WD Repeat Research Articles

Nuclear farnesoid X receptor protects against bone loss by driving osteoblast differentiation through stabilizing RUNX2

The delicate balance between bone formation by osteoblasts and bone resorption by osteoclasts maintains bone homeostasis. Nuclear receptors (NRs) are now understood to be crucial in bone physiology and pathology. However, the function of the Farnesoid X receptor (FXR), a member of the NR family, in regulating bone homeostasis remains incompletely understood. In this study, in vitro and in vivo models revealed delayed bone development and an osteoporosis phenotype in mice lacking FXR in bone marrow mesenchymal stem cells (BMSCs) and osteoblasts due to impaired osteoblast differentiation. Mechanistically, FXR could stabilize RUNX2 by inhibiting Thoc6-mediated ubiquitination, thereby promoting osteogenic activity in BMSCs. Moreover, activated FXR could directly bind to the Thoc6 promoter, suppressing its expression. The interaction between RUNX2 and Thoc6 was mediated by the Runt domain of RUNX2 and the WD repeat of Thoc6. Additionally, Obeticholic acid (OCA), an orally available FXR agonist, could ameliorate bone loss in an ovariectomy (OVX)-induced osteoporotic mouse model. Taken together, our findings suggest that FXR plays pivotal roles in osteoblast differentiation by regulating RUNX2 stability and that targeting FXR may be a promising therapeutic approach for osteoporosis.

Dense stroma activates the TGF-β1/FBW7 axis to induce metabolic subtype switching in pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal diseases. Although several chemotherapy regimens have been developed over the past decades, few targeted therapies have shown a significant improvement in overall survival, partly due to the identification of PDAC as a single disease. Combining metabolomic analysis and immunohistochemistry staining with Oil Red O staining, analysis for the oxygen consumption rate and extracellular acidification rate, we stratified pancreatic cancer cells into two subtypes. The impact of transforming growth factor β (TGF-β)-1/F-box and WD repeat domain-containing 7 (FBW7) on the switch of the metabolic subtype was further validated in vitro and in vivo. Finally, cell growth was performed to identify the TGF-β1/FBW7 ratio as a molecular marker for gemcitabine resistance. PDAC was stratified into the glycolytic subtype and lipogenic subtype. Furthermore, pancreatic cancer-associated fibroblasts-derived TGF-β1 and tumor cell-derived FBW7 were demonstrated to co-determine the metabolic phenotypes in PDAC. A high TGF-β1/FBW7 ratio always represented the glycolytic PDAC with dense stroma. This subtype of PDAC exhibited mesenchymal features and was predictive of unfavorable prognoses, despite being more sensitive than the lipogenic subtype to combination treatment with gemcitabine and an inhibitor of TGF-β receptor I (TGF-βR1). The TGF-β1/FBW7 ratio could be regarded as a molecular marker of metabolic phenotypes in PDAC and may contribute to the development of effective therapeutic strategies to improve the survival of PDAC patients.

The Role of WDR77 in Cancer: More Than a PRMT5 Interactor.

WD repeat domain 77 protein (WDR77), a WD-40 domain-containing protein, is a crucial regulator of cellular pathways in cancer progression. While much of the past research on WDR77 has focused on its interaction with PRMT5 in histone methylation, WDR77's regulatory functions extend beyond this pathway, influencing diverse mechanisms such as mRNA translation, chromatin assembly, cell cycle regulation, and apoptosis. WDR77 is a key regulator of cell cycle progression, regulating the transition from the G1 phase. WDR77 regulates many signaling pathways such as TGFβ where its role in these cellular pathways underscores its broad oncogenic potential. WDR77 also assists and promotes certain transcription factors such as E2F. Furthermore, in certain cancers, WDR77 enhances steroid hormone receptor activity, uniquely linking it to hormone-driven malignancies. WDR77 often translocates between the nucleus and the cytoplasm, with its location dictating its role in the cell. WDR77 has the ability to adapt its function depending on its location which emphasizes its dynamic role in both promoting and inhibiting tumor growth, depending on cellular context. This dual function makes WDR77 an attractive therapeutic target, as disrupting its interactions with critical signaling pathways or modulating its translocation could yield novel strategies for cancer treatment. Given WDR77's role in oncogenic pathways independent of PRMT5, further exploration of WDR77 and its non-PRMT5-related activities may reveal additional therapeutic opportunities in an array of cancers.

