Specific Role Research Articles

A minor role for hemispheric specialization in determining pseudoneglect: A pre-registered replication-extension study.

Neurologically intact individuals display a mild asymmetry in spatial attention that can be measured during experimental spatial tasks such as line bisection. Although this phenomenon, known as pseudoneglect, is traditionally explained as the consequence of right hemisphere dominance for visuospatial attention, surmounting evidence suggests this is not its sole or even its most important determinant. For instance, a recent fMRI study in left-handers revealed that rare individuals with a reversed, left hemispheric dominance (LHDS, N=23) also demonstrated left-sided pseudoneglect, although their spatial bias was less marked compared to typically lateralized controls (N=40). The current study sought to replicate and extend these findings in a broader cohort of right-handers (N=75) and left-handers (N=181), while addressing methodological limitations of the original study. Contrary to the predictions of the hemispheric specialization account, pseudoneglect was not reversed in LHDS participants (N=49). However, the pseudoneglect effect was reduced compared to controls with typical cerebral laterality (N=207) due to a population-level randomization of pseudoneglect in the LHDS group. These results align with those of the original study, supporting a multifactorial interpretation of pseudoneglect, with hemisphere specialization as one among many determinants rather than being the predominant cause.

PPARγ modulator predictor (PGMP_v1): chemical space exploration and computational insights for enhanced type 2 diabetes mellitus management.

Peroxisome proliferator-activated receptor gamma (PPARγ) plays a critical role in adipocyte differentiation and enhances insulin sensitivity. In contemporary drug discovery, in silico design strategies offer significant advantages by revealing essential structural insights for lead optimization. The study is guided by two main objectives: (i) a ligand-based approach to explore the chemical space of PPARγ modulators followed by molecular docking ensembles (MDEs) to investigate ligand-binding interactions, (ii) the development of a supervised ML model for a large dataset of compounds targeting PPARγ. Additionally, the combination of chemical space networks with ML models enables the rapid screening and prediction of PPARγ modulators. These modeling analyses will assist medicinal chemists in designing more potent PPARγ modulators. To further enhance accessibility for the scientific community, we developed an online tool, "PGMP_v1," aimed at prospective screening for PPARγ modulators. The tool "PGMP_v1" is available at the provided link https://github.com/Amincheminfom/PGMP_v1 . The integration of these computational methods has uncovered crucial structural motifs that are essential for PPARγ activity, advancing the development of more effective modulators in the future.

PTPA localized in the Golgi apparatus plays an important role in osteoblast differentiation.

Regulatory subunits of protein phosphatase 2A (PP2A) define the substrate and functional specificity of the PP2A holoenzyme within specific organelles. While PP2A regulates osteoblast differentiation, the roles and localization of its regulatory subunits in osteoblasts remain unclear. Here, we identified PTPA, a PP2A regulatory protein, predominantly localized to the Golgi apparatus, closely overlapping with the Golgi marker Giantin. Disruption of the Golgi structure by Brefeldin A caused PTPA to disperse into the cytoplasm. PTPA overexpression inhibited osteoblast differentiation by downregulating key transcriptional regulators. The Golgi-specific localization of PTPA suggests it may influence bone-related protein secretion and maintain Golgi integrity. These findings highlight the critical role of PTPA in osteoblast differentiation and its association with the Golgi apparatus.

The incidence and significance of iliac vein stenosis in patients with deep vein thrombosis.

