Bone controls browning of white adipose tissue and protects from diet-induced obesity through Schnurri-3-regulated SLIT2 secretion.

The skeleton has been suggested to function as an endocrine organ controlling whole organism energy balance, however the mediators of this effect and their molecular links remain unclear. Here, utilizing Schnurri-3-/- (Shn3-/-) mice with augmented osteoblast activity, we show Shn3-/-mice display resistance against diet-induced obesity and enhanced white adipose tissue (WAT) browning. Conditional deletion of Shn3 in osteoblasts but not adipocytes recapitulates lean phenotype of Shn3-/-mice, indicating this phenotype is driven by skeleton. We further demonstrate osteoblasts lacking Shn3 can secrete cytokines to promote WAT browning. Among them, we identify a C-terminal fragment of SLIT2 (SLIT2-C), primarily secreted by osteoblasts, as a Shn3-regulated osteokine that mediates WAT browning. Lastly, AAV-mediated Shn3 silencing phenocopies the lean phenotype and augmented glucose metabolism. Altogether, our findings establish a novel bone-fat signaling axis via SHN3 regulated SLIT2-C production in osteoblasts, offering a potential therapeutic target to address both osteoporosis and metabolic syndrome.

MiR-1271-5p promotes the growth and migration of neuroblastoma cells by regulating ACY-1.

Background: Aminoacylase 1 (ACY-1) has been found to be a tumor suppressor gene in neuroblastoma (NB). This study aimed to identify and verify the microRNAs (miRNAs) that may regulate ACY-1 through database prediction analysis, and verify the mutual regulatory effect of miRNA and ACY-1 in NB through cell experiments. Methods: The miRNAs that might bind ACY-1 were predicted and selected by TargetScan, miRTarBase and four other databases, the expression of the predicted miRNAs and ACY-1 was detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) in four groups of clinical samples, and the differentially expressed miRNAs were screened. Then, luciferase vector was constructed according to the ACY-1 gene sequence to detect whether ACY-1 binds to the selected miRNA. Then, miR-1271-5p expression was silenced to detect miR-1271-5p function in the growth and migration of NB. Finally, ACY-1 and miR-1271-5p were silenced to change ACY-1 expression, and ACY-1 function in NB and the regulatory role of miR-1271-5p were explored. Results: ACY-1 was downregulated in NB, miR-1271-5p was upregulated in NB, and miR-1271-5p could be targeted to ACY-1. Silencing miR-1271-5p expression can reduce cell viability and inhibit tumor progression. After interfering with ACY-1 expression in cells, cell viability was enhanced, apoptosis was significantly decreased, and migration and invasion were enhanced. After partially restoring ACY-1 expression, the effect of si-ACY-1 on cells was weakened. In SK-N-SH and SH-SY-5Y cells, the miR-1271-5p inhibitor restored ACY-1 expression and improved ACY-1 function. Conclusions: MiR-1271-5p can promote the growth and migration of tumor cells by inhibiting ACY-1 expression in NB.

Fighting the invisible foe in cancer therapy.

In this issue of Cell Host & Microbe, Huang et al. determine that an oncogenic bacterium contributes to colorectal cancer progression and resistance to receptor tyrosine kinase inhibitors. These findings highlight the need for an integrative approach for cancer treatment that considers the influence of the microbiome.

DNA-DISK: Automated end-to-end data storage via enzymatic single-nucleotide DNA synthesis and sequencing on digital microfluidics.