Molecular Insights into the Role of the MET30 Protein and Its WD40 Domain in Colletotrichum gloeosporioides Growth and Virulence

Molecular Insights into the Role of the MET30 Protein and Its WD40 Domain in Colletotrichum gloeosporioides Growth and Virulence

Apaf-1 is an evolutionarily conserved DNA sensor that switches the cell fate between apoptosis and inflammation

Apoptotic protease activating factor 1 (Apaf-1) was traditionally defined as a scaffold protein in mammalian cells for assembling a caspase activation platform known as the ‘apoptosome’ after its binding to cytochrome c. Although Apaf-1 structurally resembles animal NOD-like receptor (NLR) and plant resistance (R) proteins, whether it is directly involved in innate immunity is still largely unknown. Here, we found that Apaf-1-like molecules from lancelets, fruit flies, mice, and humans have conserved DNA sensing functionality. Mechanistically, mammalian Apaf-1 recruits receptor-interacting protein 2 (RIP2, also known as RIPK2) via its WD40 repeat domain and promotes RIP2 oligomerization to initiate NF-κB-driven inflammation upon cytoplasmic DNA recognition. Furthermore, DNA binding of Apaf-1 determines cell fate by switching the cellular processes between intrinsic stimuli-activated apoptosis and inflammation. These findings suggest that Apaf-1 is an evolutionarily conserved DNA sensor and may serve as a cell fate checkpoint, which determines whether cells initiate inflammation or undergo apoptosis by distinct ligand binding.

Genome-Wide Identification and Expression Analysis of bHLH-MYC Family Genes from Mustard That May Be Important in Trichome Formation.

The trichomes of mustard leaves have significance due to their ability to combat unfavorable external conditions and enhance disease resistance. It was demonstrated that the MYB-bHLH-WD40 (MBW) ternary complex consists of MYB, basic Helix-Loop-Helix (bHLH), and WD40-repeat (WD40) family proteins and plays a key role in regulating trichome formation and density. The bHLH gene family, particularly the Myelocytomatosis (MYC) proteins that possess the structural bHLH domain (termed bHLH-MYC), are crucial to the formation and development of leaf trichomes in plants. bHLH constitutes one of the largest families of transcription factors in eukaryotes, of which MYC is a subfamily member. However, studies on bHLH-MYC transcription factors in mustard have yet to be reported. In this study, a total of 45 bHLH-MYC transcription factors were identified within the Brassica juncea genome, and a comprehensive series of bioinformatic analyses were conducted on their structures and properties: an examination of protein physicochemical properties, an exploration of conserved structural domains, an assessment of chromosomal positional distributions, an analysis of the conserved motifs, an evaluation of the gene structures, microsynteny analyses, three-dimensional structure prediction, and an analysis of sequence signatures. Finally, transcriptome analyses and a subcellular localization examination were performed. The results revealed that these transcription factors were unevenly distributed across 18 chromosomes, showing relatively consistent conserved motifs and gene structures and high homology. The final results of the transcriptome analysis and gene annotation showed a high degree of variability in the expression of bHLH-MYC transcription factors. Five genes that may be associated with trichome development (BjuVA09G22490, BjuVA09G13750, BjuVB04G14560, BjuVA05G24810, and BjuVA06G44820) were identified. The subcellular localization results indicated that the transcription and translation products of these five genes were expressed in the same organelle: the nucleus. This finding provides a basis for elucidating the roles of bHLH-MYC family members in plant growth and development, and the molecular mechanisms underlying trichome development in mustard leaves.