ObjectiveThe role of iliac vein stenosis (IVS) in the development of DVT is poorly understood. This study determines the incidence of IVS in patients diagnosed with DVT and assesses its impact on presentation and outcomes. Our hypothesis is that the presence of IVS increases the risk of long-term ipsilateral DVT recurrence. MethodsA retrospective study of the electronic medical records of consecutive adult patients treated for lower extremity DVT was performed. Only patients with cross-sectional imaging (CT or MR with intravenous contrast) were included. Patient and DVT characteristics were recorded. Cross-sectional imaging was reviewed for the presence or absence of ipsilateral IVS (≥50%). Patients were divided into 2 groups based on the presence or absence of IVS to compare characteristics and outcomes. Subgroup analyses on patients with provoked DVT, Cancer-related DVT, and unprovoked DVT were performed. ResultsThere were 548 patients with DVT and 32% had evidence of ipsilateral IVS on cross-sectional imaging. There were no significant differences in baseline characteristics or treatment methods between the 2 groups. There was a trend toward patients with IVS having less incidence of PE on presentation (22.9% vs 29.7%, P=0.1) but that difference did not reach statistical significance in the overall comparison. Subgroup analysis in patients with Cancer-related DVT (n=227) showed that patients with IVS were significantly more likely to develop ipsilateral recurrent DVT compared to patients with no IVS (12.9% vs 4.5%, P=0.045). Patients with unprovoked DVT with IVS had significantly lower PE on presentation compared to patients with unprovoked DVT without IVS (24.2% vs 39.8%, P<0.03). ConclusionIpsilateral ≥50% IVS is present in approximately a third of patients presenting with DVT. The presence of IVS seems to play a differential role in ipsilateral DVT recurrence and prevention of pulmonary embolization in different groups of patients presenting with DVT.

Subtype-specific role for Jagged1 in promoting or inhibiting breast tumor formation

Notch signaling is altered in breast cancer. Recent studies highlighted both tumor-suppressive and oncogenic roles for Notch in this tissue. The function of Jagged1, the most highly expressed Notch ligand in the mammary gland, is not well defined. Here we report that deletion of Jagged1 in the mammary epithelium of virgin mice led to expansion of the mammary stem cell (MaSC) compartment and defective luminal differentiation associated with decreased expression of the progesterone receptor (PR). In contrast, deletion of Jagged1 in alveolar cells of pregnant mice had no effect on alveolar and lactogenic differentiation or post-lactational involution. Interestingly, deletion of Jagged1 promoted mouse mammary tumor formation from luminal cells but suppressed them from basal cells, associated with downregulation of Notch target genes Hey1 and Hey2, respectively. In agreement with mouse experiments, high expression of JAG1 and HEY1 are associated with better overall survival among patients with luminal tumors, whereas high expression of JAG1 and HEY2 are both associated with worse overall survival in basal subtype of human breast cancer. These results identified Jagged1 as an important regulator of mammary epithelial hierarchy and revealed differential roles of Jagged1-mediated Notch signaling in different subtypes of breast cancer arising from distinct cell types.

Two homologous Zn2Cys6 transcription factors play crucial roles in host specificity of Colletotrichum orbiculare by controlling the expression of cucurbit-specific virulence effectors.

Fungal plant pathogens preferentially express a set of effector genes at specific infection stages to successfully colonize the host. However, it remains unclear how effector gene expression is regulated during host infection. This study identified a Zn2Cys6 transcription factor, TFV1 (Transcription Factor for Virulence 1), whose deletion weakened virulence of Colletotrichum orbiculare on its cucurbit hosts. The additional deletion of a TFV1 paralog gene, TVL1 (TFV1-like 1), resulted in a further reduction in virulence on the cucurbits. Notably, TFV1 TVL1 double mutants retained wild-type virulence on the Solanaceae host Nicotiana benthamiana. Expression of putative effector genes, including four cucurbit host-specific virulence effectors (effector protein for cucurbit infection, EPC1-4), was commonly downregulated in the TFV1 knockout mutants. Yeast one-hybrid assays suggested that TFV1 binds to the putative promoter regions of EPC2, EPC3, and EPC4, indicating the importance of TFV1 for the induced expression of key effector genes in cucurbit infection. Among the effector-like genes whose expression was affected by TVL1 deletion, a novel LysM effector gene, EPC5, was identified as being specifically required for virulence on cucurbit hosts. Our study extends the knowledge of the regulatory mechanisms governing host- and stage-specific effectors in C. orbiculare.

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.

