Surgical treatment of painful neuroma in amputated and non-amputated patients: does the level of neurotomy affect clinical outcomes?

PURPOSE

To compare the outcomes of distal neurotomy (DN) versus proximal neurotomy (PN) for the surgical management of painful neuromas in amputees and non-amputees, whether used in passive or active treatment.

METHODS

A retrospective study was conducted on patients who underwent surgery for painful traumatic neuromas between 2019 and 2022. DN with neuroma excision was performed at the level of the injury or amputation. PN was performed using a separate proximal approach without neuroma excision. Outcomes included a Numerical Rating Scale (NRS) score and Patient-Reported Outcomes Measurement Information System (PROMIS) scores, as well as patients' subjective assessments.

RESULTS

A total of 33 patients were included: 17 amputees and 16 non-amputees. They totalized 43 neuromas treated by DN in 21 cases and PN in 22 cases. At the median follow-up time of 13 months, there were significant decreases in all NRS and PROMIS scores in the whole series. The decrease in limb pain scores was not significantly different between groups, except for the decrease in pain interference and patient satisfaction which were higher in the DN group. Sub-group analyses found the same significant differences in amputees. Targeted muscle reinnervation (TMR) was associated with a higher decrease in PROMIS scores.

CONCLUSION

DN seemed to give better results in amputees but there were confusing factors related to associated lesions. In other situations, the non-inferiority of PN was demonstrated. PN could be of interest for treating neuromas of superficial sensory nerves, for avoiding direct revision of a well-fitted stump and in conjunction with TMR.

T Cells Expressing a Modified FcγRI Exert Antibody-Dependent Cytotoxicity and Overcome the Limitations of CAR T-cell Therapy against Solid Tumors

The pioneering design of chimeric antigen receptor (CAR) T-cell therapy demonstrated the potential of reprogramming the immune system. Nonetheless, T-cell exhaustion, toxicity, and suppressive microenvironments limit their efficacy in solid tumors. We previously characterized a subset of tumor-infiltrating CD4+ T cells expressing the FcγRI receptor. Herein, we detail engineering of a receptor, based on the FcγRI structure, allowing T cells to target tumor cells using antibody intermediates. These T cells showed effective and specific cytotoxicity only when an appropriate antibody was added. Only target-bound antibodies activated these cells, while free antibodies were internalized without activation. Their cytotoxic activity was correlated to target protein density, therefore targeting tumor cells with high antigen density while sparing normal cells with low or no expression. This activation mechanism prevented premature exhaustion. Furthermore, during antibody-dependent cytotoxicity these cells secreted attenuated cytokine levels compared with CAR T cells, thereby enhancing their safety profile. These cells eradicated established melanomas, infiltrated the tumor microenvironment, and facilitated host immune cell recruitment in immunocompetent mice. In NOD/SCID gamma mice the cells infiltrate, persist, and eradicate tumors. As opposed to CAR T-cell therapies, which require changing the receptor across different types of cancer, our engineered T cells remain the same across tumor types, while only the injected antibody changes. Overall, we generated a highly flexible T-cell therapy capable of binding a wide range of tumor cells with high affinity, while preserving the cytotoxic specificity only to cells expressing high density of tumor-associated antigens and using a single manufacturing process.

Does the choice of the optic portal influence the radiographic and early functional results in acute acromioclavicular disjunctions?

Exposure of the coracoid process during arthroscopic stabilization of acute acromioclavicular disjunctions (ACDs) can be achieved either by passing an extra- articular optical portal through the subacromial space or by an intra-articular optical route through the glenohumeral joint with opening of the rotator interval. The objective of our study was to compare the impact on the functional results of these two optical routes. This was a retrospective, multicentre study that included patients operated on for an acute acromioclavicular disjunction arthroscopically. The treatment consisted of surgical stabilization under arthroscopy. The surgical indication was retained for an acromioclavicular disjunction of grade 3, 4 or 5, according to the Rockwood classification. Group 1, which consisted of 10 patients, was operated on with an extra-articular subacromial optical route, and group 2, which consisted of 12 patients, was operated on with an intra-articular optical route with opening of the rotator interval according to the habits of the surgeon. A follow-up of 3 months was performed. The functional results were evaluated for each patient using the Constant score, Quick DASH, and SSV. The delays in returning to professional and sports activities were also noted. A precise postoperative radiological analysis made it possible to analyse the quality of the radiological reduction. No significant difference between the two groups was found between the Constant score (88 vs. 90; p = 0.56), Quick DASH (7 vs. 7; p = 0.58), or SSV (88 vs. 93; p = 0.36). The times to return to work (6.8 weeks vs. 7.0 weeks; p = 0.54) and sports activities (15.6 weeks vs. 19.5 weeks; p = 0.53) were also comparable. The quality of the radiological reduction was satisfactory in the two groups and did not depend on the approach. No clinically or radiologically significant differences between the extra-articular and intra-articular optical portals in the surgical treatment of acute ACDs were found. The optical route can be chosen according to the habits of the surgeon.

Tumours involving the neural foramina in children: beyond neuroblastoma

AIM

To characterise tumours that involve the neural foramina in children, including prevalence, demographics, and imaging features.

MATERIAL AND METHODS

This retrospective single-centre study comprised 36 boys and 34 girls who presented with spinal or paraspinal lesions involving the neural foramina. Two certified radiologists reviewed the imaging features, including the level of spinal involvement, the number of involved foramina, foraminal widening, tumour epicentre, and cord compression. Medical charts were reviewed for patients' demographics and tumour pathology. Tumours were classified as benign or malignant, and neuroblastomas were further classified as low or intermediate risk versus high risk.

RESULTS

Thirty-three (47%) of the patients had neuroblastic tumours. Fourteen (20%) of the patients had sarcomas (mainly Ewing sarcoma). Other less common aetiologies included neurofibromas, germ cell tumours, Langerhans cell histiocytosis and haemangiomas. Neuroblastic tumours were particularly common in the thoraco-lumbar region, and considerably less prevalent in the sacral and cervical regions. Additional features, such as foraminal widening, the number of foramina involved, and cord compression, did not help discriminate between neuroblastic and non-neuroblastic tumours. Most tumours (80%) were malignant. Most benign tumours (>50%) were associated with a genetic predisposition syndrome.