In the age of information explosion, the exponential growth of digital data far exceeds the capacity of current mainstream storage media. DNA is emerging as a promising alternative due to its higher storage density, longer retention time, and lower power consumption. To date, commercially mature DNA synthesis and sequencing technologies allow for writing and reading of information on DNA with customization and convenience at the research level. However, under the disconnected and nonspecialized mode, DNA data storage encounters practical challenges, including susceptibility to errors, long storage latency, resource-intensive requirements, and elevated information security risks. Herein, we introduce a platform named DNA-DISK that seamlessly streamlined DNA synthesis, storage, and sequencing on digital microfluidics coupled with a tabletop device for automated end-to-end information storage. The single-nucleotide enzymatic DNA synthesis with biocapping strategy is utilized, offering an ecofriendly and cost-effective approach for data writing. A DNA encapsulation using thermo-responsive agarose is developed for on-chip solidification, not only eliminating data clutter but also preventing DNA degradation. Pyrosequencing is employed for in situ and accurate data reading. As a proof of concept, DNA-DISK successfully stored and retrieved a musical sheet file (228 bits) with lower write-to-read latency (4.4 min of latency per bit) as well as superior automation compared to other platforms, demonstrating its potential to evolve into a DNA Hard Disk Drive in the future.

Development and validation of novel interpretable survival prediction models based on drug exposures for severe heart failure during vulnerable period.

BACKGROUND: Severe heart failure (HF) has a higher mortality during vulnerable period while targeted predictive tools, especially based on drug exposures, to accurately assess its prognoses remain largely unexplored. Therefore, this study aimed to utilize drug information as the main predictor to develop and validate survival models for severe HF patients during this period. METHODS: We extracted severe HF patients from the MIMIC-IV database (as training and internal validation cohorts) as well as from the MIMIC-III database and local hospital (as external validation cohorts). Three algorithms, including Cox proportional hazards model (CoxPH), random survival forest (RSF), and deep learning survival prediction (DeepSurv), were applied to incorporate the parameters (partial hospitalization information and exposure durations of drugs) for constructing survival prediction models. The model performance was assessed mainly using area under the receiver operator characteristic curve (AUC), brier score (BS), and decision curve analysis (DCA). The model interpretability was determined by the permutation importance and Shapley additive explanations values. RESULTS: A total of 11,590 patients were included in this study. Among the 3 models, the CoxPH model ultimately included 10 variables, while RSF and DeepSurv models incorporated 24 variables, respectively. All of the 3 models achieved respectable performance metrics while the DeepSurv model exhibited the highest AUC values and relatively lower BS among these models. The DCA also verified that the DeepSurv model had the best clinical practicality. CONCLUSIONS: The survival prediction tools established in this study can be applied to severe HF patients during vulnerable period by mainly inputting drug treatment duration, thus contributing to optimal clinical decisions prospectively.

Short-term usage of proton pump inhibitors during admission was associated with increased risk of rehospitalization in critically ill patients with myocardial infarction: a cohort study.

PURPOSE: Previous studies showed that long-term use of proton pump inhibitors (PPIs) was associated with cardiovascular events. However, the impact of short-term PPI exposure on intensive care unit (ICU) patients with myocardial infarction (MI) remains largely unknown. This study aims to determine the precise correlation between short-term PPI usage during hospitalization and prognostic outcomes of ICU-admitted MI patients using Medical Information Mart for Intensive Care IV database (MIMIC-IV). METHODS: Propensity score matching (PSM) was applied to adjust confounding factors. The primary study outcome was rehospitalization with mortality and length of stay as secondary outcomes. Binary logistic, multivariable Cox, and linear regression analyses were employed to estimate the impact of short-term PPI exposure on ICU-admitted MI patients. RESULTS: A total of 7249 patients were included, involving 3628 PPI users and 3621 non-PPI users. After PSM, 2687 pairs of patients were matched. The results demonstrated a significant association between PPI exposure and increased risk of rehospitalization for MI in both univariate and multivariate [odds ratio (OR) = 1.157, 95% confidence interval (CI) 1.020-1.313] analyses through logistic regression after PSM. Furthermore, this risk was also observed in patients using PPIs > 7 days, despite decreased risk of all-cause mortality among these patients. It was also found that pantoprazole increased the risk of rehospitalization, whereas omeprazole did not. CONCLUSION: Short-term PPI usage during hospitalization was still associated with higher risk of rehospitalization for MI in ICU-admitted MI patients. Furthermore, omeprazole might be superior to pantoprazole regarding the risk of rehospitalization in ICU-admitted MI patients.