Xenopus laevis neural stem progenitor cells exhibit a transient metabolic shift toward glycolysis during spinal cord regeneration

Spinal cord injury (SCI) results in severe disruption of communication between the brain and body, causing motor, sensory, and autonomic dysfunctions. While SCI in mammals leads to permanent impairment due to limited regenerative capacity, certain non-mammalian species, such as Xenopus laevis larval stages, exhibit remarkable regenerative abilities. During Xenopus laevis spinal cord regeneration, neural stem precursor cells (NSPCs) surrounding the central canal rapidly proliferate in response to SCI, compensating for cellular loss, restoring canal continuity, and generating new neurons to reestablish lost connections. It has been described that mitochondria and cellular metabolism play essential roles in stem cell proliferation, self-renewal, and differentiation. However, the mitochondrial and cellular metabolic response during spinal cord regeneration remains unexplored. This study uses electron and confocal microscopy to investigate the NSPCs mitochondrial response in Xenopus laevis following SCI. We observed that mitochondria exhibit a rapid and transient response after SCI, characterized by a disruption of the mitochondrial localization, a decrease in mitochondrial number per cell section, and an increase in mitochondrial area and circularity. Furthermore, mitochondria adopted a swollen phenotype, which did not impair mitochondrial function or cellular energy balance. This morphological shift was accompanied by a transient decrease in the mitochondrial membrane potential and a metabolic switch favoring glycolysis. Therefore, these findings demonstrate that a transient metabolic shift toward glycolysis occurs during spinal cord regeneration.

The role of Anti-Müllerian hormone in women health.

Anti-Müllerian hormone (AMH), also known as Müller duct inhibitory factor and primarily known for its role in sexual differentiation. In female fetuses, AMH production by granulosa cells begins around the 36th week of gestation and continues in women until menopause. It is becoming more significant in the endocrine and gynecological diagnosis of adult women. The suppressive effect of AMH on follicle-stimulating hormone (FSH)-induced aromatase production likely plays a role in hyperandrogenism in polycystic ovary syndrome (PCOS) and may increase insulin resistance. Female adolescent with type 1 diabetes (T1D) have an increased likelihood of developing PCOS, but it is not known whether they also show elevated AMH levels. The elevated AMH levels observed in prepubertal girls with T1D suggest that there are more small follicles in their ovaries, probably in response to insulin treatment. Elevated levels of androgens and anti-Müllerian hormone have been previously reported in non-pregnant women with diabetes. The increased AMH concentrations can be associated with reduced systemic inflammation [lower c-reactive protein (CRP) values], irrespective of the type of diet and greater insulin sensitivity in old obese males. AMH can also serve as a valuable marker for granulosa cell tumors (folliculomas) and their recurrence. In these clinical scenarios, AMH levels can be significantly elevated and correspond with the size of the tumor.

Disproportionate vulnerability to and unique aggregation pattern of non-AIDS comorbidities among women with HIV in China

Abstract Background Whether and how sex plays differential roles in aging-related multimorbidity among people with HIV (PWH) is poorly characterized. Methods We included 2479 PWH and 5376 people without HIV (PWoH) from the baseline assessment of the Comparative HIV and Aging Research in Taizhou (CHART) cohort. Ten non-AIDS comorbidities (NACM) were investigated. Multiple logistic regression was used to assess the correlates of multimorbidity (defined as the coexistence of ≥2 NACM). Multimorbidity patterns were identified through hierarchical cluster analysis. Results The prevalence of multimorbidity was higher in PWH than in PWoH (74.6% vs. 66.9%, p &amp;lt; 0.001). This difference was particularly pronounced in women in each of the age groups from 18 through 59 years and among men in each of the age groups from 18 through 49 years. A significant interaction between sex and HIV on multimorbidity was identified (p &amp;lt; 0.001), with the strength of the association between HIV infection and multimorbidity being stronger in women than in men. Women with HIV presented a unique aggregation pattern of multimorbidity, where neuropsychiatric disorders (depression, neurocognitive impairment) clustered with cardiometabolic diseases. In contrast, all men and women without HIV manifested a similar multimorbidity pattern, where depression and neurocognitive impairment were clustered with hematologic abnormalities but not with cardiometabolic diseases. Conclusions Earlier onset and higher burden of multimorbidity in PWH, as well as disproportionate vulnerability to and unique multimorbidity pattern among women with HIV, underscore the urgent need for early and sexually-oriented integrative interventions and health services targeting multimorbidity in PWH.