CONCLUSION

In evaluating neoplasms that involve the neural foramina in children, neuroblastic tumours are most common. Nevertheless, other aetiologies should be considered, mainly sarcomas. Most lesions in children are malignant. When encountering a benign mass, genetic counselling should be considered.

Classification of node-positive melanomas into prognostic subgroups using keratin, immune, and melanogenesis expression patterns

Cutaneous melanoma tumors are heterogeneous and show diverse responses to treatment. Identification of robust molecular biomarkers for classifying melanoma tumors into clinically distinct and homogenous subtypes is crucial for improving the diagnosis and treatment of the disease. In this study, we present a classification of melanoma tumors into four subtypes with different survival profiles based on three distinct gene expression signatures: keratin, immune, and melanogenesis. The melanogenesis expression pattern includes several genes that are characteristic of the melanosome organelle and correlates with worse survival, suggesting the involvement of melanosomes in melanoma aggression. We experimentally validated the secretion of melanosomes into surrounding tissues by melanoma tumors, which potentially affects the lethality of metastasis. We propose a simple molecular decision tree classifier for predicting a tumor's subtype based on representative genes from the three identified signatures. Key predictor genes were experimentally validated on melanoma samples taken from patients with varying survival outcomes. Our three-pattern approach for classifying melanoma tumors can contribute to advancing the understanding of melanoma variability and promote accurate diagnosis, prognostication, and treatment.

Bisphenol S Impaired Human Granulosa Cell Steroidogenesis in Vitro

Bisphenol S (BPS) is a structural analog of the endocrine disruptor bisphenol A (BPA); it is the main BPA replacement in the plastics industry. Previous studies have shown that BPA and BPS exhibit similar effects on reproduction in fish and rodent species. BPS reportedly alters steroidogenesis in bovine granulosa cells. Luteinised granulosa cells collected from 59 women who were undergoing an in vitro fertilization procedure were cultured for 48 h in the presence or absence of BPS (10 nM, 100 nM, 1 µM, 10 µM or 50 µM). BPS exposure was investigated by assessing follicular fluids from these 59 women for their BPS content. Culture medium, cells, total messenger RNA (mRNA) and total protein extracted from the luteinised granulosa cells were examined for oestradiol and progesterone secretion, cellular proliferation, viability, gene expression, steroidogenic enzyme expression and cell signaling. BPS was measured in follicular fluids using mass spectrometry. Exposure of granulosa cells to 10 or 50 µM BPS for 48 h induced a 16% (p = 0.0059) and 64% (p < 0.0001) decrease, respectively, in progesterone secretion; 50 µM BPS decreased oestradiol secretion by 46% (p < 0.0001). Ten µM BPS also tended to reduce CYP11A1 protein expression by 37% (p = 0.0947) without affecting HSD3B1 and CYP19A1 expression. Fifty µM BPS increased ERRγ expression. Environmental levels of BPS (nanomolar range) did not induce changes in steroidogenesis in human granulosa cells. The effects of BPS were observed after only 48 h of BPS exposure. These acute effects might be similar to chronic effects of physiological BPS levels.

Microvascular anastomosis using loupes and smartphone magnification: Experimental study for application to limited-resource environments

Finger revascularization has been performed without a microscope in limited-resource environments only when absolutely necessary. This experimental study sought to assess the feasibility of microvascular anastomosis in rats performed using loupes or smartphone magnification. Thirty rats were divided into three groups of 10 individuals according to the magnification method used: operating microscope (control group M), surgical loupes (group L) and smartphone (group S). The infrarenal aorta was dissected under a microscope, then anastomosed by interrupted sutures using the group-specific magnifying device. The main analytical criteria were vessel diameter, anastomosis duration, immediate flow patency (T0), patency after one hour (T1) and anastomosis quality. Anastomosis duration was comparable between groups M and L, but was twice as long in group S. The number of leaks at clamp removal was higher in group S. Patency rates at T0 and T1 were 100% in groups M and L, but were significantly lower in group S. The anastomosis quality was low in group L and poor in group S. Anastomosis of digital arteries using loupes is possible, but the resulting quality is lower than with a microscope. Current smartphones are not adequate for performslt ing microvascular repairs in a living model.

The state of microsurgical practice in French forward surgical facilities from 2003 to 2015

Microsurgery is an unusual procedure in the theatres of military operations. We sought to analyze the state of microsurgical practices in the French medical treatment facilities (MTFs) deployed around the world in the 21st century. A retrospective study was conducted among all patients who were operated on in French forward surgical facilities between 2003 and 2015. Those who underwent microsurgical procedures for nerve injury, vascular injury, or extremity reconstruction were included. Only early vascular results were assessed. Among the 2589 patients operated on for an extremity injury during the study period, 56 (2.1%) were included, with the group composed of 29 patients with isolated nerve injuries, 28 patients with nerve and arterial injuries, and two patients with isolated arterial injuries, mostly at the hand level. Nerve procedures predominantly consisted of direct suturing, although autografting and nerve transfers were also performed. Thirteen microvascular repairs were carried out, including nine cases of proximal or digital revascularization; revascularization was successful in six of the nine cases. These procedures were completed by orthopedic surgeons trained in microsurgery, mostly under loupes magnification. Routine nerve repair in the field seems to be specific to French MTFs. Salvage of amputated or devascularized fingers in the combat zone had never been reported before. Such emphasizes the need to train deployed orthopedic surgeons to perform microsurgical procedures and to equip all MTFs with basic microsurgical sets and magnification means.

Adipocytes sensitize melanoma cells to environmental TGF-β cues by repressing the expression of miR-211

Transforming growth factor-β (TGF-β) superfamily members are critical signals in tissue homeostasis and pathogenesis. Melanoma grows in the epidermis and invades the dermis before metastasizing. This disease progression is accompanied by increased sensitivity to microenvironmental TGF-β. Here, we found that skin fat cells (adipocytes) promoted metastatic initiation by sensitizing melanoma cells to TGF-β. Analysis of melanoma clinical samples revealed that adipocytes, usually located in the deeper hypodermis layer, were present in the upper dermis layer within proximity to in situ melanoma cells, an observation that correlated with disease aggressiveness. In a coculture system, adipocytes secreted the cytokines IL-6 and TNF-α, which induced a proliferative-to-invasive phenotypic switch in melanoma cells by repressing the expression of the microRNA miR-211. In a xenograft model, miR-211 exhibited a dual role in melanoma progression, promoting cell proliferation while inhibiting metastatic spread. Bioinformatics and molecular analyses indicated that miR-211 directly targeted and repressed the translation of TGFBR1 mRNA, which encodes the type I TGF-β receptor. Hence, through this axis of cytokine-mediated repression of miR-211, adipocytes increased the abundance of the TGF-β receptor in melanoma cells, thereby enhancing cellular responsiveness to TGF-β ligands. The induction of TGF-β signaling, in turn, resulted in a proliferative-to-invasive phenotypic switch in cultured melanoma cells. Pharmacological inhibition of TGF-β prevented these effects. Our findings further reveal a molecular link between fat cells and metastatic progression in melanoma that might be therapeutically targeted in patients.

