Elucidating the mechano-molecular dynamics of TRAP activity using CRISPR/Cas9 mediated fluorescent reporter mice.

Osteoclasts are essential for bone remodeling by adapting their resorptive activity in response to their mechanical in vivo environment. However, the molecular mechanisms underlying this process remain unclear. Here, we demonstrated the role of tartrate-resistant acid phosphatase (TRAP, Acp5), a key enzyme secreted by osteoclasts, in bone remodeling and mechanosensitivity. Using CRISPR/Cas9 reporter mice, we demonstrated bone cell reporter (BCRIbsp/Acp5) mice feature fluorescent TRAP-deficient osteoclasts and examined their activity during mechanically driven trabecular bone remodeling. Although BCRIbsp/Acp5 mice exhibited trabecular bone impairments and reduced resorption capacity in vitro, RNA sequencing revealed unchanged levels of key osteoclast-associated genes such as Ctsk, Mmp9, and Calcr. These findings, in conjunction with serum carboxy-terminal collagen crosslinks (CTX) and in vivo mechanical loading outcomes collectively indicated an unaltered bone resorption capacity of osteoclasts in vivo. Furthermore, we demonstrated similar mechanoregulation during trabecular bone remodeling in BCRIbsp/Acp5 and wild-type (WT) mice. Hence, this study provides valuable insights into the dynamics of TRAP activity in the context of bone remodeling and mechanosensation.

A mimetic peptide of ACE2 protects against SARS-CoV-2 infection and decreases pulmonary inflammation related to COVID-19.

Since human angiotensin-converting enzyme 2 (ACE2) serves as a primary receptor for SARS-CoV-2, characterizing ACE2 regions that allow SARS-CoV-2 to enter human cells is essential for designing peptide-based antiviral blockers and elucidating the pathogenesis of the virus. We identified and synthesized a 25-mer mimetic peptide (encompassing positions 22-46 of the ACE2 alpha-helix α1) implicated in the S1 receptor-binding domain (RBD)-ACE2 interface. The mimetic (wild-type, WT) ACE2 peptide significantly inhibited SARS-CoV-2 infection of human pulmonary Calu-3 cells in vitro. In silico protein modeling predicted that residues F28, K31, F32, F40, and Y41 of the ACE2 alpha-helix α1 are critical for the original, Delta, and Omicron strains of SARS-CoV-2 to establish the Spike RBD-ACE2 interface. Substituting these residues with alanine (A) or aspartic acid (D) abrogated the antiviral protective effect of the peptides, indicating that these positions are critical for viral entry into pulmonary cells. WT ACE2 peptide, but not the A or D mutated peptides, exhibited significant interaction with the SARS-CoV-2 S1 RBD, as shown through molecular dynamics simulations. Through identifying the critical amino acid residues of the ACE2 alpha-helix α1, which is necessary for the Spike RBD-ACE2 interface and mobilized during the in vitro viral infection of cells, we demonstrated that the WT ACE2 peptide protects susceptible K18-hACE2 mice against in vivo SARS-CoV-2 infection and is effective for the treatment of COVID-19.

The influence of sex on left ventricular remodeling in patients with aortic dissection.