Single-cell RNA sequencing revealed PPARG promoted osteosarcoma progression: based on osteoclast proliferation

BackgroundOsteosarcoma (OS) is one of the most common primary malignant bone tumors, primarily originating from mesenchymal tissue. It is notorious for its high invasiveness, high disability rate, high mortality rate, and poor prognosis. In most primary and metastatic malignant tumors, bone destruction can promote cancer progression, which is closely related to osteoclast activation and the imbalance between osteoblasts and osteoclasts. A large number of studies confirmed that osteoclasts are an important part of OS, which play an active role in destroying bone homeostasis and promoting the progress of OS. Therefore, we conducted a detailed study of osteoclasts at the single cell level, aiming to find new OS therapeutic targets to prevent tumor progression and local spread.MethodsWe analyzed the single-cell sequencing data of OS patients and usedMonocle2, Cytotrace, and Slingshot software to analyze the pseudo-sequential trajectory during OS progression. CellChat was used to reveal the communication between cells. PySCENIC was used to identify active transcription factors in osteoclasts. Finally, we further demonstrated the results by RT-qPCR analysis, CCK-8 assay, wound healing assay, Transwell assay, etc.ResultsThrough the analysis of single-cell sequencing data in OS, we identified a highly specific subgroup, C2MKI67+ Osteoclast. The key signaling pathway APP and the top 1 transcription factor PPARG in this subgroup played essential roles in osteoclast proliferation and differentiation. Given the pivotal role of osteoclasts in OS progression, we speculated that these signaling pathways and transcription factors could emerge as novel therapeutic targets, offering innovative strategies for OS treatment.ConclusionThis study enhanced our understanding of OS and osteoclasts through scRNA-seq. Furthermore, we discovered that PPARG amplifies osteoclast activation and proliferation, resulting in excessive bone resorption and degradation of the bone matrix, thereby creating a favorable environment for tumor cell proliferation and growth. By innovatively targeting PPARG, it affected osteoclast proliferation and thus affected tumor progression; this work offered new insights and directions for the clinical treatment of OS patients.

Integrated transcriptomic analysis of human induced pluripotent stem cell-derived osteogenic differentiation reveals a regulatory role of KLF16.

Osteogenic differentiation is essential for bone development, metabolism, and repair; however, the underlying regulatory relationships among genes remain poorly understood. To elucidate the transcriptomic changes and identify novel regulatory genes involved in osteogenic differentiation, we differentiated mesenchymal stem cells (MSCs) derived from 20 human iPSC lines into preosteoblasts (preOBs) and osteoblasts (OBs). We then performed transcriptome profiling of MSCs, preOBs and OBs. The iPSC-derived MSCs and OBs showed similar transcriptome profiles to those of primary human MSCs and OBs, respectively. Differential gene expression analysis revealed global changes in the transcriptomes from MSCs to preOBs, and then to OBs, including the differential expression of 840 genes encoding transcription factors (TFs). TF regulatory network analysis uncovered a network comprising 451 TFs, organized into five interactive modules. Multiscale embedded gene co-expression network analysis (MEGENA) identified gene co-expression modules and key network regulators (KNRs). From these analyses, KLF16 emerged as an important TF in osteogenic differentiation. We demonstrate that overexpression of Klf16 in vitro inhibited osteogenic differentiation and mineralization, while Klf16 +/- mice exhibited increased bone mineral density, trabecular number, and cortical bone area. Our study underscores the complexity of osteogenic differentiation and identifies novel regulatory genes such as KLF16 , which plays an inhibitory role in osteogenic differentiation both in vitro and in vivo.

A Phonology of Vowel Insertion to Malay Cluster Consonants by Native Speaker of Kashmir

This study explores the phonetic intricacies of the Kashmiri sound system, characterised by a rich inventory of vowels and consonants, resembling other Indo-Aryan languages. Kashmiri syllables typically comprise a vowel accompanied by one or two optional consonants, contributing to the distinct melodic quality of Kashmiri speech. Notably, Kashmiri exhibits a variety of short and long vowels, where vowel length and nasalisation play pivotal roles in word meaning differentiation, enriching the phonetic landscape. This qualitative researchfocuses on vowel insertion processes into Malay consonant clusters by native Kashmiri speakers from graduate students of the National University of Malaysia,aiming to identify instances of epenthesis in Malay words with consonant clusters. Employing the Optimality Theory framework, the study analyses these processes and elucidates the hierarchy of constraints shaping Kashmiri speakers' Malay communication. Findings suggest prevalent vowel insertion in word /draf/ become [dəraf], /span/ become [səpan], etc. and phoneme substitution among native Kashmiri speakers, particularly in Malay words with consonant clusters. This study underscores the significance of phonological processes in interlinguistic communication among phonology-native Kashmiri speakers.