Robot-Assisted Laparoscopic Fundoplications in Pediatric Surgery: Experience Review

INTRODUCTION

 Laparoscopic fundoplicature for gastroesophageal reflux disease has become the gold standard because of the improvement of postoperative rehabilitation compared with the open procedure. The robot-assisted surgery has brought new advantages for the patient and the surgeon compared with laparoscopy. We studied this new approach and the learning curve.

MATERIALS AND METHODS

 Sixty robot-assisted fundoplicatures were performed in two university pediatric surgery centers. Data of the patients were recorded, including peroperative data (operation length and complications), postoperative recoveries, and clinical evolution. The learning curve was evaluated retrospectively and each variable was compared along this learning curve.

RESULTS

 We observed a flattening of the learning curve after the 20th case for one surgeon. The mean operative time decreased significantly to 80 ± 10 minutes after 20 cases. There were no conversions to an open procedure. A revision surgery was indicated for 4.7% of the patients by a surgical robot-assisted laparoscopic approach.

CONCLUSION

 The robotic system appears to add many advantages for surgical ergonomic procedures. There is a potential benefit in operating time with a short technical apprenticeship period. The setting up system is easy with a short docking time.

Metacarpal bone reconstruction by a cementless induced membrane technique

Gunshot wounds to the hand often produce complex injuries and large segmental bone defects. Bone reconstruction remains a challenge in this context. The induced membrane technique is a simple and effective procedure for reconstruction of segmental bone defects. The technique is straightforward but must be performed rigorously. Usually polymethylmethacrylate (PMMA) cement is required for the first stage of the surgery. We describe four cases of metacarpal bone reconstruction after gunshot wounds in a limited-resource setting. Two patients were treated using the induced membrane technique with a polypropylene syringe body instead of PMMA cement, which was unavailable in this situation. A thick membrane was observed 6 weeks after spacer implantation. Bone union was achieved in all cases.

Laparoscopic one port appendectomy: Evaluation in pediatric surgery

BACKGROUND

Appendectomy is a well-established surgical procedure in pediatric surgery used in the management of acute appendicitis. With the continuous advancement in the field of minimal invasive surgery, the recent focus is on single incision laparoscopic (SIL) surgery. SILA also goes further in order to decrease pain, improve recovery and enhance patient satisfaction. However, this approach is still not a well-established technique and not widely practiced, especially in pediatric surgery.

METHODS

We prospectively recorded the data in our pediatric universitary hospital center since January, 01 2017 to July, 01 2017. Patients included in this study were randomized in two groups: SILA group (managed by one-port laparoscopy, n=40) and LA group (conventional laparoscopy using three trocars, n=40).

RESULTS

The mean operative time for SILA was significantly lower. There were no postoperative complications in SILA group. If peritonitis was associated with appendicitis, the operative duration was not significantly different between each group. The duration in recovery room after surgery was significantly lower in SILA group. The morphine consumption was significantly lower for SILA group according to patient weight. SILA is less painful significantly than CLA for the first postoperative 6 h. After, even if SILA appears less painful, difference is not significant. The hospital length of stay was significantly higher in LA than SILA group CONCLUSIONS: SILA procedure for appendectomy appears to be safe and efficient for appendicitis management in children. This technique could be applied in routine as in emergency tome.

TYPE OF STUDY

Prospective comparative study LEVEL OF EVIDENCE: II.

Guidelines for reporting secondary findings of genome sequencing in cancer genes: the SFMPP recommendations

In oncology, the expanding use of multi-gene panels to explore familial cancer predisposition and tumor genome analysis has led to increased secondary findings discoveries (SFs) and has given rise to important medical, ethical, and legal issues. The American College of Medical Genetics and Genomics published a policy statement for managing SFs for a list of genes, including 25 cancer-related genes. Currently, there are few recommendations in Europe. From June 2016 to May 2017, the French Society of Predictive and Personalized Medicine (SFMPP) established a working group of 47 experts to elaborate guidelines for managing information given on the SFs for genes related to cancers. A subgroup of ethicists, lawyers, patients' representatives, and psychologists provided ethical reflection, information guidelines, and materials (written consent form and video). A subgroup with medical expertise, including oncologists and clinical and molecular geneticists, provided independent evaluation and classification of 60 genes. The main criteria were the "actionability" of the genes (available screening or prevention strategies), the risk evaluation (severity, penetrance, and age of disease onset), and the level of evidence from published data. Genes were divided into three classes: for class 1 genes (n = 36), delivering the information on SFs was recommended; for class 2 genes (n = 5), delivering the information remained questionable because of insufficient data from the literature and/or level of evidence; and for class 3 genes (n = 19), delivering the information on SFs was not recommended. These guidelines for managing SFs for cancer-predisposing genes provide new insights for clinicians and laboratories to standardize clinical practices.

Periodontal innate immune mechanisms relevant to atherosclerosis

Atherosclerosis is a common cardiovascular disease in the USA where it is a leading cause of illness and death. Atherosclerosis is the most common cause for heart attack and stroke. Most commonly, people develop atherosclerosis as a result of diabetes, genetic risk factors, high blood pressure, a high-fat diet, obesity, high blood cholesterol levels, and smoking. However, a sizable number of patients suffering from atherosclerosis do not harbor the classical risk factors. Ongoing infections have been suggested to play a role in this process. Periodontal disease is perhaps the most common chronic infection in adults with a wide range of clinical variability and severity. Research in the past decade has shed substantial light on both the initiating infectious agents and host immunological responses in periodontal disease. Up to 46% of the general population harbors the microorganism(s) associated with periodontal disease, although many are able to limit the progression of periodontal disease or even clear the organism(s) if infected. In the last decade, several epidemiological studies have found an association between periodontal infection and atherosclerosis. This review focuses on exploring the molecular consequences of infection by pathogens that exacerbate atherosclerosis, with the focus on infections by the periodontal bacterium Porphyromonas gingivalis as a running example.