Inhibition of KLF5 promotes ferroptosis via the ZEB1/HMOX1 axis to enhance sensitivity to oxaliplatin in cancer cells

As a novel form of nonapoptotic cell death, ferroptosis is developing into a promising therapeutic target of dedifferentiating and therapy-refractory cancers. However, its application in pancreatic cancer is still unknown. In the preliminary research, we found that F-box and WD repeat domain-containing 7 (FBW7) inhibited the migration and proliferation of pancreatic cancer cells through its substrate c-Myc. We further found that another key substrate of FBW7, KLF5, could inhibit ferroptosis. Inhibiting KLF5 significantly enhances the cytotoxicity of oxaliplatin rather than other chemotherapy drugs. Mechanistically, we found that KLF5 inhibited the expression of heme oxygenase 1 (HMOX1) via repressing zinc finger E-box-binding homeobox 1 (ZEB1). Inhibition of KLF5 facilitated the cytotoxic effect of oxaliplatin via promoting ferroptosis. Oxaliplatin combined with KLF5 inhibitor significantly potentiated cell death in vitro and inhibited tumor growth in vivo compared with either treatment alone. These results reveal a critical role of KLF5 in sensitized chemotherapy of pancreatic cancer, and suggest that ferroptosis combined with platinum-based chemotherapy rather than gemcitabine-based chemotherapy is expected to bring better therapeutic effects.

Reconstructing NOD-like receptor alleles with high internal conservation in Podospora anserina using long-read sequencing.

NOD-like receptors (NLRs) are intracellular immune receptors that detect pathogen-associated cues and trigger defense mechanisms, including regulated cell death. In filamentous fungi, some NLRs mediate heterokaryon incompatibility, a self/non-self recognition process that prevents the vegetative fusion of genetically distinct individuals, reducing the risk of parasitism. The het-d and het-e NLRs in Podospora anserina are highly polymorphic incompatibility genes (het genes) whose products recognize different alleles of the het-c gene via a sensor domain composed of WD40 repeats. These repeats display unusually high sequence identity maintained by concerted evolution. However, some sites within individual repeats are hypervariable and under diversifying selection. Despite extensive genetic studies, inconsistencies in the reported WD40 domain sequence have hindered functional and evolutionary analyses. Here we demonstrate that the WD40 domain can be accurately reconstructed from long-read sequencing (Oxford Nanopore and PacBio) data, but not from Illumina-based assemblies. Functional alleles are usually formed by 11 highly conserved repeats, with different repeat combinations underlying the same phenotypic het-d and het-e incompatibility reactions. Protein structure models suggest that their WD40 domain folds into two 7-blade β-propellers composed of the highly conserved repeats, as well as three cryptic divergent repeats at the C-terminus. We additionally show that one particular het-e allele does not have an incompatibility reaction with common het-c alleles, despite being 11-repeats long. Our findings provide a robust foundation for future research into the molecular mechanisms and evolutionary dynamics of het NLRs, while also highlighting both the fragility and the flexibility of β-propellers as immune sensor domains.

High GRWD1 expression may predict clinically aggressive lower grade glioma, skin cutaneous melanoma, and kidney renal clear cell carcinoma carrying wild-type p53: a systematic study based on TCGA data analysis.

Glutamate-rich WD40 repeat containing 1 (GRWD1) is a novel oncogene/oncoprotein that downregulates the p53 tumor suppressor protein through several mechanisms. One important mechanism involves binding of GRWD1 to RPL11, which competitively inhibits the RPL11-MDM2 interaction and releases RPL11-mediated suppression of MDM2 ubiquitin ligase activity toward p53. Here, we mined the TCGA (The Cancer Genome Atlas) database to gain in-depth insight into the clinical relevance of GRWD1. We found that high expression of GRWD1 is associated with a poor prognosis for lower grade glioma (LGG) of the brain, skin cutaneous melanoma (SKCM), and kidney renal clear cell carcinoma (KIRC) carrying wild-type p53. Further investigations revealed that copy number alterations in the GRWD1 gene are one determinant of GRWD1 expression level. By contrast, even in patients with a diploid GRWD1 gene, high GRWD1 expression was associated with a poor prognosis for LGG, SKCM, and KIRC carrying wild-type p53. Additional studies suggest that some transcriptional factors may be involved in regulation of GRWD1 in cancers with a diploid GRWD1 gene. Taken together, the data presented herein suggest that high expression of GRWD1 may contribute to malignant behavior, and predict a clinically unfavorable prognosis for LGG, SKCM, and KIRC carrying wild-type p53.