AIMS: Patients with aortic dissection have a high prevalence of left ventricular structural alterations, including left ventricular hypertrophy (LVH), but little is known about the impact of sex on this regard. This study compared clinical, cardiac, and prognostic characteristics between men and women with aortic dissection. METHODS: We retrospectively assessed clinical and echocardiographic characteristics, and 1-year mortality in 367 aortic dissection patients (30% women; 66% with Stanford-A) who underwent echocardiography 60 days before or after the diagnosis of aortic dissection from three Brazilian centers. RESULTS: Men and women had similar clinical characteristics, except for higher age (59.4 ±â€Š13.4 vs. 55.9 ±â€Š11.6 years; P = 0.013) and use of antihypertensive classes (1.4 ±â€Š1.3 vs. 1.1 ±â€Š1.2; P = 0.024) and diuretics (32 vs. 19%; P = 0.004) in women compared with men. Women had a higher prevalence of LVH (78 vs. 65%; P = 0.010) and lower prevalence of normal left ventricular geometry (20 vs. 10%; P = 0.015) than men. Logistic regression analysis adjusted for confounding factors showed that women were less likely to have normal left ventricular geometry (odds ratio, 95% confidence interval = 0.42, 0.20-0.87; P = 0.019) and were more likely to have LVH (odds ratio, 95% confidence interval = 1.91, 1.11-3.27; P = 0.019). Conversely, multivariable Cox-regression analysis showed that women had a similar risk of death compared to men 1 year after aortic dissection diagnosis (hazard ratio, 95% confidence interval = 1.16, 0.77-1.75; P = 0.49). CONCLUSION: In aortic dissection patients, women were typically older, had higher use of antihypertensive medications, and exhibited a greater prevalence of LVH compared with men. However, 1-year mortality after aortic dissection diagnosis did not differ between men and women.

Production and characterization of the lipopeptide with anti-adhesion for oral biofilm on the surface of titanium for dental implants.

Titanium implants are subject to bacterial adhesion and peri-implantitis induction, and biosurfactants bring a new alternative to the fight against infections. This work aimed to produce and characterize the biosurfactant from Bacillus subtilis ATCC 19,659, its anti-adhesion and antimicrobial activity, and cell viability. Anti-adhesion studies were carried out against Streptococcus sanguinis, Staphylococcus aureus, Fusobacterium nucleatum, Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and Proteus mirabilis as the minimum inhibitory concentration and the minimum bactericidal concentration. Cell viability was measured against osteoblast and fibroblast cells. The biosurfactant was classified as lipopeptide, with critical micelle concentration at 40 µg mL- 1, and made the titanium surface less hydrophobic. The anti-adhesion effect was observed for Staphylococcus aureus and Streptococcus sanguinis with 54% growth inhibition and presented a minimum inhibitory concentration of 15.7 µg mL- 1 for Streptococcus sanguinis and Aggregatibacter actinomycetemcomitans. The lipopeptide had no cytotoxic effect and demonstrated high potential application against bacterial biofilms.

Effect of Three Semen Extenders on Sperm Quality and In Vitro Fertilization Rates of Fresh and Cryopreserved Sperm Collected from Llama (Lama glama) Vas Deferens.

The advances in Assisted Reproductive Technologies (ARTs) applied in South American camelid species are still scarce. The aim of this study was to compare the effects of three semen extenders, before and after the cryopreservation of spermatozoa obtained from the vas deferens, on sperm quality parameters and in vitro fertilization rates of llama (Lama glama) oocytes. Mature fertile llama males (Lama glama; n = 6; age: 48-60 mo.; BCS: ~2.7) were included in the study. Sperm samples were collected from each male using the surgical technique of the vas deferens deviation. Then, the sperm samples were pooled and diluted with the Tris-EY, Andromed®, or BioxCell® extender in order to subsequently carry out the sperm cryopreservation process. The sperm quality assessment related to each extender was performed before and after cryopreservation with regard to sperm morphological abnormalities, acrosome integrity, sperm viability, membrane permeability, and sperm motility traits. Moreover, in vitro fertilization (IVF) procedures were carried out to evaluate the in vitro fertility of the cryopreserved sperm samples using each extender. Overall, significant differences were observed before and after cryopreservation regarding acrosome integrity, sperm viability, membrane permeability, and sperm motility traits among the extenders used, where Tris-EY and Andromed® were better than BioxCell® (p < 0.05); however, no differences were observed regarding the sperm morphological abnormalities among extenders (p > 0.05). Moreover, multiple differences were observed with regard to the velocity and linearity kinematic parameters obtained by computerized analysis before and after the cryopreservation process, irrespective of the extender used (p < 0.05). Finally, differences were observed regarding the in vitro fertilization rates among the different extender-derived samples (p < 0.05). In conclusion, the sperm quality using Tris-EY and Andromed® was better before and after cryopreservation compared to that using BioxCell®. Although the number of fertilized oocytes obtained after the IVF process between Tris-EY and Andromed® was similar, Andromed®-derived samples showed the best sperm quality results before and after cryopreservation. This indicates that the cryopreservation extender is a determining factor in significantly improving in vitro fertilization rates when using sperm samples obtained from vas deferens in llama (Lama glama) males.

