Tropomyosin 2 Regulates Tumor Cell Proliferation, Immune Suppression, and Activation of the JNK Signaling Pathway in Colitis-Associated Cancer (CAC).

BACKGROUND: Tropomyosin 2 (TPM2) has been linked to the advancement of various tumor types, exhibiting distinct impacts on tumor progression. In our investigation, the primary objective was to identify the potential involvement of TPM2 in the development of colitis-associated cancer (CAC) using a mice model. METHODS: This study used lentiviral vector complex for TPM2 knockdown (sh-TPM2) and the corresponding negative control lentiviral vector complex (sh-NC) for genetic interference in mice. CAC was induced in mice using azoxymethane (AOM) and dextran sulfate sodium salt (DSS). This study included 6 groups of mice models: Control, Control+sh-NC, Control+sh-TPM2, CAC, CAC+sh-NC, and CAC+sh-TPM2. Subsequently, colon tissues were collected and assessed using quantitative reverse transcription-polymerase chain reaction (qRT-PCR) for TPM2 mRNA levels and flow cytometry for infiltrating immune cells. Tumor number, size, and weight within colon tissues from CAC mice were measured and recorded. The hematoxylin-eosin staining was used for observing tissue pathology changes. The intestinal epithelial cells (IECs) were isolated and analyzed for cell proliferation. This analysis included examining the levels of 5-bromo-2-deoxyuridine (BrdU) and Ki-67 using immunohistochemistry. Additionally, the mRNA levels of proliferating cell nuclear antigen (PCNA) and Ki-67 were detected by qRT-PCR. This study also investigated the activation of the c-Jun N-terminal kinase (JNK) pathway using western blot analysis. Immunogenicity analyses were conducted using immunohistochemistry for F4/80 and flow cytometry. RESULTS: In 8-week-old mice, AOM injections and three cycles of DSS treatment induced TPM2 upregulation in tumor tissues compared to normal tissues (p < 0.05). Fluorescence-activated cell sorting (FACS)-isolated lamina CAC adenomas revealed macrophages and dendritic cells as primary TPM2 contributors (p < 0.001). Lentiviral TPM2 gene knockdown significantly reduced tumor numbers and sizes in CAC mice (p < 0.01, and p < 0.001), without invasive cancer cells. TPM2 suppression resulted in decreased IEC proliferation (p < 0.001) and reduced PCNA and Ki-67 expression (p < 0.05). Western blot analysis indicated reduced JNK pathway activation in TPM2-knockdown CAC mice (p < 0.05, p < 0.001). TPM2 knockdown decreased tumor-associated macrophage infiltration (p < 0.01) and increased CD3+ and CD8+ T cells (p < 0.01, and p < 0.001), with increased levels of regulator of inflammatory cytokines (CD44+, CD107a+) (p < 0.01, and p < 0.001), decreased levels of PD-1+ and anti-inflammatory factor (IL10+) (p < 0.01, and p < 0.001). CONCLUSIONS: Our results demonstrated that TPM2 knockdown suppressed the proliferation of CAC IECs, enhanced immune suppression on CAC IECs, and inhibited the JNK signaling pathway within the framework of CAC. These findings suggest TPM2 can serve as a potential therapeutic target for CAC treatment.

IMF: Interpretable Multi-Hop Forecasting on Temporal Knowledge Graphs.

Temporal knowledge graphs (KGs) have recently attracted increasing attention. The temporal KG forecasting task, which plays a crucial role in such applications as event prediction, predicts future links based on historical facts. However, current studies pay scant attention to the following two aspects. First, the interpretability of current models is manifested in providing reasoning paths, which is an essential property of path-based models. However, the comparison of reasoning paths in these models is operated in a black-box fashion. Moreover, contemporary models utilize separate networks to evaluate paths at different hops. Although the network for each hop has the same architecture, each network achieves different parameters for better performance. Different parameters cause identical semantics to have different scores, so models cannot measure identical semantics at different hops equally. Inspired by the observation that reasoning based on multi-hop paths is akin to answering questions step by step, this paper designs an Interpretable Multi-Hop Reasoning (IMR) framework based on consistent basic models for temporal KG forecasting. IMR transforms reasoning based on path searching into stepwise question answering. In addition, IMR develops three indicators according to the characteristics of temporal KGs and reasoning paths: the question matching degree, answer completion level, and path confidence. IMR can uniformly integrate paths of different hops according to the same criteria; IMR can provide the reasoning paths similarly to other interpretable models and further explain the basis for path comparison. We instantiate the framework based on common embedding models such as TransE, RotatE, and ComplEx. While being more explainable, these instantiated models achieve state-of-the-art performance against previous models on four baseline datasets.

