Biology subjects

Civitelli, R.

Publications and source records attributed to Civitelli, R..

6 recordsLinked to original sources

bioRxiv2025

N-cadherin in osteolineage cells restrains breast cancer cell growth via inhibition of a PI3K-dependent, Tgf-β1-driven feed-forward loop

Tumor growth and metastases are affected by interactions between tumor and microenvironment cells. We have reported the presence of Sp7-positive cells with an osteogenic signature in primary mouse breast cancer, where they stimulate tumor growth; and genetic ablation of Cdh2 (encoding N-cadherin) in these cells enhances their pro-tumorigenic action. To study the molecular mechanisms of this biologic system, we used MC3T3 cells, phenotypically similar to tumor associated osteolineage cells. Ablation of Cdh2 in MC3T3 cells enhances PI3K-Akt-{beta}-catenin signaling in response to transforming growth factor-{beta}1 (Tgf-{beta}1), resulting in increased production of Tgf-{beta}1. Interference with PI3K activity is mediated by N-cadherin binding to PI3K components, p85 and p100, resulting in reduced activation of PI3K-Akt-{beta}-catenin signaling. Downstream, Cdh2 ablation enhances Tgf-{beta}1-induced binding of Sp1 and Lef-1 to the Tgfb1 promoter, leading to increased promoter activity and enhanced Tgf-{beta}1 production. This is associated with miR-21 up-regulation and decreased expression of Pten, a PI3K inhibitor. MC3T3 cells promote growth of breast cancer cells (BCC) when co-cultured in vitro or co-injected in mouse mammary fat pad, and Cdh2-deficiency enhances this pro-tumorigenic effect. Notably, genetic ablation of the Tgf-{beta}1 receptor subunit, Tgfbr1, in BCC abrogates the pro-tumorigenic action of MC3T3 cells and its enhancement by Cdh2 ablation. Finally, Sp7-driven Tgfbr1 ablation in mice also reduces the growth of BCC in the mammary fat pad. Thus, autocrine Tgf-{beta}1 production via PI3K-Akt-{beta}-catenin signaling is a key mechanism by which osteolineage cells promote BCC growth, an action restrained by Ncad via interference with PI3K components. HighlightsO_LIIn tumor-associated osteolineage cells, N-cadherin reduces the growth of breast tumors; it also inhibits Tgf-{beta}1-activated PI3K/AKT/{beta}-catenin signaling C_LIO_LITgf-{beta}1 produced by tumor microenvironment cells stimulates breast cancer cell growth and further autocrine production of Tgf-{beta}1 C_LIO_LIThe anti-tumorigenic action of N-cadherin is mediated by a braking effect on a Tgf-{beta}1-driven, pro-tumorigenic, feed-forward cycle between microenvironment and tumor cells. C_LI

cancer biology↗

bioRxiv2024

Increased bone inflammation in type 2 diabetes and obesity correlates with Wnt signaling downregulation and reduced bone strength