The contrasting phenotypes of neutrophils during asymptomatic versus symptomatic Leishmania braziliensis infection.

BACKGROUND: The mechanisms that mediate immune protection in individuals with subclinical (SC) or asymptomatic infection with L. braziliensis are largely unknown. Neutrophils (PMNs) have been implicated in progressive symptomatic cutaneous leishmaniasis (CL), but their potential participation in maintenance of subclinical infection is unexplored. The aim of this study was to compare the phenotypic and functional profiles of PMNs in individuals with SC infection versus patients with symptomatic CL due to L. braziliensis. METHODS: Subjects were recruited in the endemic region of Corte de Pedra, Bahia, Brazil. Surface markers to define activation status were characterized by flow cytometry. Functional responses of PMNs including phagocytic capacity, production of oxidative species, and oxidative killing of intracellular parasites were studied in vitro. RESULTS: PMNs from individuals with SC infection displayed a more activated phenotype and greater ability to control the infection than PMNs from patients with CL. In contrast, PMNs from patients with CL exhibited higher expression of HLA-DR and higher production of oxidative species than PMNs from subjects with SC infection. CONCLUSION: PMNs from individuals with SC infection can control the infection more efficiently than PMNs from patients with CL, despite the lower production of oxidants. Our observations suggest that L. braziliensis may evade microbicidal mechanisms of PMNs from patients with CL, contributing to parasite dissemination and the establishment of disease.

What Can Be Learned from the Partitioning Behavior of Proteins in Aqueous Two-Phase Systems?

This review covers the analytical applications of protein partitioning in aqueous two-phase systems (ATPSs). We review the advancements in the analytical application of protein partitioning in ATPSs that have been achieved over the last two decades. Multiple examples of different applications, such as the quality control of recombinant proteins, analysis of protein misfolding, characterization of structural changes as small as a single-point mutation, conformational changes upon binding of different ligands, detection of protein-protein interactions, and analysis of structurally different isoforms of a protein are presented. The new approach to discovering new drugs for a known target (e.g., a receptor) is described when one or more previous drugs are already available with well-characterized biological efficacy profiles.

Use of a gas-operated ventilator as a noninvasive bridging respiratory therapy in critically Ill COVID-19 patients in a middle-income country.

During the COVID-19 pandemic, there was a notable undersupply of respiratory support devices, especially in low- and middle-income countries. As a result, many hospitals turned to alternative respiratory therapies, including the use of gas-operated ventilators (GOV). The aim of this study was to describe the use of GOV as a noninvasive bridging respiratory therapy in critically ill COVID-19 patients and to compare clinical outcomes achieved with this device to conventional respiratory therapies. Retrospective cohort analysis of critically ill COVID-19 patients during the first local wave of the pandemic. The final analysis included 204 patients grouped according to the type of respiratory therapy received in the first 24 h, as follows: conventional oxygen therapy (COT), n = 28 (14%); GOV, n = 72 (35%); noninvasive ventilation (NIV), n = 49 (24%); invasive mechanical ventilation (IMV), n = 55 (27%). In 72, GOV served as noninvasive bridging respiratory therapy in 42 (58%) of these patients. In the other 30 patients (42%), 20 (28%) presented clinical improvement and were discharged; 10 (14%) died. In the COT and GOV groups, 68% and 39%, respectively, progressed to intubation (P ≤ 0.001). Clinical outcomes in the GOV and NIV groups were similar (no statistically significant differences). GOV was successfully used as a noninvasive bridging respiratory therapy in more than half of patients. Clinical outcomes in the GOV group were comparable to those of the NIV group. These findings support the use of GOV as an emergency, noninvasive bridging respiratory therapy in medical crises when alternative approaches to the standard of care may be justifiable.