Single amino acid variation in MAB21L1 is dominantly associated with congenital eye defects.

BACKGROUND: Diagnosis of a genetic disease and determination of the causative molecular lesion rely on the availability of the disease-associated pedigrees. Microphthalmia is a congenital eye defect due to an insufficiently developed visual system; its prevalence is 1-3 in 10 000 live births. OBJECTIVE: We analysed a pedigree exhibiting autosomal dominant inheritance of microphthalmia to determine the genetic lesion; used AlphaFold2 to predict the changes in the protein's 3-Dimensional structure; and compared wild-type and variant proteins in cultured cells or Drosophila model was used to explore the cellular or developmental function of the encoded product. RESULTS: We identified a novel missense variation, F52L, in MAB21L1 that is absent in population databases and present exclusively in the individuals diagnosed with microphthalmia in this pedigree. Common structural changes were predicted for the disease-associated variants clustered at amino acids 49-52, and these variant products were also predominantly trapped in the cytoplasm of cultured human lens epithelia. To recapitulate its dominant effect in development, we expressed the Drosophila homologue corresponding to MAB21L1F52L and caused malformation of sensory organs. CONCLUSION: Mutations at the residues 49-52 of MAB21L1 compromise eye development. We recommend including MAB21L1 in the genetic testing panel for congenital eye disorders.

A Convolutional Neural Network and Graph Convolutional Network Based Framework for Classification of Breast Histopathological Images.

The spatial correlation among different tissue components is an essential characteristic for diagnosis of breast cancers based on histopathological images. Graph convolutional network (GCN) can effectively capture this spatial feature representation, and has been successfully applied to the histopathological image based computer-aided diagnosis (CAD). However, the current GCN-based approaches need complicated image preprocessing for graph construction. In this work, we propose a novel CAD framework for classification of breast histopathological images, which integrates both convolutional neural network (CNN) and GCN (named CNN-GCN) into a unified framework, where CNN learns high-level features from histopathological images for further adaptive graph construction, and the generated graph is then fed to GCN to learn the spatial features of histopathological images for the classification task. In particular, a novel clique GCN (cGCN) is proposed to learn more effective graph representation, which can arrange both forward and backward connections between any two graph convolution layers. Moreover, a new group graph convolution is further developed to replace the classical graph convolution of each layer in cGCN, so as to reduce redundant information and implicitly select superior fused feature representation. The proposed clique group GCN (cgGCN) is then embedded in the CNN-GCN framework (named CNN-cgGCN) to promote the learned spatial representation for diagnosis of breast cancers. The experimental results on two public breast histopathological image datasets indicate the effectiveness of the proposed CNN-cgGCN with superior performance to all the compared algorithms.

RNA kinase CLP1/Cbc regulates meiosis initiation in spermatogenesis.

CLP1, TSEN complex, and VCP are evolutionarily conserved proteins whose mutations are associated with neurodegenerative diseases. In this study, we have found that they are also involved in germline differentiation. To optimize both quantity and quality in gametes production, germ cells expand themselves through limited mitotic cycles prior to meiosis. Stemming from our previous findings on the correlation between mRNA 3'-processing and meiosis entry, here we identify that the RNA kinase Cbc, the Drosophila member of the highly conserved CLP1 family, is a component of the program regulating the transition from mitosis to meiosis. Using genetic manipulations in Drosophila testis, we demonstrate that nuclear Cbc is required to promote meiosis entry. Combining biochemical and genetic methods, we reveal that Cbc physically and/or genetically intersects with Tsen54 and TER94 (VCP ortholog) in this process. The C-terminal half of Tsen54 is both necessary and sufficient for its binding with Cbc. Further, we illustrate the functional conservation between Cbc and mammalian CLP1 in the assays of subcellular localization and Drosophila fertility. As CLP1, TSEN complex, and VCP have also been identified in neurodegenerations of animal models, a mechanism involving these factors seems to be shared in gametogenesis and neurogenesis.

Notch signaling governs the expression of glypican Dally to define the stem cell niche.