Enhancer-driven Shh signaling promotes glia-to-mesenchyme transition during bone repair

Plp1-lineage Schwann cells (SCs) of peripheral nerve play a critical role in vascular remodeling and osteogenic differentiation during the early stage of bone healing, and the abnormal plasticity of SCs would jeopardize the bone regeneration. However, how Plp1-lineage cells respond to injury and initiate the vascularized osteogenesis remains incompletely understood. Here, by employing single-cell transcriptional profiling combined with lineage-specific tracing models, we uncover that Plp1-lineage cells undergoing injury-induced glia-to-MSCs transition contributed to osteogenesis and revascularization in the initial stage of bone injury. Importantly, our data demonstrated that the Sonic hedgehog (Shh) signaling was responsible for the transition process initiation, which was strongly activated by c-Jun/SIRT6/BAF170 complex-driven Shh enhancers. Collectively, these findings depict an injury-specific niche signal-mediated Plp1-lineage cells transition towards Gli1+ MSCs and may be instructive for approaches to promote bone regeneration during aging or other bone diseases.

Unveiling the role of miRNAs in Diminished Ovarian Reserve: an in silico network approach

MicroRNAs (miRNAs) have acquired an increased recognition to unravel the complex molecular mechanisms underlying Diminished Ovarian Reserve (DOR), one of the main responsible for infertility. To investigate the impact of miRNA profiles in granulosa cells and follicular fluid, crucial players in follicle development, this study employed a computational network theory approach to reconstruct potential pathways regulated by miRNAs in granulosa cells and follicular fluid of women suffering from DOR. Available data from published research were collected to create the FGC_MiRNome_MC, a representation of miRNA target genes and their interactions. 365 hubs were identified within the network, representing potential key regulators, and 210 nodes that act as both hubs and bottlenecks (H&BN nodes), suggesting that they may control the information flow within the network. GO enrichment analysis of the 210 H&BN nodes revealed their involvement in fundamental cellular processes relevant to ovarian function. In particular, the cluster analysis identified several shared pathways between cluster 1 and cluster 2 involved in the RAS/MAPK pathway, which plays a critical role in cell proliferation, differentiation and survival. These findings suggest that miRNAs play a significant role in DOR and highlight the potential of the RAS/MAPK pathway as a target for further investigation. Additionally, the genes identified as both hubs and bottlenecks revealed interesting connections to reproductive health in KO mice models. This in silico approach provides valuable insights into potential biomarkers and therapeutic targets for age-related reproductive disorders.

Iron Drives Eosinophil Differentiation in Allergic Airway Inflammation Through Mitochondrial Metabolic Adaptation.

Eosinophils play a crucial role as effector cells in asthma pathogenesis, with their differentiation being tightly regulated by metabolic mechanisms. While the involvement of iron in various cellular processes is well known, its specific role in eosinophil differentiation has largely remained unexplored. This study demonstrates that iron levels are increased during the differentiation process from eosinophil progenitorsto mature and activated eosinophils in the context of allergic airway inflammation. Through experiments involving iron chelators, supplements, and iron-deficient or iron-enriched diets, the indispensable role of iron in eosinophil lineage commitment both in vitro and in vivo is demonstrated. Remarkably, iron chelation effectively suppresses eosinophil differentiation and alleviates airway inflammation in a house dust mite(HDM)-induced mouse model of allergic asthma. Mechanistically, iron promotes the expression of transcription factors that enforce eosinophil differentiation, and maintains mitochondrial metabolic activities, leading to specific metabolic shifts within the tricarboxylic acid (TCA) cycle, with succinate promoting eosinophil differentiation. Overall, this study highlights the function of iron and underlying metabolic mechanisms in eosinophil differentiation, providing potential therapeutic strategies for asthma control.

LD-transpeptidase-mediated cell envelope remodeling enables developmental transitions and survival in Coxiella burnetii and Legionella pneumophila.