Basic host response parameters to classify mortality risk in COVID-19 and community-acquired pneumonia.

Improved phenotyping in pneumonia is necessary to strengthen risk assessment. Via a feasible and multidimensional approach with basic parameters, we aimed to evaluate the effect of host response at admission on severity stratification in COVID-19 and community-acquired pneumonia (CAP). Three COVID-19 and one CAP multicenter cohorts including hospitalized patients were recruited. Three easily available variables reflecting different pathophysiologic mechanisms-immune, inflammation, and respiratory-were selected (absolute lymphocyte count [ALC], C-reactive protein [CRP] and, SpO2/FiO2). In-hospital mortality and intensive care unit (ICU) admission were analyzed as outcomes. A multivariable, penalized maximum likelihood logistic regression was performed with ALC (< 724 lymphocytes/mm3), CRP (> 60 mg/L), and, SpO2/FiO2 (< 450). A total of 1452, 1222 and 462 patients were included in the three COVID-19 and 1292 in the CAP cohort for the analysis. Mortality ranged between 4 and 32% (0 to 3 abnormal biomarkers) and 0-9% in SARS-CoV-2 pneumonia and CAP, respectively. In the first COVID-19 cohort, adjusted for age and sex, we observed an increased odds ratio for in-hospital mortality in COVID-19 with elevated biomarkers altered (OR 1.8, 3, and 6.3 with 1, 2, and 3 abnormal biomarkers, respectively). The model had an AUROC of 0.83. Comparable findings were found for ICU admission, with an AUROC of 0.76. These results were confirmed in the other COVID-19 cohorts Similar OR trends were reported in the CAP cohort; however, results were not statistically significant. Assessing the host response via accessible biomarkers is a simple and rapidly applicable approach for pneumonia.

Exploring the size of Andean condor foraging groups along an altitudinal and latitudinal gradient in the Tropical Andes: Ecological and conservation implications.

Patterns of variation in the size of vulture foraging groups, and their ecological causes and consequences, remain little explored despite strong links with the carrion recycling service that this key functional group provides. We documented the group size-frequency pattern of Andean condors Vultur gryphus gathered to feed on 42 equine carcasses experimentally placed in Bolivia, between 2012 and 2019, along an elevation range of 1,300-4,500 m asl. Based on the location (altitude and latitude) of the foraging groups, we examined the relationship between their size and species' population parameters (size and trend), habitat conditions, and livestock carcass availability and predictability. Condors utilized a high frequency (93%) of carcasses forming groups that ranged from 1 to 80 individuals (mean = 25, median = 18) and shaped a "lazy-J curve" typical pattern of size-frequency distribution whereby few groups (5, 12%) were large (> 55 individuals) and most (21, 50%) were relatively small (<19 individuals). Group size related to altitude in that most larger groups formed at lower sites (below c. 3,000 m asl), likely following an altitudinal gradient whereby larger groups are more likely to form around larger carcasses (i.e., cattle), which are more likely to occur at lower elevations. Regardless of population size, group size could be an adaptive response of condors via local enhancement for improving individual scavenging efficiency. Many information gaps on this topic still exist, thus we provide a set of questions to address them, especially amidst the unrestricted impacts of human activities that condition vulture survival globally.

Pigmented fungiform papillae of the tongue.