Gene therapy in Aß-induced cell and mouse models of Alzheimer's disease through compensating defective mitochondrial complex I function.

BACKGROUND: Alzheimer's disease (AD) is the most common neurogenerative disorder without effective treatments. Defects in mitochondrial complex I are thought to contribute to AD pathogenesis. The aim of this study is to explore whether a novel gene therapy transducing yeast complex I gene NDI1 can be used to treat AD with severely reduced complex I function in cell and animal models. METHODS: The differentiated human neural cells were induced by Aß1-42 to establish the AD cell model, and adeno-associated virus serotype 9 (AAV9) was used to transduce yeast NDI1 into the cell model. Aß1-42 was injected into the hippocampus area of the brain to establish the AD mouse model. AAV9-NDI1 was injected stereotaxically into the hippocampus area to test the therapeutic effect. RESULTS: The expressed yeast complex I had an ameliorating effect on the defective function of human complex I and cellular pathological characteristics in the AD cell model. Furthermore, AAV9-NDI1 gene therapy in the hippocampus had a therapeutic effect on various aspects of mitochondrial function, histopathological characteristics and neurological defects in the AD mouse model. In addition, AAV9-NDI1 injection into the hippocampus of normal mice did not cause any adverse effect. CONCLUSIONS: Compensating mitochondrial complex I function with yeast NDI1 is effective for gene therapy in Aß-induced AD cell and mouse models. The results of this study offer a novel strategy and approach for treating AD types characterized by complex I abnormalities.

Association between serum cotinine and muscle mass: results from NHANES 2011-2018.

PURPOSE: Recently, the detrimental effect of cigarette smoking on muscle metabolism has attracted much attention, but the relationship between cigarette smoking and muscle mass is poorly understood. Thus, this study investigated the association between exposure to cigarette smoke, defined based on serum cotinine, and muscle mass in the US population. METHODS: We utilized National Health and Nutrition Examination Survey (NHANES) data between 2011 and 2018 for analysis. Data on serum cotinine, muscle mass (quantified by appendicular skeletal muscle mass index, ASMI), and covariates were extracted and analyzed. Weighted multivariate linear regression analyses and smooth curve fittings were performed to investigate the association between serum cotinine and ASMI. Subgroup analyses were stratified by gender, race and smoking status. When nonlinearity was detected, the threshold effects were analyzed using a two-piecewise linear regression model. RESULTS: In total, 8004 participants were included for analysis. The serum level of cotinine was negatively associated with ASMI in the fully adjusted model. Furthermore, comparing participants in the highest vs. the lowest tertile of serum cotinine, we found that ASMI decreased by 0.135 Kg/m2. In subgroup analysis stratified by gender and race, the association between serum cotinine and ASMI remained significant in all genders and races. In addition, the association remained significant among current and former smokers, but not among those who never smoked. Smooth curve fittings showed nonlinear relationships between serum cotinine and ASMI, with the inflection points identified at 356 ng/mL. CONCLUSIONS: Our study revealed that serum cotinine was negatively related to muscle mass. This finding improves our understanding of the deleterious effects of cigarette smoking on muscle mass and highlights the importance of smoking cessation for muscle health.

Patient satisfaction with letter-based communication of LCS pulmonary nodule results.