Extracellular glypicans play pivotal roles in organogenesis, stem cell maintenance and cancer development. However, the growth phenotypes associated with different levels of glypican are not consistent in development or tumorigenesis. This requires clarification on how the spatial patterns of glypican relate to the distribution of signaling molecules in different cellular contexts, and how glypican expression is regulated. We have previously reported that Dally, one of the glypican members in Drosophila, is required in the niche for the maintenance of germline stem cells (GSCs) via short-range BMP signaling in ovary. However, the regulatory mechanism of glypican pattern in the ovarian stem cell niche remains elusive. Our current data demonstrate that the Notch pathway is genetically upstream of Dally and its function to maintain GSCs relies on Dally expression. Combining yeast and fruit fly genetics, we illustrate that Dally is under the transcriptional control of Notch signaling via the transcription factor Su(H). Further, we assayed human glypicans and disease-associated variants in Drosophila ovary, which can serve as an effective system to evaluate the structure-function relationship of human homologs.

C. elegans-based screen identifies lysosome-damaging alkaloids that induce STAT3-dependent lysosomal cell death.

Lysosomes are degradation and signaling centers within the cell, and their dysfunction impairs a wide variety of cellular processes. To understand the cellular effect of lysosome damage, we screened natural small-molecule compounds that induce lysosomal abnormality using Caenorhabditis elegans (C. elegans) as a model system. A group of vobasinyl-ibogan type bisindole alkaloids (ervachinines A-D) were identified that caused lysosome enlargement in C. elegans macrophage-like cells. Intriguingly, these compounds triggered cell death in the germ line independently of the canonical apoptosis pathway. In mammalian cells, ervachinines A-D induced lysosomal enlargement and damage, leading to leakage of cathepsin proteases, inhibition of autophagosome degradation and necrotic cell death. Further analysis revealed that this ervachinine-induced lysosome damage and lysosomal cell death depended on STAT3 signaling, but not RIP1 or RIP3 signaling. These findings suggest that lysosome-damaging compounds are promising reagents for dissecting signaling mechanisms underlying lysosome homeostasis and lysosome-related human disorders.

WDR91 is a Rab7 effector required for neuronal development.

Early-to-late endosome conversion, which is essential for delivery of endosomal cargoes to lysosomes, requires switching of early endosome-specific Rab5 and PtdIns3P to late endosome-specific Rab7 and PtdIns(3,5)P2 In this study, we identify the WD40-repeat protein WDR91 as a Rab7 effector that couples Rab switching with PtdIns3P down-regulation on endosomes. Loss of WDR91 greatly increases endosomal PtdIns3P levels, arresting endosomes at an intermediate stage and blocking endosomal-lysosomal trafficking. WDR91 is recruited to endosomes by interacting with active guanosine triphosophate-Rab7 and inhibits Rab7-associated phosphatidylinositol 3-kinase activity. In mice, global Wdr91 knockout causes neonatal death, whereas brain-specific Wdr91 inactivation impairs brain development and causes postnatal death. Mouse neurons lacking Wdr91 accumulate giant intermediate endosomes and exhibit reduced neurite length and complexity. These phenotypes are rescued by WDR91 but not WDR91 mutants that cannot interact with Rab7. Thus, WDR91 serves as a Rab7 effector that is essential for neuronal development by facilitating endosome conversion in the endosome-lysosome pathway.

The BEACH-containing protein WDR81 coordinates p62 and LC3C to promote aggrephagy.

Autophagy-dependent clearance of ubiquitinated and aggregated proteins is critical to protein quality control, but the underlying mechanisms are not well understood. Here, we report the essential role of the BEACH (beige and Chediak-Higashi) and WD40 repeat-containing protein WDR81 in eliminating ubiquitinated proteins through autophagy. WDR81 associates with ubiquitin (Ub)-positive protein foci, and its loss causes accumulation of Ub proteins and the autophagy cargo receptor p62. WDR81 interacts with p62, facilitating recognition of Ub proteins by p62. Furthermore, WDR81 interacts with LC3C through canonical LC3-interacting regions in the BEACH domain, promoting LC3C recruitment to ubiquitinated proteins. Inactivation of LC3C or defective autophagy results in accumulation of Ub protein aggregates enriched for WDR81. In mice, WDR81 inactivation causes accumulation of p62 bodies in cortical and striatal neurons in the brain. These data suggest that WDR81 coordinates p62 and LC3C to facilitate autophagic removal of Ub proteins, and provide important insights into CAMRQ2 syndrome, a WDR81-related developmental disorder.