INTRODUCTION: Pigmented fungiform papillae of the tongue is a benign condition frequent in dark skin patients. It usually appears in the second or third decade of life, and it has been reported as autosomal dominant inheritance pattern. The diagnosis is clinical, but dermoscopy could be helpful: a classical rose petal pattern is observed. The pathogenesis is unknown, and no treatments are effective. CASE REPORT: We report a case of a 15-year-old girl with a pigmented fungiform papillae and a compatible dermatoscopy pattern. CONCLUSIONS: Knowing the existence of this entity and its characteristic dermoscopy, avoids additional invasive medical test. We have to know this entity because it is a variant of normality.

INTRODUCCIÓN: La pigmentación de las papilas fungiformes linguales es una condición benigna y relativamente frecuente en pacientes con piel oscura. Suele aparecer en la segunda o tercera décadas de la vida y se han descrito casos de herencia autosómica dominante. El diagnóstico es clínico, pero la dermatoscopia es de gran ayuda: presenta un patrón clásico en pétalos de rosa. La patogénesis se desconoce y no hay tratamientos efectivos. CASO CLÍNICO: Reportamos el caso de una niña de 15 años con pigmentación de las papilas fungiformes y con patrón dermatoscópico compatible. CONCLUSIONES: Conocer la existencia de esta afección y su característica dermatoscopia evita realizar pruebas invasivas adicionales, ya que se trata una variante de la normalidad.

The factor inhibiting HIF regulates T cell differentiation and anti-tumour efficacy.

T cells must adapt to variations in tissue microenvironments; these adaptations include the degree of oxygen availability. The hypoxia-inducible factor (HIF) transcription factors control much of this adaptation, and thus regulate many aspects of T cell activation and function. The HIFs are in turn regulated by oxygen-dependent hydroxylases: both the prolyl hydroxylases (PHDs) which interact with the VHL tumour suppressor and control HIF turnover, and the asparaginyl hydroxylase known as the Factor inhibiting HIF (FIH), which modulates HIF transcriptional activity. To determine the role of this latter factor in T cell function, we generated T cell-specific FIH knockout mice. We found that FIH regulates T cell fate and function in a HIF-dependent manner and show that the effects of FIH activity occur predominantly at physiological oxygen concentrations. T cell-specific loss of FIH boosts T cell cytotoxicity, augments T cell expansion in vivo, and improves anti-tumour immunotherapy in mice. Specifically inhibiting FIH in T cells may therefore represent a promising strategy for cancer immunotherapy.

Irritable bowel syndrome and erectile dysfunction in medical students at a Peruvian university: an analytical cross-sectional analysis.

Background: There is inconclusive evidence regarding the role of irritable bowel syndrome (IBS) in the development of erectile dysfunction (ED), especially among medical students due to high academic stress. Aim: To determine the association between IBS and ED in medical students from a Peruvian university in 2022. Methods: An analytical cross-sectional study was conducted with secondary data analysis on 133 medical students from a university in northern Peru during the 2021-II academic semester. The dependent variable was ED as measured with the 5-item International Index of Erectile Function, and the exposure variable was IBS as assessed with the Rome IV-Bristol questionnaire. Outcomes: The results were the prevalence rates of IBS and ED and the association of these variables. Results: Of the 133 medical students surveyed, the median age was 22 years (IQR, 19-24). The median score on the 5-item International Index of Erectile Function was 21 (IQR, 10-24). The prevalence of ED was 38.4% (95% CI, 30.05%-47.17%). Among the medical students 3% and 9% displayed moderate and severe ED, respectively, and 24.8%, 13.5%, and 24.1% showed moderate depressive, anxious, and severe symptoms. An overall 10.5% had IBS. Medical students with IBS had a 108% higher prevalence of ED than those without the syndrome (prevalence ratio, 2.08; 95% CI, 1.06-4.06). Other confounding variables were not significantly associated (P > .05). Clinical Implications: The results underline the importance of comprehensive sexual and mental health assessment, with an emphasis on the relationship between IBS and ED in medical students. Strengths and Limitations: Strengths include the use of validated and reliable instruments and rigorous biostatistical methods, and this is the first Peruvian investigation to explain the association between IBS and ED in medical students. Limitations include the cross-sectional design and nonprobability sampling, and there may be bias in applying the instruments. Conclusion: This study reveals a significant association between IBS and a higher prevalence of ED in these students.