OBJECTIVE: To analyze patient satisfaction with letter-based communication of lung cancer screening (LCS) pulmonary nodule results. STUDY DESIGN: Prospective randomized controlled trial of LCS between May and December 2019. METHODS: All participants came from a prospective randomized controlled study on pulmonary nodule results in LCS with low-dose CT (LDCT) to analyze patient satisfaction, perception of information received via letters, preferred methods of receiving results, and dissatisfaction-related characteristics. RESULTS: A total of 153 patients were detected to have pulmonary nodules among 600 recruited participants in the lung cancer high-risk group screened using LDCT. Most of the patients were satisfied with receiving pulmonary nodule results via letters (78.4%; n = 120) and agreed that the letters contained an appropriate amount of information (83.7%; n = 128). Univariate logistic regression analysis revealed that satisfaction was related to age (OR, 0.905; 95% CI, 0.832-0.985), education level (OR, 0.367; 95% CI, 0.041-3.250), no family history of cancer (OR, 0.100; 95% CI, 0.011-0.914), and the number of nodules (OR, 6.028; 95% CI, 1.641-22.141). Of the patients who reported dissatisfaction with letter-based communication (7.2%; n = 11), the most common reasons cited were that they contained insufficient patient education materials and that it was difficult to comprehend the medical terminology. The majority of participants (61.4%; n = 94) reported that they would prefer the letter-based communication. No correlation was identified between satisfaction and gender, smoking status, alcohol consumption, risk factors, nodule size, or nodule location. CONCLUSIONS: Patients were generally satisfied with receiving their LCS pulmonary nodule results via letters, reporting that the letters included adequate information about their diagnosis and follow-up steps. This may provide a basis for feasible result communication via letters for cancer screening programs in underdeveloped regions in China.

Deciphering the interplay of gut microbiota and metabolomics in retinal vein occlusion.

This study aims to explore the link between retinal vein occlusion (RVO), a blinding ocular condition, and alterations in gut microbiota composition, to offer insights into the pathogenesis of RVO. Fecal samples from 25 RVO patients and 11 non-RVO individuals were analyzed using 16S rRNA sequencing and liquid chromatography-mass spectrometry (LC-MS). Significant differences in the abundance of gut microbial species were noted between RVO and non-RVO groups. At the phylum level, the RVO group showed an elevation in the ratio of Firmicutes to Bacteroidetes. At the genus level, the RVO group showed higher abundance in Escherichia_Shigella (P < 0.05) and less abundance in Parabacteroides (P < 0.01) than the non-RVO group. Functional predictions indicated reduced folate synthesis, biotin metabolism, and oxidative phosphorylation, with an increase in butyric acid metabolism in the RVO group. LC-MS analysis showed significant differences in purine metabolism, ABC transporters, and naphthalene degradation pathways, especially purine metabolism. Pearson correlation analysis revealed significant associations between bacterial genera and fecal metabolites. Enrichment analysis highlighted connections between specific metabolites and bacterial genera. The findings showed that the dysregulation of gut microbiota was observed in RVO patients, suggesting the gut microbiota as a potential therapeutic target. Modulating the gut microbiota could be a novel strategy for managing RVO and improving patient outcomes. Furthermore, the study findings suggest the involvement of gut microbial dysbiosis in RVO development, underscoring the significance of understanding its pathogenesis for effective treatment development. IMPORTANCE: Retinal vein occlusion (RVO) is a blinding ocular condition, and understanding its pathogenesis is crucial for developing effective treatments. This study demonstrates significant differences in gut microbiota composition between RVO patients and non-RVO individuals, implicating the involvement of gut microbial dysbiosis in RVO development. Functional predictions and metabolic profiling provide insights into the underlying mechanisms, highlighting potential pathways for therapeutic intervention. These findings suggest that modulating the gut microbiota might be a promising strategy for managing RVO and improving patient outcomes.

Phase interface engineering enables state-of-the-art half-Heusler thermoelectrics.