Negative regulation of phosphatidylinositol 3-phosphate levels in early-to-late endosome conversion.

Phosphatidylinositol 3-phosphate (PtdIns3P) plays a central role in endosome fusion, recycling, sorting, and early-to-late endosome conversion, but the mechanisms that determine how the correct endosomal PtdIns3P level is achieved remain largely elusive. Here we identify two new factors, SORF-1 and SORF-2, as essential PtdIns3P regulators in Caenorhabditis elegans. Loss of sorf-1 or sorf-2 leads to greatly elevated endosomal PtdIns3P, which drives excessive fusion of early endosomes. sorf-1 and sorf-2 function coordinately with Rab switching genes to inhibit synthesis of PtdIns3P, allowing its turnover for endosome conversion. SORF-1 and SORF-2 act in a complex with BEC-1/Beclin1, and their loss causes elevated activity of the phosphatidylinositol 3-kinase (PI3K) complex. In mammalian cells, inactivation of WDR91 and WDR81, the homologs of SORF-1 and SORF-2, induces Beclin1-dependent enlargement of PtdIns3P-enriched endosomes and defective degradation of epidermal growth factor receptor. WDR91 and WDR81 interact with Beclin1 and inhibit PI3K complex activity. These findings reveal a conserved mechanism that controls appropriate PtdIns3P levels in early-to-late endosome conversion.

[Comparison the effects between anatomical locked plate in combination with coracoclavicular ligament reconstruction and clavicular hook plate for the treatment of Neer II b distal clavicle fractures].

OBJECTIVE: To compare the therapeutic effects between anatomical locked plate combined with coracoclavicular ligament reconstruction and clavicular hook plate for treatment of distal clavicle fracture of Neer type II b. METHODS: From August 2010 to August 2013, 42 patients with Neer II b distal clavicle fractures were randomly divided into two groups as group A and group B. In group A, there were 22 cases including 14 males and 8 females with an average age of (44.2±11.6) years old. In group B, there were 20 cases including 11 males and 9 females with an average of (45.6±12.4) years old. The patients of group A were treated with anatomical locked plate combined with coracoclavicular ligament reconstruction,the patients of group B were treated with hook plate. All fractures were fresh, the time between injuries and operation was 24 hours to 7 days (mean,72 h). General information between the two groups was comparable before operation(P>0.05). Postoperative radiographic were followed up to observe the fracture healing,internal fixation and to measure coracoclavicular distance of two groups. Shoulder function after operation was evaluated by Constant-Murley score system. RESULTS: All patients were followed up with an average of 16.8 months (ranging 12 to 24 months). There was no nonunion,infection and other complications between two groups. The clavicular stress fracture occurred in 1 clavicular hook patient at 6 months after the operation. According to the Constant-Murley score system, that the scores of group A were 90.6±6.2, 91.8±4.8, 94.7±3.6 and 97.8±1.2 at 1st, 3rd, 6 month and last follow-up after operation were higher than those of group B 74.8±3.4, 78.4±4.4, 82.2±2.8 and 94.6±3.6 (P 0.05). The fracture healing time of group A (21.6±2.2) weeks was shorter than that of group B (25.8±2.5) weeks (P 0.05). There were no statistically significant differences between two groups in coracoclavicular distance at last follow-up (P>0.05). CONCLUSION: The anatomical locked plate combined with coracoclavicular ligament reconstruction need not expose shoulder and can reduce the incidence of postoperative pain and limited activity of shoulder, with fewer complication, it is advantageous to the shoulder joint function early recovery.

[The recent development of fiber-optic chemical sensor].

The present article provides a brief review of recent research on fiber-optic chemical sensor technology and the future development trends. Especially, fiber-optic pH chemical sensor, fiber-optic ion chemicl sensor, and fiber-optic gas chemical sensor are introduced respectively. Sensing film preparation methods such as chemical bonding method and sol-gel method were briefly reviewed. The emergence of new type fiber-microstructured optical fiber opened up a new development direction for fiber-optic chemical sensor. Because of its large inner surface area, flexible design of structure, having internal sensing places in fibers, it has rapidly become an important development direction and research focus of the fiber-optic chemical sensors. The fiber-optic chemical sensor derived from microstructured optical fiber is also discussed in detail. Finally, we look to the future of the fiber-optic chemical sensor.

[Comparison of the relativity of MRI appearance of cartilage injuries and postoperative effect of arthroscope on articular cartilage disease of knee].