WDR62 mediates MAPK/ERK pathway to stimulate DNA damage repair and attenuate cisplatin sensitivity in lung adenocarcinoma.

Chemotherapy resistance has long stood in the way of therapeutic advancement for lung cancer patients, the malignant tumor with the highest incidence and fatality rate in the world. Patients with lung adenocarcinoma (LUAD) now have a dismal prognosis due to the development of cisplatin (DDP) resistance, forcing them to use more costly second-line therapies. Therefore, overcoming resistance and enhancing patient outcomes can be achieved by comprehending the regulatory mechanisms of DDP resistance in LUAD. WD repeat domain 62 (WDR62) expression in LUAD tissues and in DDP-resistant or sensitive LUAD patients was analyzed bioinformatically, and a K-M plot was utilized to assess survival status. Real-time quantitative PCR was employed for WDR62 expression detection, cell-counting kit-8 assay for half maximal inhibitory concentration determination, flow cytometry for cell apoptosis detection, immunofluorescence for γ-H2AX expression analysis, and western blot for nonhomologous end joining repair and mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) pathway-related protein expression analysis. Poor prognosis was linked to WDR62, which was overexpressed in LUAD tissues and cells. Compared to sensitive cells, DDP-resistant cells had increased WDR62 expression. WDR62 knockdown may enhance DDP-induced cell apoptosis while reducing cell proliferation and DNA damage repair. Functional investigations verified that overexpressed WDR62's encouraging impact on DNA damage repair in A549/DDP cells could be reversed by MAPK inhibitors, increasing the cells' susceptibility to DDP. LUAD cells became less sensitive to DDP when WDR62 activated the MAPK/ERK pathway, which promoted DNA damage repair, indicating that DDP resistance might be reversed by treating LUAD with inhibitors of the MAPK pathway.

GEMIN5 and neurodevelopmental diseases: from functional insights to disease perception.

GEMIN5 is a predominantly cytoplasmic multifunctional protein, known to be involved in recognizing snRNAs through its WD40 repeats domain placed at the N-terminus. A dimerization domain in the middle region acts as a hub for protein-protein interaction, while a non-canonical RNA-binding site is placed towards the C-terminus. The singular organization of structural domains present in GEMIN5 enables this protein to perform multiple functions through its ability to interact with distinct partners, both RNAs and proteins. This protein exerts a different role in translation regulation depending on its physiological state, such that while GEMIN5 down-regulates global RNA translation, the C-terminal half of the protein promotes translation of its mRNA. Additionally, GEMIN5 is responsible for the preferential partitioning of mRNAs into polysomes. Besides selective translation, GEMIN5 forms part of distinct ribonucleoprotein complexes, reflecting the dynamic organization of macromolecular complexes in response to internal and external signals. In accordance with its contribution to fundamental cellular processes, recent reports described clinical loss of function mutants suggesting that GEMIN5 deficiency is detrimental to cell growth and survival. Remarkably, patients carrying GEMIN5 biallelic variants suffer from neurodevelopmental delay, hypotonia, and cerebellar ataxia. Molecular analyses of individual variants, which are defective in protein dimerization, display decreased levels of ribosome association, reinforcing the involvement of the protein in translation regulation. Importantly, the number of clinical variants and the phenotypic spectrum associated with GEMIN5 disorders is increasing as the knowledge of the protein functions and the pathways linked to its activity augments. Here we discuss relevant advances concerning the functional and structural features of GEMIN5 and its separate domains in RNA-binding, protein interactome, and translation regulation, and how these data can help to understand the involvement of protein malfunction in clinical variants found in patients developing neurodevelopmental disorders.