In thermoelectric, phase interface engineering proves effective in reducing the lattice thermal conductivity via interface scattering and amplifying the density-of-states effective mass by energy filtering. However, the indiscriminate introduction of phase interfaces inevitably leads to diminished carrier mobility. Moreover, relying on a singular energy barrier is insufficient for comprehensive filtration of low-energy carriers throughout the entire temperature range. Addressing these challenges, we advocate the establishment of a composite phase interface using atomic layer deposition (ALD) technology. This design aims to effectively decouple the interrelated thermoelectric parameters in ZrNiSn. The engineered coherent dual-interface energy barriers substantially enhance the density-of-states effective mass across the entire temperature spectrum while preser carrier mobility. Simultaneously, the strong interface scattering on phonons is crucial for curtailing lattice thermal conductivity. Consequently, a 40-cycles TiO2 coating on ZrNi1.03Sn0.99Sb0.01 achieves an unprecedented zT value of 1.3 at 873 K. These findings deepen the understanding of coherent composite-phase interface engineering.

Multi-level data fusion strategy based on spectral and image information for identifying varieties of soybean seeds.

Rapid identification of soybean seed varieties is crucial for agricultural production and seed quality. Identifying varieties of soybean seed using conventional chemical methods is time-consuming, destructive, and inappropriate for seed quality evaluation. This study utilized hyperspectral imaging technology (HSI) to identify four varieties of soybean seeds. The hyperspectral images of soybean seeds were collected in the spectral range of 400-1000 nm. A multi-level data fusion strategy based on spectral and image information was proposed to improve the accuracy of model. Subsequently, the multi-level data fusion strategy based on partial least squares discriminant analysis (PLS-DA) was used to establish the classification models of soybean seeds. Compared with the models using individual analytical sources, the results demonstrated that the models with multi-level data fusion strategy obtained better prediction performance. The high-level data fusion (HLDF) based on Bayesian consensus provided the optimal results with an accuracy (Acc) and F1-score of 93.13 % and 93.70 % in the prediction phase, respectively. Therefore, the multi-level data fusion strategy can be used as an identification method for soybean seed varieties and an effective approach to enhance the discriminatory capability of models.

Minimally invasive techniques utilizing the "Joy Stick" method for managing irreducible flexion-type supracondylar fractures of the humerus in older children.

OBJECTIVE: In this study, we investigated the efficacy of percutaneous poking reduction and Kirschner wire fixation in older children with irreducible supracondylar flexion-type fractures of the humerus. METHODS: This retrospective investigation included 27 children, comprising 15 males and 12 females, aged between 10 years and 3 months to 14 years and 11 months, all diagnosed with a flexion-type supracondylar fracture of the humerus within one week of trauma. All patients underwent surgery under general anesthesia. Following unsuccessful manual reduction, percutaneous poking reduction with Kirschner wires was performed under C-arm fluoroscopy to achieve fracture reduction. Following successful reduction, three 2.0 mm Kirschner wires were inserted in a cross pattern to secure the fracture ends. Postoperatively, the elbow joint was immobilized in a functional position with a plaster cast for four weeks. RESULTS: Follow-up in the outpatient department ranged from 9 to 36 months. Clinical functional assessment using Flynn's criteria rated 24 cases as excellent, 2 as good, and 1 as fair, yielding an overall efficacy of 96.3%. No cases of fracture re-displacement, fracture fragment necrosis, or other complications such as nonunion, iatrogenic nerve injury, myositis ossificans, or long-term elbow joint dysfunction were observed during the postoperative follow-up. CONCLUSION: The percutaneous poking reduction and Kirschner wire fixation technique is a simple and reliable procedure for treating irreducible flexion-type supracondylar fractures of the humerus in older children, with minimal trauma. This technique offers substantial stability for the fracture and results in excellent long-term recovery of joint function.

Deficiency of SIAH1 promotes the formation of filopodia by increasing the accumulation of FASN in liver cancer.