OBJECTIVE: To analyze the indication of arthroscope by examining the correlations between cartilage injury degree confirmed by MRI and postoperative effect. METHODS: From Aug. 2005 to April 2008, 87 cases with knee osteoarthritis were treated by arthroscopes including 44 males and 43 females,aged from 16 to 67 years (means 46.3 years). Arthrodial cartilage of knee was graded by ICRS MR, and the therapeutic effect was evaluated by Lysholm scoring. RESULTS: All 87 knees of 87 cases were followed-up for from 12 to 30 months (averaged 23 months). The cartilage injury degree of knees was graded as follows: grade 4 in 30 cases, grade 3 in 23 cases, grade 2 in 20 cases, grade 1 in 12 cases, grade 0 in 2 cases, means grade (2.770 +/- 1.138). Postoperative Lysholm score was from 59 to 100, means (95.170 +/- 7.556). Coefficient correlation (r) = -0.152, P = 0.159 > 0.05. Although the results had no correlations between cartilage injury degree and Lysholm score, negative correlation tendency existed. CONCLUSION: The patients with higher grade of knee cartilage injury degree confirmed by MRI (1.5T) have worse effect after operation, the grade is not a gold standard as a operation indication in arthroscopic procedure.

Retromer is required for apoptotic cell clearance by phagocytic receptor recycling.

The cell surface receptor CED-1 mediates apoptotic cell recognition by phagocytic cells, enabling cell corpse clearance in Caenorhabditis elegans. Here, we found that the C. elegans intracellular protein sorting complex, retromer, was required for cell corpse clearance by mediating the recycling of CED-1. Retromer was recruited to the surfaces of phagosomes containing cell corpses, and its loss of function caused defective cell corpse removal. The retromer probably acted through direct interaction with CED-1 in the cell corpse recognition pathway. In the absence of retromer function, CED-1 associated with lysosomes and failed to recycle from phagosomes and cytosol to the plasma membrane. Thus, retromer is an essential mediator of apoptotic cell clearance by regulating phagocytic receptor(s) during cell corpse engulfment.

[Study on the correlation between knee osteoarthritis imaging and effects of arthroscope].

OBJECTIVE: To explore the indications of arthroscope for the treatment of knee osteoarthritis and investigate the correlation between knee osteoarthritis imaging and effects of arthroscope. METHODS: From 2005.8 to 2008.4, 86 patients with knee osteoarthritis underwent arthroscope examination and treatment. Among the patients, 44 patients were male, and 42 patients were female, ranging in age from 46 to 67 years, averaged 56.3 years. Arthrodial cartilage of knee was graded by ICRS MR, and by Kellgern Laqrence X-ray. All the patients were followed up, and the duration ranged from 12 to 30 months. The Lysholm score was evaluated at the follow-up time. RESULTS: Among 86 knees in 86 cases, cartilage injury degree of knees was graded as follows: grade 4 in 30 cases, grade 3 in 22 cases, grade 2 in 20 cases, grade 1 in 12 cases, grade 0 in 2 cases, mean grade (2.77 +/- 1.138). Postoperative Lysholm score ranged from 59 to 100, averaged (95.17 +/- 7.556), Kendall's correlation coefficient was -0.089, P = 0.317. There was no correlations between cartilage injury degree and Lysholm score. X-ray of knees was graded as follows: grade 4 in 0 cases, grade 3 in 24 cases, grade 2 in 38 cases, grade 1 in 17 cases, grade 0 in 7 cases, mean grade was (2.13 +/- 0.67), the Kendall's correlation coefficient was -0.851 with negative correlations (P = 0.036) between postoperative Lysholm score and K/L grade. CONCLUSION: There is no correlation between the grade of knee cartilage injury confirmed by MRI (1.5T) and effects of arthroscopy, and the grade is not a gold standard as an operation indication in arthroscope procedure. The K/L grade in X-ray had important effects.

Caenorhabditis elegans protein arginine methyltransferase PRMT-5 negatively regulates DNA damage-induced apoptosis.