Identification of narciclasine as a novel NRF2 inhibitor

Cancer genome sequencing studies have identified somatic mutations in the KEAP1/NRF2 pathway. In an effort to identify novel NRF2 small molecule inhibitor(s), we have screened a natural compound library comprising 1,330 chemicals in A549-ARE-GFP-luciferase cells and identified that narciclasine significantly inhibits NRF2-dependent luciferase activity. Narciclasine suppressed the expression of NRF2 and NRF2 target genes, caused significant oxidative stress, and sensitized cisplatin-mediated apoptosis in A549 cells. In addition, we have observed that WD Repeat Domain 43 (WDR43) serves as a direct target of narciclasine for the inhibition of NRF2 as narciclasine binds to recombinant WDR43 in vitro and silencing WDR43 attenuated the inhibition of NRF2 by narciclasine in A549 cells. Finally, we observed that administration of narciclasine significantly decreased the growth of A549 xenografts. Together, our results demonstrate that the inhibition of NRF2 by narciclasine is mediated by WDR43 and future studies are necessary to elucidate the exact mechanism how WDR43 mediates the inhibition of NRF2 by narciclasine.

Upregulation of WDR4 mediated by RBFOX2 promotes laryngeal cancer progression through the WDR4/m7G/lncRNA ZFAS1/RBFOX2 axis.

High levels of the N7 methylguanosine (m7G) methyltransferase WD repeat domain 4 (WDR4) are associated with the progression of multiple tumors, including head and neck squamous cell carcinoma. Laryngeal cancer (LC) is the second most common malignant tumor of the head and neck. However, the role of WDR4 in LC remains unclear. Here, we found that WDR4 expression was significantly upregulated in LC tissues and cells. Silencing WDR4 inhibited proliferation, invasion, and epithelial-mesenchymal transition (EMT, manifested by an increase in E-cadherin protein levels and a decrease in N-cadherin and Vimentin protein levels) in TU177 and M4E cells. Furthermore, the levels of m7G and ZFAS1 were significantly upregulated in LC tissues and cells. Mechanistic studies revealed that WDR4 upregulated the levels of ZFAS1 and RBFOX2 proteins by promoting the stability of ZFAS1 in an m7G-dependent manner, and RBFOX2 promoted WDR4 expression by binding to WDR4 mRNA. Overexpression of WDR4 increased m7G and ZFAS1 levels, whereas overexpression of WDR4 with m7G catalytic site mutation had no effect on m7G and ZFAS1 levels in TU177 and M4E cells. Silencing ZFAS1 or RBFOX2 counteracted the promoting effect of WDR4 overexpression on the malignant proliferation of TU177 and M4E cells. TU177 cells transfected with sh-WDR4 lentiviral vectors were intraperitoneally injected into nude mice to construct xenograft tumor models. Knockdown of WDR4 significantly inhibited LC tumor growth in vivo. In conclusion, RBFOX2-mediated upregulation of WDR4 promoted LC progression through the WDR4/m7G/ZFAS1/RBFOX2 axis.

A Systematic Blueprint to Ligand the Proteome.

The Target 2035 initiative is an ambitious proposal to discover pharmacological tools across the human proteome. This Viewpoint summarizes an approach inspired by that goal leveraging DNA-encoded library coupled with machine learning approaches to assess the ligandability of the WD40 repeat target class of proteins.

Functionally active modulators targeting the LRRK2 WD40 repeat domain identified by FRASE-bot in CACHE Challenge #1.