Type 2 diabetes (T2D) and obesity (OB) are associated with chronic low-grade inflammation and increased fracture risk. In vitro studies showed that inflammation induces bone erosion and inhibits bone formation by increasing Wnt canonical pathway inhibitors. However, the impact of inflammation on Wnt pathway regulation and bone quality in T2D and OB remains unclear. To this end, we studied 63 postmenopausal women (age >65 years) undergoing hip replacement for osteoarthritis. Among these women, 19 had T2D and OB (HbA1c 6.8{+/-}0.79%; BMI 29.9{+/-}5.2 kg/m2), 17 had OB but they were normoglycemic (BMI 32.5{+/-}5.4 kg/m2), and 27 served as controls (BMI 23.1{+/-}5.5 kg/m2). Serum inflammatory cytokines by automated immunoassay (ELLA), revealed higher TNF- (p=0.0084) and lower adiponectin (p=0.0402) in T2D, and higher IL-6 (p=0.0003) levels in OB vs controls. Gene expression analysis of trabecular bone showed increased TNF- (p=0.0019) and SFRP5 (p=0.0084) in T2D vs controls. IL-10 was lower in both T2D (p=0.0285), and OB (p=0.0324), while adiponectin (ADIPOQ) was only lower in T2D (p=0.0041) vs controls. Interestingly, the Wnt inhibitor SOST was higher in T2D (p<0.0001) and OB (p<0.0001) vs controls. Conversely, WNT10B mRNA levels were lower in T2D (p=0.0071) and in OB (p=0.0196) vs controls, while LEF-1 were only lower in T2D (p=0.0009). WNT5A (p=0.0025) and GSK3{beta} (p=0.0003) mRNA levels were higher only T2D vs controls. Importantly, TNF- mRNA levels positively correlated with SOST (r=0.5121, p=0.0002), WNT5A (r=0.3227, p=0.0396) and GSK3{beta} (r=0.3789, p=0.0146) mRNA levels, but negatively correlated with WNT10B (r=0.3844, p=0.0188) and LEF-1(r=-0.3310, p=0.0322) mRNA levels. Conversely, IL-10 was negatively correlated with SOST mRNA levels (r=0.3100, p=0.0457). ADIPOQ was negatively correlated with SOST (r=-0.3864, p=0.0105) and WNT5A (r=-0.3025, p=0.0515) mRNA levels. Moreover, SFRP5 was negatively correlated with LEF-1 mRNA levels (r=0.3991, p=0.0131). Finally, serum levels of TNF- (r=-0.3473, p=0.0352) and IL-6 (r=-0.3777, p=0.0302) negatively correlated with Youngs Modulus, an index of bone strength. These findings suggest that increased inflammation in bone of subjects with T2D and obesity is negatively associated with Wnt pathway and bone strength, shedding light on pathophysiology of bone impairment in T2D and obesity.

biochemistry↗

bioRxiv2024

Six drivers of aging identified among genes differentially expressed with age

Many studies have compared gene expression in young and old samples to gain insights on aging, the primary risk factor for most major chronic diseases. However, these studies only describe associations, failing to distinguish drivers of aging from compensatory geroprotective responses and incidental downstream effects. Here, we introduce a workflow to characterize the causal effects of differentially expressed genes on lifespan. First, we performed a meta-analysis of 25 gene expression datasets comprising samples of various tissues from healthy, untreated adult mammals (humans, dogs, and rodents) at two distinct ages. We ranked each gene according to the number of distinct datasets in which the gene was differentially expressed with age in a consistent direction. The top age-upregulated genes were TMEM176A, EFEMP1, CP, and HLA-A; the top age-downregulated genes were CA4, SIAH, SPARC, and UQCR10. Second, the effects of the top ranked genes on lifespan were measured by applying post-developmental RNA interference of the corresponding ortholog in the nematode C. elegans (two trials, with roughly 100 animals per genotype per trial). Out of 10 age-upregulated and 9 age-downregulated genes that were tested, two age-upregulated genes (csp-3/CASP1 and spch-2/RSRC1) and four age-downregulated genes (C42C1.8/DIRC2, ost-1/SPARC, fzy-1/CDC20, and cah-3/CA4) produced significant and reproducible lifespan extension. Notably, the data do not suggest that the direction of differential expression with age is predictive of the effect on lifespan. Our study provides novel insight into the relationship between differential gene expression and aging phenotypes, pilots an unbiased workflow that can be easily repeated and expanded, and pinpoints six genes with evolutionarily conserved, causal roles in the aging process for further study. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=169 HEIGHT=200 SRC="FIGDIR/small/606402v1_ufig1.gif" ALT="Figure 1"> View larger version (33K): org.highwire.dtl.DTLVardef@89cc31org.highwire.dtl.DTLVardef@bcd98eorg.highwire.dtl.DTLVardef@6f2b40org.highwire.dtl.DTLVardef@807e27_HPS_FORMAT_FIGEXP M_FIG C_FIG

genetics↗

bioRxiv2024

Connexin43 in mesenchymal lineage cells regulates body adiposity and energy metabolism in mice