Massive postoperative pulmonary embolism in a young woman using oral contraceptives: the value of a preoperative anesthetic consult

We describe the case of a woman with a history of active tabagism and on the oral contraceptive Yasmin, presenting in the Post-Anesthesia Care Unit (PACU) with a cardiac arrest due to massive pulmonary embolism following transforaminal lumbar interbody fusion surgery. The patient had preoperatively several risk factors for deep venous thrombosis. This case-report emphasizes the value of a preoperative anesthetic visit and eventual temporary cessation of certain oral contraceptives in specific cases.

Periodontal innate immune mechanisms relevant to obesity

Obesity affects over 35% of the adult population of the USA, and obesity-related illnesses have emerged as the leading cause of preventable death worldwide, according to the World Health Organization. Obesity's secondary morbidities include increased risk of cardiovascular disease, type II diabetes, and cancer, in addition to increased occurrence and severity of infections. Sedentary lifestyle and weight gain caused by consumption of a high-fat diet contribute to the development of obesity, with individuals having a body mass index (BMI) score > 30 being considered obese. Genetic models of obesity (ob/ob mice, db/db mice, and fa/fa rats) have been insufficient to study human obesity because of the overall lack of genetic causes for obesity in human populations. To date, the diet-induced obese (DIO) mouse model best serves research studies relevant to human health. Periodontal disease presents with a wide range of clinical variability and severity. Research in the past decade has shed substantial light on both the initiating infectious agents and host immunological responses in periodontal disease. Up to 46% of the general population harbors the microorganism(s) associated with periodontal disease, although many are able to limit the progression of periodontal disease or even clear the organism(s) if infected. In the last decade, several epidemiological studies have found an association between obesity and increased incidence of periodontal disease. This review focuses on exploring the immunological consequences of obesity that exacerbate effects of infection by pathogens, with focus on infection by the periodontal bacterium Porphyromonas gingivalis as a running example.

p53 is an important regulator of CCL2 gene expression

The p53 protein is a sequence-specific DNA-binding factor that regulates inflammatory genes such as CCL2/MCP-1 that may play a role in various diseases. A recent study has indicated that the knockdown of human p53 leads to a strong negative regulation of CCL2 induction. We are therefore interested in how p53 regulates CCL2 gene expression. In the following study, our findings indicate that UV-induced p53 accumulation in mouse macrophages significantly decreases LPS-induced CCL2 production, and that p53 binds to CCL2 5'UTR in the region (16-35). We also found that a p53 domain (p53pep170) mimics full length p53 to down-regulate CCL2 promoter activity. Treatment of p53-deficient mouse primary macrophages with synthetic p53pep170 was found to decrease LPS-induced production of CCL2 without association with cellular endogenous p53. CCL2 production induced by lentiCLG in human monocytes or mouse primary macrophages was blocked in the presence of p53pep170. Overall, these results demonstrate that p53 or its derived peptide (p53pep170) is an important regulator of CCL2 gene expression via its binding activity, and acts as a novel model for future studies linking p53 and its short peptide to pave the way to possible pharmaceutical intervention of CCL2-mediated inflammatory and cancer diseases.

p53 peptide prevents LITAF-induced TNF-alpha-mediated mouse lung lesions and endotoxic shock

Abnormal and prolonged inflammatory reaction is seen in a wide variety of disorders, and high level of Tumor Necrosis Factor alpha (TNF-α) has been linked to these disorders. Therefore, modulation of TNF-α expression is important in the regulation of inflammatory disorders. In our previous study, we have shown that a transcription factor LPS-induced TNF factor (LITAF) significantly induces TNF-α production. Furthermore, we found that p53 and its synthetic peptide 162-motif specifically downregulate LITAF/TNF-α gene expression in human cells in vitro. Thus, in the present study, the role of p53 in regulating TNF-α-mediated inflammation was investigated. Our data showed that a synthetic peptide, named 162-motif, corresponding to this region functions independently from p53 to cause a significant suppression of TNF-α gene expression in mouse primary macrophages. The 162-motif, when delivered into cells and organs, reduces serum TNF-α level in mice and prevents TNF-α-induced lung lesions and endotoxic shock. Our findings highlight the regulation of LITAF/TNF-α by p53 and its short peptide 162-motif. These in vitro and in vivo observations serve to pave the way for pharmacotherapeutic approaches in the treatment of inflammatory diseases.

LITAF and TNFSF15, two downstream targets of AMPK, exert inhibitory effects on tumor growth

Lipopolysaccharide (LPS)-induced tumor necrosis factor (TNF) α factor (LITAF) is a multiple functional molecule whose sequence is identical to the small integral membrane protein of the lysosome/late endosome. LITAF was initially identified as a transcription factor that activates transcription of proinflammatory cytokine in macrophages in response to LPS. Mutations of the LITAF gene are associated with a genetic disease, called Charcot-Marie-Tooth syndrome. Recently, we have reported that mRNA levels of LITAF and TNF superfamily member 15 (TNFSF15) are upregulated by 5' adenosine monophosphate (AMP)-activated protein kinase (AMPK). The present study further assesses their biological functions. Thus, we show that 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR), a pharmacological activator of AMPK, increases the abundance of LITAF and TNFSF15 in LNCaP and C4-2 prostate cancer cells, which is abrogated by small hairpin RNA (shRNA) or the dominant-negative mutant of AMPK α1 subunit. Our data further demonstrate that AMPK activation upregulates the transcription of LITAF. Intriguingly, silencing LITAF by shRNA enhances proliferation, anchorage-independent growth of these cancer cells and tumor growth in the xenograft model. In addition, our study reveals that LITAF mediates the effect of AMPK by binding to a specific sequence in the promoter region. Furthermore, we show that TNFSF15 remarkably inhibits the growth of prostate cancer cells and bovine aortic endothelial cells in vitro, with a more potent effect toward the latter. In conjuncture, intratumoral injection of TNFSF15 significantly reduces the size of tumors and number of blood vessels and induces changes that are characteristic of tumor cell differentiation. Therefore, our studies for the first time establish the regulatory axis of AMPK-LITAF-TNFSF15 and also suggest that LITAF may function as a tumor suppressor.