It has been shown that the formation of filopodia is a key step in tumor cell metastasis, but there is limited research regarding its mechanism. In this study, we demonstrated that fatty acid synthase (FASN) promoted filopodia formation in liver cancer cells by regulating fascin actin-bundling protein 1 (FSCN1), a marker protein for filopodia. Mechanistically, on the one hand, the accumulation of FASN is caused by the enhanced deubiquitination of FASN mediated by UCHL5 (ubiquitin c-terminal hydrolase L5). In this pathway, low expression of SIAH1 (Seven in absentia homolog 1) can decrease the ubiquitination and degradation of ADRM1 (adhesion regulating molecule 1) thereby increasing its protein level, which will recruit and activate the deubiquitination enzyme UCHL5, leading to FASN undergo deubiquitination and escape from proteasomal degradation. On the other hand, the accumulation of FASN is related to its weakened ubiquitination, where SIAH1 directly acts as a ubiquitin ligase toward FASN, and low expression of SIAH1 reduces the ubiquitination and degradation of FASN. Both the two pathways are involved in the regulation of FASN in liver cancer. Our results reveal a novel mechanism for FASN accumulation due to the low expression of SIAH1 in human liver cancer and suggest an important role of FASN in filopodia formation in liver cancer cells.

Dynamic evolution of MADS-box genes in extant ferns via large-scale phylogenomic analysis.

Introduction: Several studies of MADS-box transcription factors in flowering plants have been conducted, and these studies have indicated that they have conserved functions in floral organ development; MIKC-type MADS-box genes has been proved to be expanded in ferns, however, few systematic studies of these transcription factors have been conducted in non-seed plants. Although ferns and seed plants are sister groups, they exhibit substantial morphological differences. Methods: Here, we clarified the evolution of MADS-box genes across 71 extant fern species using available transcriptome, genome, and gene expression data. Results: We obtained a total of 2,512 MADS-box sequences, ranging from 9 to 89 per species. The most recent common ancestor (MRCA) of ferns contained approximately three type I genes and at least 5-6 type II MADS-box genes. The domains, motifs, expression of type I and type II proteins, and the structure of the both type genes were conserved in ferns as to other land plants. Within type II genes, MIKC*-type proteins are involved in gametophyte development in ferns; MIKCC-type proteins have broader expression patterns in ferns than in seed plants, and these protein sequences are likely conserved in extant seed plants and ferns because of their diverse roles in diploid sporophyte development. More than 90% of MADS-box genes are type II genes, and MIKCC genes, especially CRM1 and CRM6-like genes, have undergone a large expansion in leptosporangiate ferns; the diverse expression patterns of these genes might be related to the fuctional diversification and increased complexity of the plant body plan. Tandem duplication of CRM1 and CRM6-like genes has contributed to the expansion of MIKCC genes. Conclusion or Discussion: This study provides new insights into the diversity, evolution, and functions of MADS-box genes in extant ferns.

Comparison of vonoprazan bismuth-containing triple therapy with quadruple therapy in Helicobacter pylori-infected treatment-naive patients: a prospective multicenter randomized controlled trial.

BACKGROUND AND AIM: Helicobacter pylori infection is linked to various gastrointestinal conditions, such as chronic active gastritis, peptic ulcers, and gastric cancer. Traditional treatment options encounter difficulties due to antibiotic resistance and adverse effects. Therefore, the aim of this study was to explore the effectiveness of a new treatment plan that combines vonoprazan (VPZ), amoxicillin, and bismuth for the eradication of H. pylori. METHODS: A total of 600 patients infected with H. pylori were recruited for this multicenter randomized controlled trial. Patients treated for H. pylori elimination were randomly assigned at a 1:1 ratio to receive 14 days of vonoprazan-based triple therapy (vonoprazan + amoxicillin + bismuth, group A) or standard quadruple therapy (esomeprazole + clarithromycin + amoxicillin + bismuth, group B). Compliance and adverse effects were tracked through daily medication and side effect records. All patients underwent a 13C/14C-urea breath test 4 weeks after treatment completion. RESULTS: Intention-to-treat (ITT) and per-protocol (PP) analyses revealed no substantial differences in H. pylori eradication rates between groups A and B (ITT: 83.7% vs 83.2%; PP: 90.9% vs 89.7%). However, significant differences were observed in the assessment of side effects (13.7% vs 28.6%, P < 0.001). Specifically, group A had significantly fewer "bitter mouths" than group B did (3.7% vs 16.2%, P < 0.001). CONCLUSION: Triple therapy comprising vonoprazan (20 mg), amoxicillin (750 mg), and bismuth potassium citrate (220 mg) achieved a PP eradication rate ≥90%, paralleling standard quadruple therapy, and had fewer adverse events and lower costs (¥306.8 vs ¥645.8) for treatment-naive patients.