Coxiella burnetii and Legionella pneumophila are two phylogenetically related bacterial pathogens that exhibit extreme intrinsic resistance when they enter into a dormancy-like state. This enables both pathogens to survive extended periods in growth-limited environments. Survival is dependent upon their ability to undergo developmental transitions into two phenotypically distinct variants, one specialized for intracellular replication and another for prolonged survival in the environment and host. We currently lack an understanding of the mechanisms that mediate these developmental transitions. Here, we performed peptidoglycan (PG) glycoproteome analysis and showed significant enrichment of PG structures catalyzed by LD-transpeptidases (LDTs) in the survival variants of C. burnetii and L. pneumophila. This is supported by the upregulation of LDTs, resulting in susceptibility to carbapenem antibiotics. Furthermore, deletion of the most upregulated LDT, lpg1386, in L. pneumophila significantly changes PG architecture, survival, and susceptibility to antibiotics. Significantly regulated by RpoS, a stationary-phase sigma factor, LDT-dependent PG remodeling is differentially activated by the host intracellular growth environment compared to axenic culture. In addition, β-barrel tethering, a newly discovered mechanism of LDT-mediated cell envelope stabilization, seems not to be specific to the survival variants. Interestingly, an outer membrane (OM) long-chain fatty acid transporter (Lpg1810) is tethered to PG in L. pneumophila. Collectively, these findings show that LDT-mediated PG remodeling is a major determinant of developmental transitions and survival in C. burnetii and L. pneumophila. Understanding this mechanism might inform new therapeutic approaches for treating chronic infections caused by these pathogens, as well as suggest new methods to decontaminate environmental reservoirs during outbreaks.IMPORTANCECoxiella burnetii and L. pneumophila cause Q Fever and Legionnaire's disease in humans, respectively. There is a lack of effective treatments for fatal chronic infections caused by these pathogens, particularly chronic Q Fever. These bacteria survive long term in nutrient-limited environments by differentiating into phenotypically distinct survival variants. Our study revealed that LDTs, a group of PG remodeling enzymes, play a prominent role in the phenotypic differentiations of these bacteria. We show that LDT-targeting carbapenems are effective against the survival variants, thus demanding the exploration of carbapenems for treating chronic infections caused by these pathogens. We report the tethering of a unique OM fatty acid transporter to PG in L. pneumophila that could indicate a novel function of tethering, that is, the uptake of nutrient substrates. Homologs of this transporter are widely present in the Methylobacteriaceae family of bacteria known to survive in water systems like Legionella, thus suggesting a potentially conserved mechanism of bacterial survival in nutrient-limited environments.

ANXA2 promotes chondrocyte differentiation and fracture healing by regulating the phosphorylation of STAT3 and PI3K/AKT signaling pathways.

Fractures are common and serious skeletal injuries, and accelerating their healing while alleviating patient suffering remains a clinical challenge. Annexin A2 (ANXA2) is a widely distributed, calcium-dependent, phospholipid-binding protein involved in bone remodeling. However, its role in chondrocyte differentiation and endochondral ossification remains unclear. In this study, we found that ANXA2 is expressed in chondrocytes during growth plate development and fracture healing, as well as during chondrocyte differentiation and maturation in vitro, with its highest expression occurring in the most active differentiation phase. Moreover, ANXA2 knockdown inhibited chondrocyte differentiation, while its overexpression significantly promoted it. We also demonstrated that ANXA2 regulates the chondrogenic and hypertrophic differentiation by mediating the phosphorylation and nuclear translocation of STAT3, as well as activating the PI3K/AKT pathway. Finally, recombinant ANXA2 protein was injected into the tibial fracture sites of mice, verifying its role in promoting endochondral ossification during fracture healing. In conclusion, our study shows that ANXA2 promotes chondrocyte differentiation, partially through the STAT3 and PI3K/AKT pathways. These findings provide insights that could aid in developing new therapies to enhance fracture healing.