Habitat type modulates sharp body mass oscillations in cyclic common vole populations.

Cyclic rodent populations exhibit pronounced changes in body mass associated with the population cycle phase, long-known as Chitty effect. Although Chitty effect is a common epiphenomenon in both America and Europe, there is still incomplete evidence about the generality of these patterns across the entire range of most species. Moreover, despite decades of research, the underlying factors driving Chitty effect remains poorly understood. Here, we examined the influence of intrinsic and extrinsic factors that may underlie observed patterns in vole size variation in the Iberian common vole Microtus arvalis asturianus. We weighed and measured 2816 adult voles that were captured during 6 trapping periods. Vole numbers and body mass showed strong period- and phase-related variation both in females and males, demonstrating marked Chitty effect in the studied population. Body mass of adult males correlated with body length, evidencing that heavier males are also structurally larger. Statistical models showed that probability of occurrence of large-sized vole (> 37 g) was significantly more likely in reproductive males, during increase and peak phases, and it was modulated by habitat, with crop fields and field margins between crops showing an increased likelihood. We suggest an effect of the habitat on vole body mass mediated by predation.

Mucoepidermoid microcarcinoma in the context of parotid gland cyst.

Mucoepidermoid carcinoma is a type of salivary gland cancer that can develop in the context of a parotid gland cyst. This type of tumor is composed of mucous, epidermoid, and intercalated cells, and usually presents as a slow-growing and painless mass. A parotid gland cyst is a condition in which a fluid-filled sac forms in the parotid gland. The tumor can be masked as it develops within the parotid cyst. A 45-year-old female patient presented with a suspect of benign neoplasm of the major salivary gland. She underwent partial right parotidectomy, which upon pathological analysis confirmed the diagnosis of mucoepidermoid microcarcinoma associated with parotid gland cysts. The patient did well and continues under regular follow-up with no further treatment.

Irritable Bowel Syndrome in medical students at a Peruvian university: a cross-sectional study.

Background: Irritable Bowel Syndrome has emerged as a significant public health challenge, particularly relevant in medical students due to the high demands of their studies, academic stress, and susceptibility to eating disorders. Nevertheless, conclusive evidence regarding the factors associated with Irritable Bowel Syndrome in the Latin American student population remains limited. The objective of this study was to determine the prevalence and factors associated with Irritable Bowel Syndrome in Human Medicine students at a university in northern Peru. Methods: A cross-sectional analytical study conducted in Lambayeque, northern Peru. With 403 Human Medicine students (66.5% female, 33.5% male). A simple random probabilistic sampling type was used, based on a list of students enrolled. A multivariate analysis was conducted to determine the factors associated using simple and multiple regression models. Generalized Linear Models were applied, using the Poisson distribution family, robust variance, and the academic year as a cluster. Results: The prevalence of Irritable Bowel Syndrome was 16.9% (95% CI: 13.37-20.86). The median age was 21 years, with 66.5% being female. In the multiple regression analysis, Irritable Bowel Syndrome was associated with a higher prevalence of depression (PR: 3.63; 95% CI: 1.26-10.49) and eating disorders (PR: 1.57; 95% CI: 1.01-2.43). For each additional year of age, the prevalence of Irritable Bowel Syndrome decreased by 9% (PR: 0.91; 95% CI: 0.83-0.99). Conclusion: This study reveals that approximately two out of every 10 students exhibit symptoms related to IBS, underscoring its significance in the Human Medicine student population. Furthermore, depression and eating disorders were identified as significant factors associated with IBS in students. Consequently, it is essential to focus efforts on early identification and the implementation of preventive measures to mitigate the development of this pathology, given its substantial prevalence in this context of Human Medicine students.