An application of monotone functions decomposition to the reconstruction of gene regulatory networks

We describe the reconstruction of a gene regulatory network involved with the Toll-like Receptor signaling pathways. By applying our recent identification algorithm to a time series gene expression dataset, we identify regulatory interactions between genes and construct discrete-time piece-wise affine regulatory functions. Our validation shows that our model predicts the expression levels of the genes involved in the network with good accuracy.

Moesin-induced signaling in response to lipopolysaccharide in macrophages

BACKGROUND AND OBJECTIVE

Many physiological and pathophysiological conditions are attributable in part to cytoskeletal regulation of cellular responses to signals. Moesin (membrane-organizing extension spike protein), an ERM (ezrin, radixin and moesin) family member, is involved in lipopolysaccharide (LPS)-mediated events in mononuclear phagocytes; however, its role in signaling is not fully understood. The aim of this study was to investigate the LPS-induced moesin signaling pathways in macrophages.

MATERIAL AND METHODS

Macrophages were stimulated with 500 ng/mL LPS in macrophage serum-free medium. For blocking experiments, cells were pre-incubated with anti-moesin antibody. Moesin total protein and phosphorylation were studied with western blotting. Moesin mRNA was assessed using quantitative real-time PCR. To explore binding of moesin to LPS, native polyacrylamide gel electrophoresis (PAGE) gel shift assay was performed. Moesin immunoprecipitation with CD14, MD-2 and Toll-like receptor 4 (TLR4) and co-immunoprecipitation of MyD88-interleukin-1 receptor-associated kinase (IRAK) and IRAK-tumor necrosis factor receptor-activated factor 6 (TRAF6) were analyzed. Phosphorylation of IRAK and activities of MAPK, nuclear factor kappaB (NF-kappaB) and IkappaBalpha were studied. Tumor necrosis factor alpha, interleukin-1beta and interferon beta were measured by ELISA.

RESULTS

Moesin was identified as part of a protein cluster that facilitates LPS recognition and results in the expression of proinflammatory cytokines. Lipopolysaccharide stimulates moesin expression and phosphorylation by binding directly to the moesin carboxyl-terminus. Moesin is temporally associated with TLR4 and MD-2 after LPS stimulation, while CD14 is continuously bound to moesin. Lipopolysaccharide-induced signaling is transferred downstream to p38, p44/42 MAPK and NF-kappaB activation. Blockage of moesin function interrupts the LPS response through an inhibition of MyD88, IRAK and TRAF6, negatively affecting subsequent activation of the MAP kinases (p38 and ERK), NF-kappaB activation and translocation to the nucleus.

CONCLUSION

These results suggest an important role for moesin in the innate immune response and TLR4-mediated pattern recognition in periodontal disease.

Inhibition of SFRP1 reduces severity of periodontitis

Porphyromonas gingivalis (P. gingivalis) is implicated as a major pathogen in periodontitis, a common infectious disease characterized by the inflammation and destruction of periodontal tissues. Secreted frizzled-related protein 1 (SFRP1) modulates apoptosis in different cell types. To characterize the roles of SFRP1 in periodontitis, we used a P. gingivalis-induced murine periodontitis model. Inflammatory responses were measured by morphometric and histomorphometric analysis, apoptosis assay, and immunohistochemistry. We found that P. gingivalis-infected mouse periodontal tissues expressed significantly more SFRP1 compared with those of control mice. Also, in P. gingivalis-infected animals, more apoptosis of inflammatory cells, fibroblasts, and bone-lining cells was observed compared with controls. Antibody experiments aimed at inhibiting SFRP1 expression in periodontitis resulted in a reduction of periodontal breakdown, inflammatory cell infiltrate, osteoclastogenesis, and apoptosis of inflammatory cells and fibroblasts. The results of our studies suggest that SFRP1 may be involved in the development of periodontitis, since inhibiting SFRP1 resulted in reduced periodontal breakdown.

Role of secreted frizzled-related protein 1 (SFRP1) in wound healing

Wound healing is a complex cascade of events, which diminishes the size of the wound and reestablishes tissue integrity. Secreted frizzled-related protein 1 (SFRP1) contributes to the inhibition of apoptosis in fibroblast populations. We investigated the role of SFRP1 in a mouse wound-healing model; 2.0-mm excisional wounds were created in the scalp and hard palate. Healing responses were measured by histomorphometric analysis, apoptosis assay, and immunohistochemistry. Dermal wounds did not harbor SFRP1, but healed faster than palatal wounds which expressed significant levels of SFRP1. Antibody experiments aimed at blocking SFRP1 in palatal wounds resulted in promotion of wound closure, enhancement of new tissue formation, decrease of inflammatory cell infiltrate, and increase of apoptotic fibroblasts. Analysis of the present data suggests that SFRP1 may be partly responsible for the poorer healing performance of the palatal wounds compared with dermal wounds. Blocking SFRP1 results in improvement of palatal healing outcomes.

Genetic correlational analysis of glycogen synthase kinase-3 beta and prepulse inhibition in inbred mice

In humans, GSK-3 beta activity is diminished in schizophrenic patients as is prepulse inhibition of the startle response (PPI). We performed a genetic correlational analysis between published PPI values and frontal cortex GSK-3 activity analyzed in our laboratory in 10 inbred mouse strains. This methodology could indicate relevant parameters for study in an animal model. Indeed, we obtained significant correlations between the enzyme's activity and PPI measured by two different methods. This may indicate that investigation of the genetics of GSK-3 beta regulation holds promise for understanding some of the biochemical underpinnings of schizophrenia.

IGF-1 signaling enhances cell survival in periodontal ligament fibroblasts vs. gingival fibroblasts

The role of insulin-like growth factors (IGFs) in the regulation of apoptosis has been suggested, yet their impact on specific cells such as periodontal ligament fibroblasts (PDLF) and gingival fibroblasts (GF) remains unknown. The purpose of this study was to test the role of IGF-1 signaling in cell survival in PDLF compared with GF. In periodontal tissue sections, a significantly reduced apoptotic rate was first demonstrated in PDLF compared with GF. In vitro, IGF-1 substantially enhanced cell survival in PDLF compared with GF by the up-regulation of anti-apoptotic molecules and the down-regulation of pro-apoptotic molecules. Furthermore, the differential expression of insulin-like growth factor binding protein 5 (IGFBP-5) was observed in vitro, and its differential distribution was confirmed in vivo. Analysis of the present data suggests an enhanced cell survival in PDLF compared with GF by the up-regulation of IGF-1 signaling pathway.