DOP072 The IL1-dependent transcription factor MEOX1 as a driver of differentiation programs in ACKR1+ endothelial cells of inflammatory bowel disease granulation tissue

Abstract Background Activated endothelial cells (ECs) are expanded in IBD tissue and express ACKR11, a chemokine receptor known to mark venular endothelium and enable immune cell trafficking. ACKR1+ ECs have been reported in diseases associated with inflammation and/or fibrosis2, although their role in stromal differentiation is unclear. We investigated the relationship between IL1 and inflammation in IBD and identified an IL1-dependent transcription factor (TF), MEOX1, known to regulate fibrosis in cardiac ischemia3 that is associated with IBD ulcers and expressed in ACKR1+ ECs. Methods We assessed IL-1 bioactivity and performed matched RNA-seq on a cohort of Crohn’s disease (n=23), ulcerative colitis (n=18) and non-IBD (n=17) patients. We performed scRNA-seq of n=208 very early onset (VEO)IBD and control intestinal patient samples. RNA-scope was performed in IBD tissue with/without ulcers. Primary colonic ECs and human umbilical vein (HUV)ECs were stimulated with IL1B +/- TGFB +/- JQ1 (a BRD4 inhibitor that knocked down IL1/MEOX1 driven cardiac fibrosis) followed by qPCR, bulk/scRNA-seq. Results In the paired IL1 proteomic and RNA-seq analyses of IBD tissue, we identified an IL1 and ulcer-specific gene signature which included the TF MEOX1. In scRNA seq analysis, MEOX1 was expressed exclusively in ECs (most robustly in ACKR1+ ECs, which co-expressed the IL1 receptor IL1R1) (Fig 1A). ACKR1+MEOX1+IL1R1+ ECs were significantly expanded in inflamed VEOIBD, especially in those with deep ulcers and IL10R deficiency, and exhibited hallmarks of cell cycle arrest, e.g. expression of CDKN1A (Fig 1B and data not shown). RNA-scope revealed abundant ACKR1+MEOX1+IL1R1+ EC structures specifically in granulation tissue (Fig 1C). In primary colonic ECs, IL1B stimulation induced CDKN1A, unlike TGFB which induced a proliferation/apoptosis phenotype (Fig 1D). In HUVECs, IL1B induced a spindle-shape/fibroblastic EC morphology and ACKR1/MEOX1 expression (data not shown). scRNA-seq revealed an IL1-induced cluster defined by ACKR1, CDKN1A and chemotactic/collagen-producing gene programs, eliminated upon addition of JQ1 (Fig 1E; data not shown). Conclusion ACKR1+ ECs define IBD granulation tissue and co-express IL1R1 as well as the TF MEOX1, which may prove to be a driver of differentiation programs downstream of IL1 signaling at the EC niche that may lead to fibrosis. In silico and in vitro data suggest IL1-driven EC programs are characterized by cell cycle arrest signatures. We hypothesize that the IL1/MEOX1 pathway in ACKR1+ ECs may represent a novel molecular mechanism related to ulcer biology and wound repair in IBD with potential therapeutic implications.

MOTS-c Impact on Muscle Cell Differentiation and Metabolism Across Fiber Types.

MOTS-c belongs to a group of mitochondrial peptides involved in metabolic processes in the body. This peptide has garnered increasing attention since its discovery in 2015 because of its potential to ameliorate metabolic parameters in animals with diabetes or insulin resistance. MOTS-c is involved in muscle metabolism; however, little is known about its role in fiber differentiation. We conducted a study to explore the effect of MOTS-c on cellular processes using the C2C12 and L6 cell lines, representing different metabolic types of muscle fibers. The research methods were real-time PCR, Western blot, and lipid accumulation measurement. Notably, our investigations revealed that MOTS-c increased the survival of C2C12 cells at doses of 10 and 100 nM (p<0.01) and stimulated the phosphorylation of extracellular signal-regulated kinase within 5 min of incubation (p<0.05). Remarkably, these effects were not observed in L6 cells; however, both cell lines showed a reduced rate of proliferation. Furthermore, MOTS-c promotes the differentiation of C2C12 cells by increasing the expression of muscle regulatory factors, but it does not produce such an effect in L6 cells. Additionally, cells were treated with physiological concentrations of free fatty acids and MOTS-c, unveiling an augmentation in lipid accumulation observed in L6 cells and a decrease in lipid accumulation in C2C12 cells. In conclusion, our findings have suggested a diverse response to MOTS-c depending on the type of muscle fibers, particularly in the domains of survival, cell differentiation, and lipid accumulation.