J-Integral Experimental Reduction Reveals Fracture Toughness Improvements in Thin-Ply Carbon Fiber Laminates with Aligned Carbon Nanotube Interlaminar Reinforcement.

The Mode I, Mode II, and mixed-mode interlaminar failure behavior of a thin-ply (54 gsm) carbon fiber-epoxy laminated composite reinforced by 20 µm tall z-direction-aligned carbon nanotubes (CNTs), comprising ∼50 billion CNT fibers per cm2, is analyzed following J-integral-based data reduction methods. The inclusion of aligned CNTs in the ply interfaces provides enhanced crack resistance, resulting in sustained crack deflection from the reinforced interlaminar region to the intralaminar region of the adjacent plies, i.e., the CNTs drive the crack from the interlaminar region into the plies. The CNTs do not appreciably increase the interlaminar thickness or laminate weight and preserve the intralaminar microfiber morphology. Improvements of 34 and 62% on the Mode I and Mode II initiation fracture toughness, respectively, are observed. This type of interlaminar nanoreinforcement effectively drives crack propagation from the interface to within the ply where the crack propagates parallel to the interlaminar region, providing new insight into previously reported strength and fatigue performance increases. These findings extend to industries where lightweight and durable materials are critical for improving the structural efficiency.

Polycomb protein binding and looping in the ON transcriptional state.

Polycomb group (PcG) proteins mediate epigenetic silencing of important developmental genes by modifying histones and compacting chromatin through two major protein complexes, PRC1 and PRC2. These complexes are recruited to DNA by CpG islands (CGIs) in mammals and Polycomb response elements (PREs) in Drosophila. When PcG target genes are turned OFF, PcG proteins bind to PREs or CGIs, and PREs serve as anchors that loop together and stabilize gene silencing. Here, we address which PcG proteins bind to PREs and whether PREs mediate looping when their targets are in the ON transcriptional state. While the binding of most PcG proteins decreases at PREs in the ON state, one PRC1 component, Ph, remains bound. Further, PREs can loop to each other and with presumptive enhancers in the ON state and, like CGIs, may act as tethering elements between promoters and enhancers. Overall, our data suggest that PREs are important looping elements for developmental loci in both the ON and OFF states.

Toll-like receptor-2 induced inflammation causes local bone formation and activates canonical Wnt signaling.

It is well established that inflammatory processes in the vicinity of bone often induce osteoclast formation and bone resorption. Effects of inflammatory processes on bone formation are less studied. Therefore, we investigated the effect of locally induced inflammation on bone formation. Toll-like receptor (TLR) 2 agonists LPS from Porphyromonas gingivalis and PAM2 were injected once subcutaneously above mouse calvarial bones. After five days, both agonists induced bone formation mainly at endocranial surfaces. The injection resulted in progressively increased calvarial thickness during 21 days. Excessive new bone formation was mainly observed separated from bone resorption cavities. Anti-RANKL did not affect the increase of bone formation. Inflammation caused increased bone formation rate due to increased mineralizing surfaces as assessed by dynamic histomorphometry. In areas close to new bone formation, an abundance of proliferating cells was observed as well as cells robustly stained for Runx2 and alkaline phosphatase. PAM2 increased the mRNA expression of Lrp5, Lrp6 and Wnt7b, and decreased the expression of Sost and Dkk1. In situ hybridization demonstrated decreased Sost mRNA expression in osteocytes present in old bone. An abundance of cells expressed Wnt7b in Runx2-positive osteoblasts and ß-catenin in areas with new bone formation. These data demonstrate that inflammation, not only induces osteoclastogenesis, but also locally activates canonical WNT signaling and stimulates new bone formation independent on bone resorption.