.D422G variant in a proband who presented with early-onset epileptic encephalopathy. We modeled these variants in Drosophila and first generated a null allele by inserting a CRIMIC T2A-GAL4 in an intron. Flies that lack robo1 exhibit reduced viability but have very severe midline crossing defects in the central nervous system. The fly wild-type cDNA driven by T2A-Gal4 partially rescues both defects. Overexpression of the human reference ROBO1 with T2A-GAL4 is toxic and reduces viability, whereas the recessive p.S1522L variant is less toxic, suggesting that it is a partial loss-of-function allele. In contrast, the dominant variant in fly robo1 (p.D413G) affects protein localization, impairs axonal guidance activity and induces mild phototransduction defects, suggesting that it is a neomorphic allele. In summary, our studies expand the phenotypic spectrum associated with ROBO1 variant alleles.

Dynamic genomic changes in methotrexate-resistant human cancer cell lines beyond DHFR amplification suggest potential new targets for preventing drug resistance.

BACKGROUND: Although DHFR gene amplification has long been known as a major mechanism for methotrexate (MTX) resistance in cancer, the early changes and detailed development of the resistance are not yet fully understood. METHODS: We performed genomic, transcriptional and proteomic analyses of human colon cancer cells with sequentially increasing levels of MTX-resistance. RESULTS: The genomic amplification evolved in three phases (pre-amplification, homogenously staining region (HSR) and extrachromosomal DNA (ecDNA)). We confirm that genomic amplification and increased expression of DHFR, with formation of HSRs and especially ecDNAs, is the major driver of resistance. However, DHFR did not play a detectable role in the early phase. In the late phase (ecDNA), increase in FAM151B protein level may also have an important role by decreasing sensitivity to MTX. In addition, although MSH3 and ZFYVE16 may be subject to different posttranscriptional regulations and therefore protein expressions are decreased in ecDNA stages compared to HSR stages, they still play important roles in MTX resistance. CONCLUSION: The study provides a detailed evolutionary trajectory of MTX-resistance and identifies new targets, especially ecDNAs, which could help to prevent drug resistance. It also presents a proof-of-principal approach which could be applied to other cancer drug resistance studies.

PdmIRD: missense variants pathogenicity prediction for inherited retinal diseases in a disease-specific manner.

Accurate discrimination of pathogenic and nonpathogenic variation remains an enormous challenge in clinical genetic testing of inherited retinal diseases (IRDs) patients. Computational methods for predicting variant pathogenicity are the main solutions for this dilemma. The majority of the state-of-the-art variant pathogenicity prediction tools disregard the differences in characteristics among different genes and treat all types of mutations equally. Since missense variants are the most common type of variation in the coding region of the human genome, we developed a novel missense mutation pathogenicity prediction tool, named Prediction of Deleterious Missense Mutation for IRDs (PdmIRD) in this study. PdmIRD was tailored for IRDs-related genes and constructed with the conditional random forest model. Population frequencies and a newly available prediction tool were incorporated into PdmIRD to improve the performance of the model. The evaluation of PdmIRD demonstrated its superior performance over nonspecific tools (areas under the curves, 0.984 and 0.910) and an existing eye abnormalities-specific tool (areas under the curves, 0.975 and 0.891). We also demonstrated the submodel that used a smaller gene panel further slightly improved performance. Our study provides evidence that a disease-specific model can enhance the prediction of missense mutation pathogenicity, especially when new and important features are considered. Additionally, this study provides guidance for exploring the characteristics and functions of the mutated proteins in a greater number of Mendelian disorders.