Identification of genes differentially expressed in cultured human osteoblasts versus human fibroblasts by DNA microarray analysis

Little is known about patterns of gene expression from cells populating the connective tissues. This study investigated the possible variance of gene expression profile between human osteoblasts (HO) and human fibroblasts (HF) in vitro, using DNA microarray technology. Clustering identification was used to compare expression patterns between HO and HF for biological significance. Our results showed that genes encoding the extracellular matrix or apoptosis-related proteins tended to be expressed in greater abundance in HO, while more proteolysis-related proteins were expressed in higher level in HF. Significant differences in expression were also noted with genes related to signaling pathways. To confirm the array results, three genes (periostin, MFG-E8, MMP-10) were selected and analyzed independently by RT-PCR and northern blot. The results were found consistent with the array data in HO and HF. The present findings suggest that HO and HF differ not only phenotypically but in the expression level of tissue specific genes to assure the turnover and homeostasis of their respective tissues.

Identification of genes differentially expressed in cultured human periodontal ligament fibroblasts vs. human gingival fibroblasts by DNA microarray analysis

Despite their similar spindle-shaped appearance, periodontal ligament fibroblasts (PDLF) and gingival fibroblasts (GF) appear to display distinct functional activities in the maintenance of tissue integrity and during inflammatory/immune responses. We postulated that different characteristics of PDLF and GF are defined by the differential expression of specific genes. To test this, we investigated the possible variance of gene expression profile between cultured PDLF and GF, using DNA microarray technology. One hundred sixty-three genes were found differentially expressed by at least three-fold between PDLF and GF. Genes encoding transmembrane proteins and cytoskeleton-related proteins tended to be up-regulated in PDLF, whereas genes encoding cell-cycle regulation proteins and metabolism-related proteins tended to be up-regulated in GF. We concluded that PDLF and GF appear to display different gene expression patterns that may reflect intrinsic functional differences of the two cell populations and may well coordinate with their tissue-specific activities.

Moesin: a potential LPS receptor on human monocytes

Bacterial endotoxin (lipopolysaccharide, LPS), a glycolipid found in the outer membrane of Gram-negative bacteria, induces the secretion of pro-inflammatory cytokines such as tumor necrosis factor alpha (TNF-alpha ), interleukin (IL)-1, and IL-6 by monocytes/macrophages. The secretion of these biologically active compounds leads to multiple pathological conditions, such as septic shock. There is substantial evidence that chronic exposure to LPS in periodontal diseases mediates, at least in part, the tissue destruction associated with the Gram-negative infection. LPS receptor has been shown to be CD14, a 55 kDa protein. LPS-CD14 interactions mediate many monocyte/macrophage functions in the inflammatory response. However, CD14 lacks a cytoplasmic domain, or any known signal transduction sequence motif, suggesting the existence of another cell surface domain capable of transducing signals. More recently, significant work has implicated Toll proteins in LPS-mediated signaling. The purpose of the present work was to investigate, identify, and characterize secondary LPS binding cell surface domain(s) on monocytes/macrophages. Initial experiments with anti-CD14 blocking antibody revealed only partial blocking of the LPS induced TNF-alpha response. The kinetics of these experiments suggested a second, low-affinity receptor. Cross-linking experiments were performed to identify LPS binding sites. Two domains were identified: a 55 kDa protein which was inhibited by anti-CD14 (presumably the CD14 receptor) and a second 78 kDa domain. Partial protein sequencing of the 78 kDa domain using mass spectroscopic analysis ascribed this domain to Moesin (membrane organizing extension spike protein). Preliminary experiments using anti-Moesin monoclonal antibody revealed a dose-dependent blocking of LPS induced TNF-alpha response with a total blocking at 50 microg/ml. Irrelevant isotype controls had no effect. Additional experiments were performed to evaluate the specificity of the anti-Moesin blocking. Separate experiments evaluated anti-Moesin effects on monocyte chemotaxis, IL-1 production in response to IL-1 stimulation, and TNF-alpha secretion in response to Staphylococcus aureus stimulation. Anti-Moesin antibody only blocked LPS-mediated events. Histological analysis of tissue sections harvested from LPS-induced skin lesions exhibited a 3-fold reduction of the polymorphonuclear neutrophil infiltrate in Moesin-deficient mice compared to wild type mice. The data suggest that Moesin functions as an independent LPS receptor on human monocytes.

IL-1 plays a critical role in oral, but not dermal, wound healing

Wound healing is a well-orchestrated complex process leading to the repair of injured tissues. After injury, proinflammatory cytokines act as important modulators of the inflammatory process. IL-1 expression has been regarded as necessary for healing; however, its effects have also been implicated in delayed wound repair. Currently, there is no consensus or direct evidence that IL-1 activity plays a central role in the healing process. The present investigation was undertaken to define the role of IL-1R signaling in the healing outcome of an excisional wound in the palate or scalp of mice that had targeted deletions of the IL-1R type 1 (IL-1R1(-/-)) compared with matched wild-type mice. Histomorphometric analysis was undertaken to assess the degree of healing and the recruitment of polymorphonuclear and mononuclear phagocytes. After 14 days, wild-type mice exhibited complete closure of intraoral wounds, while IL-1R1(-/-) animals had only partial closure (50%). In the IL-1R1(-/-) mice, healing tissues exhibited a persistent inflammatory cell infiltrate, which did not occur in wild-type animals. Treatment with antibiotics significantly diminished the persistent inflammatory infiltrate and improved healing in the experimental animals. In contrast to oral wounds, the rate of healing and recruitment of polymorphonuclear cells in scalp wounds was similar in IL-1R1(-/-) and wild-type mice. The present data underscore the importance of IL-1 in wound healing in a challenging environment and identify its principal role in facilitating the healing process by protecting an open wound from bacterial insult. In a less challenging environment, the production of new connective tissue and its coverage by migrating epithelium are minimally affected by the absence of IL-1 activity.