Connexin43 (Cx43) is the most abundant gap junction protein present in the mesenchymal lineage. In mature adipocytes, Cx43 mediates white adipose tissue (WAT) "beiging" in response to cold exposure and maintains the mitochondrial integrity of brown adipose tissue (BAT). We found that genetic deletion of Gja1 (Cx43 gene) in cells that give rise to chondro-osteogenic and adipogenic precursors driven by the Dermo1/Twist2 promoter leads to lower body adiposity and partial protection against the weight gain and metabolic syndrome induced by a high fat diet (HFD) in both sexes. These protective effects from obesogenic diet are related to increased locomotion, fuel utilization, energy expenditure, non-shivering thermogenesis, and better glucose tolerance in conditionally Gja1 ablated mice. Accordingly, Gja1 mutant mice exhibit reduced adipocyte hypertrophy, partially preserved insulin sensitivity, increased BAT lipolysis and decreased whitening under HFD. This metabolic phenotype is not reproduced with more restricted Gja1 ablation in differentiated adipocytes, suggesting that Cx43 has a hitherto unknown function in adipocyte progenitors or other targeted cells, resulting in restrained energy expenditures and fat accumulation. These results disclose an hitherto unknown action of Cx43 in adiposity, and offer a promising new pharmacologic target for improving metabolic balance in diabetes and obesity. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=157 HEIGHT=200 SRC="FIGDIR/small/574415v1_ufig1.gif" ALT="Figure 1"> View larger version (72K): org.highwire.dtl.DTLVardef@1ade7d3org.highwire.dtl.DTLVardef@4edbd7org.highwire.dtl.DTLVardef@1431c1borg.highwire.dtl.DTLVardef@ea6bbb_HPS_FORMAT_FIGEXP M_FIG C_FIG

physiology↗

bioRxiv2022

Loading-Induced Bone Formation is Mediated by Wnt1 Induction in Osteoblast-Lineage Cells

Mechanical loading on the skeleton stimulates bone formation. Although the exact mechanism underlying this process remains unknown, a growing body of evidence indicates that the Wnt signaling pathway is necessary for the skeletal response to loading. Recently, we showed that Wnts produced by osteoblast lineage cells mediate the osteo-anabolic response to tibial loading in adult mice. Here, we report that Wnt1 specifically plays a crucial role in mediating the mechano-adaptive response to loading. Independent of loading, short-term loss of Wnt1 in the Osx-lineage resulted in decreased cortical bone area in the tibias of 5-month old mice. In females, strain-matched loading enhanced periosteal bone formation in Wnt1F/F controls, but not in Wnt1F/F; OsxCreERT2 knockouts. In males, strain-matched loading increased periosteal bone formation in both control and knockout mice; however, the periosteal relative bone formation rate was 65% lower in Wnt1 knockouts versus controls. Together, these findings show that Wnt1 supports adult bone homeostasis and mediates the bone anabolic response to mechanical loading.

cell biology↗

bioRxiv2018

ATRAID, a genetic factor that regulates the clinical action of nitrogen-containing bisphosphonates on bone.

Nitrogen-containing bisphosphonates (N-BPs), such as alendronate, are the most widely prescribed medications for diseases involving bone, with nearly 200 million prescriptions written annually. Recently, widespread use of N-BPs has been challenged due to the risk of rare but traumatic side effects such as atypical femoral fracture (AFFs) and osteonecrosis of the jaw (ONJ). N-BPs bind to and inhibit farnesyl diphosphate synthase (FDPS), resulting in defects in protein prenylation. Yet it remains poorly understood what other cellular factors might allow N-BPs to exert their pharmacological effects. Here, we performed genome-wide studies in cells and patients to identify the poorly characterized gene, ATRAID. Loss of ATRAID function results in selective resistance to N-BP-mediated loss of cell viability and the prevention of alendronate-mediated inhibition of prenylation. ATRAID is required for alendronate inhibition of osteoclast function, and ATRAID-deficient mice have impaired therapeutic responses to alendronate in both postmenopausal and senile (old age) osteoporosis models. Lastly, we performed exome sequencing on patients taking N-BPs that suffered ONJ or an AFF. ATRAID is one of three genes that contain rare non-synonymous coding variants in patients with ONJ or AFF that is also differentially expressed in poor outcome groups of patients treated with N-BPs. We functionally validated this patient variation in ATRAID as conferring cellular hypersensitivity to N-BPs. Our work adds key insight into the mechanistic action of N-BPs and the processes that might underlie differential responsiveness to N-BPs in people. One Sentence SummaryATRAID is essential for responses to the commonly prescribed osteoporosis drugs nitrogen-containing bisphosphonates. OverlineBONE

genomics↗