Arginine methylation of histone and non-histone proteins is involved in transcription regulation and many other cellular processes. Nevertheless, whether such protein modification plays a regulatory role during apoptosis remains largely unknown. Here we report that the Caenorhabditis elegans homolog of mammalian type II arginine methyltransferase PRMT5 negatively regulates DNA damage-induced apoptosis. We show that inactivation of C. elegans prmt-5 leads to excessive apoptosis in germline following ionizing irradiation, which is due to a CEP-1/p53-dependent up-regulation of the cell death initiator EGL-1. Moreover, we provide evidence that CBP-1, the worm ortholog of human p300/CBP, functions as a cofactor of CEP-1. PRMT-5 forms a complex with both CEP-1 and CBP-1 and can methylate the latter. Importantly, down-regulation of cbp-1 significantly suppresses DNA damage-induced egl-1 expression and apoptosis in prmt-5 mutant worms. These findings suggest that PRMT-5 likely represses CEP-1 transcriptional activity through CBP-1, which represents a novel regulatory mechanism of p53-dependent apoptosis.

Adenine nucleotide translocator cooperates with core cell death machinery to promote apoptosis in Caenorhabditis elegans.

In Caenorhabditis elegans, the central cell-killing process is essentially controlled by the interplay of four apoptotic factors: EGL-1/BH3-only protein, CED-9/Bcl2, CED-4/Apaf1, and CED-3/caspase. In cells destined to die, EGL-1 binds to CED-9 and results in the release of CED-4 from the mitochondrion-tethered CED-9-CED-4 complex to the perinucleus, which facilitates processing of the CED-3 caspase to cause apoptosis. However, whether additional factors exist to regulate the cell-killing process remains largely unknown. We have identified here WAN-1, the C. elegans ortholog of mammalian adenine nucleotide translocator, as an important cell death regulator. Genetic inactivation of wan-1 significantly suppressed both somatic and germ line cell deaths in C. elegans. Consistently, chemical inhibition of WAN-1 activity also caused strong reduction of germ line apoptosis. WAN-1 localizes to mitochondria and can form complex with both CED-4 and CED-9. Importantly, the cell death initiator EGL-1 can disrupt the interaction between CED-9 and WAN-1. In addition, overexpression of WAN-1 induced ectopic cell killing dependently on the core cell death pathway. These findings suggest that WAN-1 is involved in the central cell-killing process and cooperates with the core cell death machinery to promote programmed cell death in C. elegans.

[Suture menisci with epidural transfixion pin to treating acute meniscus tear under arthroscope].

OBJECTIVE: To study the utility and effect of suturing menisci with epidural transfixion pin to treating acute meniscus tear under arthroscope. METHODS: Twenty-two cases with acute meniscus tear were selected, in which 18 were male and 4 were female,aged from 17 to 42 years with average of 28.5. The tearing menisci were sutured with epidural transfixion pin and unabsorbed suture. The follow-up were 6-12 months after operation. Meanwhile, Lysholm score, subjective symptoms and examination were recorded. RESULTS: Preoperative Lysholm scores were 46.72 +/- 13.46, whereas, postoperative ones were 89.43 +/- 18.21. There was significant difference between before and after operation (t = 1.85, P < 0.01). No recurrent interlocking, no pain in joint medialis and post-medialis space. McMurray test was negative. The complications about injury of blood vessel, nerves and tendons were not found during 6-12 months follow-up. CONCLUSION: The technique is advantageous in convenience, reliability, large suture strength and definite curative effect.

Mouse brains deficient in neuronal PDGF receptor-beta develop normally but are vulnerable to injury.

Platelet-derived growth factors (PDGFs) and PDGF receptors (PDGFRs) are widely expressed in the mammalian CNS, though their functional significance remains unclear. The corresponding null-knockout mutations are lethal. Here, we developed novel mutant mice in which the gene encoding the beta subunit of PDGFR (PDGFR-beta) was genetically deleted in CNS neurons to elucidate the role of PDGFR-beta, particularly in the post-natal stage. Our mutant mice reached adulthood without apparent anatomical defects. In the mutant brain, immunohistochemical analyses showed that PDGFR-beta detected in neurons and in the cells in the subventricular zone of the lateral ventricle in wild-type mice was depleted, but PDGFR-beta detected in blood vessels remained unaffected. The cerebral damage after cryogenic injury was severely exacerbated in the mutants compared with controls. Furthermore, TdT-mediated dUTP-biotin nick end labeling (TUNEL)-positive neuronal cell death and lesion formation in the cerebral hemisphere were extensively exacerbated in our mutant mice after direct injection of NMDA without altered NMDA receptor expression. Our results clearly demonstrate that PDGFR-beta expressed in neurons protects them from cryogenic injury and NMDA-induced excitotoxicity.