Critical Assessment of Computational Hit-Finding Experiments (CACHE) Challenges emerged as real-life stress tests for computational hit-finding strategies. In CACHE Challenge #1, 23 participants contributed their original workflows to identify small-molecule ligands for the WD40 repeat (WDR) of LRRK2, a promising Parkinson's target. We applied the FRASE-based hit-finding robot (FRASE-bot), a platform for interaction-based screening allowing a drastic reduction of the explorable chemical space and a concurrent detection of putative ligand-binding sites. In two screening rounds, 84 compounds were procured for experimental testing and 8 were confirmed to bind LRRK2-WDR with dissociation constants (K d) ranging from 3 to 41 μM. To investigate the functional effect of WDR ligands, they were tested for their ability to modify the LRRK2 activity markers in HEK293T cells. Two compounds showed statistically significant increases in the kinase activity of WT LRRK2, and two compounds affected the conformation and kinase activity of major LRRK2 mutants.

PhSLB1 Regulates Branch Development in Petunia

F-box proteins play crucial roles in various developmental stages in plants, such as shoot branching. As an important ornamental and model plant, the branch development of petunia has always been a hot research topic. In our study, the homologous gene of SMALL LEAF AND BUSHY1 (SLB1) was isolated from Petunia ×hybrida cv. Mitchell Diploid. PhSLB1 contained a C-terminal WD40 repeat domain and an N-terminal F-box domain. An analysis of expression indicated that PhSLB exhibited the highest expression in roots, whereas expression levels were lowest in stems and leaves. Subcellular localization assays demonstrated that PhSLB1 was localized on the nucleus. Furthermore, RNA interference (RNAi) of PhSLB1 in petunia significantly increased the branch number. Quantitative real-time polymerase chain reaction showed that PhSLB1 not only regulated cytokinin and strigolactone pathway but also affected the expression of some key branching-related genes, such as PhBRC1, PhKNOX, PhH2A, and PhL27. Our research establishes a theoretical groundwork for revealing the mechanism by which SLB1 regulates branch development.

Design, synthesis, and evaluation of novel stilbene derivatives that degrade acidic nucleoplasmic DNA-binding protein 1 (And1) and synergize with PARP1 inhibitor in NSCLC cells

Specifically inducing the degradation of acidic nucleoplasmic DNA-binding protein 1 (And1) is a promising antitumor strategy. Our previous study identified Bazedoxifene (BZA) and CH3 as specific And1 degraders and validated their activity in reversing radiotherapy resistance in vitro and in vivo. However, unelucidated structure-activity relationships and moderate activity have limited their application. In this study, 27 novel CH3 derivatives were designed and synthesised based on the cavity topology of the WD40 domain of And1. Among them, A15 with a “V” conformation significantly induced And1 degradation in NSCLC cells. In addition, this study demonstrated a potential synthetic lethal effect of And1 degraders and PARP1 inhibitors. 1 µM of Olaparib in combination with 5 µM of A15 significantly inhibited the proliferation of A549 and H460 cells. Overall, these compounds are valuable tools for elucidating And1 biology, and their special spatial conformation make them promising candidates for future optimisation studies.

Roles of WDR12 and MRTO4 genes in colorectal cancer

Colorectal cancer refers to malignant tumors occurring in the walls of the colon or rectum. The roles of WD Repeat Domain 12 (WDR12) and mitochondrial ribosome-associated tumor suppressor 4 (MRTO4) genes in colorectal cancer remain unclear. The colorectal cancer dataset GSE113513 configuration file was downloaded from the gene expression omnibus database generated from GPL15207. Differentially expressed genes screening, functional enrichment analysis, gene set enrichment analysis, Weighted Gene Co-expression Network Analysis, construction and analysis of protein–protein interaction networks, survival analysis, and gene expression heatmap plotting were conducted. Comparative toxicogenomics database analysis was performed to find diseases most relevant to core genes. TargetScan was used to screen miRNAs regulating core genes. A total of 3106 differentially expressed genes were identified. According to gene ontology analysis, they mainly enriched in organic acid metabolic processes, condensed chromosome kinetochore, oxidoreductase activity, and cell cycle. In Kyoto encyclopedia of genes and genomes analysis, they primarily concentrated in the cell cycle, TGF-β signaling pathway, Jak-STAT signaling pathway, PI3K-Akt signaling pathway, Ras signaling pathway, TNF signaling pathway, p53 signaling pathway, NF-kB signaling pathway, and WNT signaling pathway. Weighted Gene Co-expression Network Analysis with a soft thresholding power set to 12 generated 29 modules. The protein–protein interaction network identified 6 core genes (DDX27, NAT10, WDR12, DKC1, MRTO4, and NOP56). Survival analysis showed core genes (POSTN, MYH11, LUM, COL6A3, and COL4A1) as risk factors. Gene expression heatmap revealed high expression of core genes (WDR12 and MRTO4) in colorectal samples. Comparative toxicogenomics database analysis linked core genes (WDR12 and MRTO4) with local tumor infiltration, bowel obstruction, abdominal pain, and colorectal neoplasms. WDR12 and MRTO4 genes are highly expressed in colorectal cancer, potentially influencing its progression.