[The efficacy of a doctor-patient appointment in a primary care setting dedicated to preventive medicine]

BACKGROUND

Previous data on the importance of promoting cessation of smoking, physical activity and a healthy diet exists in the literature. However, there is insufficient evidence that counseling healthy patients to change their life-styles will indeed have a positive effect on their behavior. In this study we examined whether a single doctor-patient appointment dedicated to preventive medicine can have a positive effect on cessation of smoking, promoting physical activity and weight control.

METHOD

Eighty-eight patients from the "French Carmel" Clinic, aged 25-50, were summoned to a doctor-patient appointment lasting 20 minutes. The patients filled out a questionnaire and their weight and height were measured. The doctor counseled the patients to cease smoking, increase their physical activity and lose weight. The counseling was patient-oriented. Six to twelve months later the patients were interviewed by telephone and data was collected. The data was processed on a windows-based SPSS program.

RESULTS

Of the 25 smoking patients, 2 (8%) stopped smoking, another 5 (20%) reduced their cigarette smoking. None of the non-smokers began smoking during the study, and there was no increase in the number of cigarettes smoked among the smokers. There was an increase in the number of patients who engaged in physical activity on a regular basis after the intervention: 56.1% as compared to 42.7% prior to the consultation. This increase was found to be statistically significant (p < 0.001). Among overweight (BMI 25-26.9) and obese (BMI > 27) patients there was a decrease in BMI following the intervention which was found to be statistically significant (p < 0.01). Among patients with normal weight (BMI 20-24.9) and underweight (BMI < 20) there was a decrease in BMI which was not statistically significant.

CONCLUSION

In an era when economic considerations challenge the everyday work of the physician, we have showed in our study that a 20-minute doctor-patient appointment could influence the patient's life-style and thus promote healthy living.

Soluble antagonists to interleukin-1 (IL-1) and tumor necrosis factor (TNF) inhibits loss of tissue attachment in experimental periodontitis

BACKGROUND, AIMS

Periodontal disease is a significant cause of tooth loss among adults and is characterized by the alteration and permanent destruction of the deeper periodontal tissues. Although the presence of pathologic microbes is required to trigger this process, the amplification and progression of the diseased state is believed to rely heavily on the production of host mediators in response to bacteria or their metabolic products. The inflammatory response is effective in preventing large-scale colonization of the gingival tissues by bacteria that lie in close proximity to the tooth surface or within the gingival sulcus. It has been postulated that the host-response in some individuals may lead to an over-reaction to invading oral pathogens resulting in the destruction of periodontal tissues.

METHODS

Several host-derived mediators are believed to contribute to this response. Two agents considered to be essential in periodontal destruction are interleukin-1 (IL-1) and tumor necrosis factor (TNF). We investigated the role of IL-1 and TNF in the loss of connective tissue attachment in a Macaca fascicularis primate model of experimental periodontitis. Silk ligatures impregnated with the periodontal pathogen, Porphyromonas gingivalis were wrapped around the posterior teeth and the activity of IL-1 and TNF were inhibited by soluble receptors to these proinflammatory cytokines via local injection into interdental papillae.

RESULTS

Histomorphometric analysis indicates that IL-1 and TNF antagonists significantly reduced the loss of connective tissue attachment by approximately 51% and the loss of alveolar bone height by almost 91%, both of which were statistically significant.

CONCLUSION

This investigation demonstrates that the loss of connective tissue attachment and progression of periodontal disease can be retarded by antagonists to specific host mediators such as IL-1 and TNF and may provide a potential treatment modality to combat the disease process.

Induction of oocyte maturation by jun-N-terminal kinase (JNK) on the oncogenic ras-p21 pathway is dependent on the raf-MEK signal transduction pathway

PURPOSE

We have previously found that microinjection of activated MEK (mitogen activated kinase kinase) and ERK (mitogen-activated protein; MAP kinase) fails to induce oocyte maturation, but that maturation, induced by oncogenic ras-p21 and insulin-activated cell ras-p21, is blocked by peptides from the ras-binding domain of raf. We also found that jun kinase (JNK), on the stress-activated protein (SAP) pathway, which is critical to the oncogenic ras-p21 signal transduction pathway, is a strong inducer of oocyte maturation. Our purpose in this study was to determine the role of the raf-MEK-MAP kinase pathway in oocyte maturation and how it interacts with JNK from the SAP pathway.

METHODS

We microinjected raf dominant negative mutant mRNA (DN-raf) and the MEK-specific phosphatase, MKP-T4, either together with oncogenic p21 or c-raf mRNA, into oocytes or into oocytes incubated with insulin to determine the effects of these raf-MEK-MAP kinase pathway inhibitors.

RESULTS

We found that oocyte maturation induced by both oncogenic and activated normal p21 is inhibited by both DN-raf and by MKP-T4. The latter more strongly blocks the oncogenic pathway. Also an mRNA encoding a constitutively activated MEK strongly induces oocyte maturation that is not inhibited by DN-raf or by MKP-T4. Surprisingly, we found that oocyte maturation induced by JNK is blocked both by DN-raf and MKP-T4. Furthermore, we discovered that c-raf induces oocyte maturation that is inhibited by glutathione-S-transferase (GST), which we have found to be a potent and selective inhibitor of JNK.

CONCLUSION

We conclude that there is a strong reciprocal interaction between the SAP pathway involving JNK and the raf-MEK-MAP kinase pathway and that oncogenic ras-p21 can be preferentially inhibited by MEK inhibitors. The results imply that blockade of both MEK and JNK-oncogenic ras-p21 interactions may constitute selective synergistic combination chemotherapy against oncogenic ras-induced tumors.

Glutathione-S-Transferase as a selective inhibitor of oncogenic ras-p21-induced mitogenic signaling through blockade of activation of jun by jun-N-terminal kinase

We have identified the intracellular detoxification enzyme, glutathione-S-transferase (GST), as a potent inhibitor of the activation of jun by its kinase, jun-N-terminal kinase (JNK), in vitro. All three major isozymes (alpha, mu, and pi) bind to JNK-jun complexes and inhibit activation of jun by JNK. We now find that GST inhibits JNK-induced oocyte maturation in vivo and strongly inhibits oocyte maturation induced by oncogenic ras-p21 protein, but not by insulin-activated normal cellular p21 protein. These results correlate with the finding that oncogenic, but not insulin-activated normal, p21 induces high levels of activated JNK. GST also strongly blocks induction of oocyte maturation by protein kinase C (PKC) which is a critical downstream target of oncogenic but not normal ras-p21. Thus, we have established a new function for GST as a potent physiological inhibitor of the ras-JNK-jun pathway.