Are Osteoblasts Multiple Cell Types? A New Diversity in Skeletal Stem Cells and Their Derivatives.

Only in the past decade have skeletal stem cells (SSCs), a cell type displaying formal evidence of stemness and serving as the ultimate origin of mature skeletal cell types such as osteoblasts, been defined. Here, we discuss a pair of recent reports that identify that SSCs do not represent a single cell type, but rather a family of related cells that each have characteristic anatomic locations and distinct functions tailored to the physiology of those sites. The distinct functional properties of these SSCs in turn provide a basis for the diseases of their respective locations. This concept emerges from one report identifying a distinct vertebral skeletal stem cell driving the high rate of breast cancer metastasis to the spine over other skeletal sites and a report identifying two SSCs in the calvaria that interact to mediate both physiologic calvarial mineralization and pathologic calvarial suture fusion in craniosynostosis. Despite displaying functional differences, these SSCs are each united by shared features including a shared series of surface markers and parallel differentiation hierarchies. We propose that this diversity at the level of SSCs in turn translates into a similar diversity at the level of mature skeletal cell types, including osteoblasts, with osteoblasts derived from different SSCs each displaying different functional and transcriptional characteristics reflecting their cell of origin. In this model, osteoblasts would represent not a single cell type, but rather a family of related cells each with distinct functions, paralleling the functional diversity in SSCs.

Only in the past decade have the stem cells in the skeleton been identified. Here, we discuss a pair of recent reports that identify that skeletal stem cells are actually a family of related cells that each have distinct locations and functions. These site-specific skeletal stem cells account for the signature diseases occurring in different regions of the skeleton. Specifically, one of these stem cells forms the spine and establishes that this stem cell drives the high rate of breast cancer metastasis to the spine over other skeletal sites. There are also at least two skeletal stem cells in the flat bones of the skull, with mutations alerting how these two stem cells "talk" to each other serving as a cause for disorders of premature skull fusion. Despite displaying differences in their function, these stem cells are each united by shared features including a partially shared series marker genes. We also here propose that this diversity at the level of skeletal stem cells translates into a similar diversity in mature skeletal cell types, including osteoblasts. In this model, osteoblasts are not a single cell type, but rather a family of related cells each with distinct functions.

Ribonuclease 4 functions as an intestinal antimicrobial protein to maintain gut microbiota and metabolite homeostasis.

Antimicrobial proteins contribute to host-microbiota interactions and are associated with inflammatory bowel disease (IBD), but our understanding on antimicrobial protein diversity and functions remains incomplete. Ribonuclease 4 (Rnase4) is a potential antimicrobial protein with no known function in the intestines. Here we find that RNASE4 is expressed in intestinal epithelial cells (IEC) including Paneth and goblet cells, and is detectable in human and mouse stool. Results from Rnase4-deficient mice and recombinant protein suggest that Rnase4 kills Parasutterella to modulate intestinal microbiome, thereby enhancing indoleamine-2,3-dioxygenase 1 (IDO1) expression and subsequently kynurenic and xanthurenic acid production in IECs to reduce colitis susceptibility. Furthermore, deceased RNASE4 levels are observed in the intestinal tissues and stool from patients with IBD, correlating with increased stool Parasutterella. Our results thus implicate Rnase4 as an intestinal antimicrobial protein regulating gut microbiota and metabolite homeostasis, and as a potential diagnostic biomarker and therapeutic target for IBD.