WDR49-Positive Astrocytes Mark Severity of Neurodegeneration in Frontotemporal Lobar Degenerationand Alzheimer's Disease.

A subpopulation of astrocytes expressing WD Repeat Domain 49 (WDR49) was recently identified in frontotemporal lobar degeneration (FTLD) with GRN pathogenic variants. This is the first study to investigate their expression and relation to pathology in other FTLD subtypes and Alzheimer's disease (AD). In a postmortem cohort of TDP-43 proteinopathies (12 GRN, 11 C9orf72, 9 sporadic TDP-43), tauopathies (13 MAPT, 8 sporadic tau), 10 AD, and four controls, immunohistochemistry and immunofluorescence were performed for WDR49 and pathological inclusions on frontal, temporal, and occipital cortical sections. WDR49-positive cell counts (adjusted per mm2) were examined and related to digitally quantified percentage areas of TDP-43/tau pathology and semiquantitative scores of neurodegeneration. Quantitative colocalization analysis of WDR49 and pathological inclusions was done. WDR49-positive astrocytes were present across FTLD subtypes and AD in the brain parenchyma and (peri-)vascular space, with distinct morphological patterns, and were particularly enriched in gray matter. In controls, sporadic WDR49-positive cells were found enveloping vessels. WDR49-positive astrocytes were most abundant in the frontal cortex (FC)of GRN cases and temporal cortex in GRN, AD, and sporadic primary tauopathy. In the occipital cortex, only a few cells were found across groups. WDR49-positive astrocyte counts positively correlated with the severity of neurodegeneration and TDP-43 pathology but not tauopathy. Furthermore, in frontotemporal cortices, WDR49 partly colocalized with TDP-43 (14%-21%) and tau (31%-45%). In conclusion, WDR49 is a marker for a subset of astrocytes with different morphologies across FTLD and AD, reflecting the severity of neurodegeneration. These astrocytes may become activated in neurodegeneration in response to pathological damage and migrate from the vessel wall to the parenchyma.

FBXW7 in gastrointestinal cancers: from molecular mechanisms to therapeutic prospects

F-box and WD repeat domain-containing 7 (FBXW7), formerly known as hCdc4, hAGO Fbw7, or SEL10, plays a specific recognition function in SCF-type E3 ubiquitin ligases. FBXW7 is a well-established cancer suppressor gene that specifically controls proteasomal degradation and destruction of many key oncogenic substrates. The FBXW7 gene is frequently abnormal in human malignancies especially in gastrointestinal cancers. Accumulating evidence reveals that mutations and deletions of FBXW7 are participating in the occurrence, progression and treatment resistance of human gastrointestinal cancers. Considering the current therapeutic challenges faced by gastrointestinal cancers, elucidating the biological function and molecular mechanism of FBXW7 can provide new perspectives and references for future personalized treatment strategies. In this review, we elucidate the key molecular mechanisms by which FBXW7 and its substrates are involved in gastrointestinal cancers. Furthermore, we discuss the consequences of FBXW7 loss or dysfunction in tumor progression and underscore its potential as a prognostic and therapeutic biomarker. Lastly, we propose potential therapeutic strategies targeting FBXW7 to guide the precision treatment of gastrointestinal cancers.