Inhibition of oncogenic and activated wild-type ras-p21 protein-induced oocyte maturation by peptides from the guanine-nucleotide exchange protein, SOS, identified from molecular dynamics calculations. Selective inhibition of oncogenic ras-p21

In the preceding paper we performed molecular dynamics calculations of the average structures of the SOS protein bound to wild-type and oncogenic ras-p21. Based on these calculations, we have identified four major domains of the SOS protein, consisting of residues 631-641, 676-691, 718-729, and 994-1004, which differ in structure between the two complexes. We have now microinjected synthetic peptides corresponding to each of these domains into Xenopus laevis oocytes either together with oncogenic (Val 12)-p21 or into oocytes subsequently incubated with insulin. We find that the first three peptides inhibit both oncogenic and wild-type p21-induced oocyte maturation, while the last peptide much more strongly inhibits oncogenic p21 protein-induced oocyte maturation. These results suggest that each identified SOS region is involved in ras-stimulated signal transduction and that the 994-1004 domain is involved uniquely with oncogenic ras-p21 signaling.

Differentiation of monocytes to macrophages primes cells for lipopolysaccharide stimulation via accumulation of cytoplasmic nuclear factor kappaB

During infection, circulating blood monocytes migrate from the vasculature to the extravascular compartments where they mature into tissue macrophages. The maturation process prepares the cell to actively participate in the inflammatory and the immune responses, and many transcription factors have been found to be involved. Here we report on a novel role for nuclear factor kappaB (NF-kappaB) in this process. Its accumulation in the cytoplasm of differentiated macrophages is responsible for the enhanced ability of the cell to respond to lipopolysaccharide (LPS) stimulation, as determined by tumor necrosis factor alpha (TNF-alpha) secretion. Differentiation of the human monocytic cell line THP-1 into macrophage-like cells was induced by exposure of the cells to phorbol myristate acetate. DNA-bindable NF-kappaB was not detected in the cytoplasm of undifferentiated THP-1 cells but accumulated in the cytoplasm of the cells following differentiation. No TNF-alpha was detected in the media of resting differentiated and nondifferentiated THP-1 cells. Stimulation with LPS of differentiated cells induced the production of higher levels of TNF-alpha than stimulation of nondifferentiated cells. This hyperresponsiveness to LPS was found in the mRNA and secreted TNF-alpha levels. Furthermore, stimulation with LPS induced the translocation of NF-kappaB from the cytoplasm into the nucleus. This translocation process was more rapid in the differentiated cells than in the nondifferentiated cells, and the resultant accumulated levels of NF-kappaB in the nucleus were higher. The DNA-bindable NF-kappaB was identified as a heterodimer of p65 and p50. The results suggest that NF-kappaB accumulation in the cytoplasm during maturation of monocytes to macrophages primes the cells for enhanced responsiveness to LPS and results in the rapid secretion of inflammatory mediators, such as TNF-alpha, by mature macrophages following LPS challenge.

Identification of the site of inhibition of oncogenic ras-p21-induced signal transduction by a peptide from a ras effector domain

We have previously found that a peptide corresponding to residues 35-47 of the ras-p21 protein, from its switch 1 effector domain region, strongly inhibits oocyte maturation induced by oncogenic p21, but not by insulin-activated cellular wild-type p21. Another ras-p21 peptide corresponding to residues 96-110 that blocks ras-jun and jun kinase (JNK) interactions exhibits a similar pattern of inhibition. We have also found that c-raf strongly induces oocyte maturation and that dominant negative c-raf strongly blocks oncogenic p21-induced oocyte maturation. We now find that the p21 35-47, but not the 96-110, peptide completely blocks c-raf-induced maturation. This finding suggests that the 35-47 peptide blocks oncogenic ras at the level of raf; that activated normal and oncogenic ras-p21 have differing requirements for raf-dependent signaling; and that the two oncogenic-ras-selective inhibitory peptides, 35-47 and 96-110, act at two different critical downstream sites, the former at raf the latter at JNK/jun, both of which are required for oncogenic ras-p21 signaling.

Histologic observations of periodontal wound healing after treatment with PerioGlas in nonhuman primates

The effect of PerioGlas (synthetic bone particulate) on wound healing of experimental palatal periodontal defects in monkeys was evaluated. Chronic periodontal defects were created on the palatal aspects of maxillary molars and premolars. Open-flap debridement was performed. Experimental sites received PerioGlas, while control sites received no further treatment. Histologic measurements were performed on new bone, new cementum, epithelial downgrowth, and recession. Results showed significantly more new cementum and less epithelial downgrowth in the sites that received PerioGlas (P < 0.05). The present results indicate that PerioGlas may enhance periodontal wound healing outcomes.

Serum modulation of neutrophil response to Porphyromonas gingivalis LPS in periodontal disease

Rapidly progressive periodontitis is a form of early onset periodontitis characterised by severe gingival inflammation and rapid bone loss. Release of lipopolysaccharide (LPS) from the outer membrane of Gram negative bacteria initiates various biological activities including complement activation, cytotoxicity, and bone resorption. Serum from rapidly progressive periodontitis patients has been reported to enhance the superoxide response of normal neutrophils to lipopolysaccharide purified from Porphyromonas gingivalis, compared to control serum. The purpose of this study was to identify the factor in rapidly progressive periodontitis serum which is responsible for the enhancement of lipopolysaccharide activity. Candidate molecules were considered to be lipopolysaccharide binding protein or antibody to lipopolysaccharide. Lipopolysaccharide binding protein was quantified in serum by ELISA, and rapidly progressive periodontitis sera were found to contain two to three fold more lipopolysaccharide binding protein than control sera. Removal of lipopolysaccharide binding protein from either serum by adsorption to an anti lipopolysaccharide binding protein-sepharose affinity column removed the priming activity of normal neutrophils. Addition of exogenous lipopolysaccharide binding protein to control sera enhanced the priming activity in a dose dependent manner. These results suggest that lipopolysaccharide binding protein in rapidly progressive periodontitis serum may be responsible for enhancement of superoxide generation, which may result in more severe tissue damage in these patients.

Interleukin-1 and tumor necrosis factor activities partially account for calvarial bone resorption induced by local injection of lipopolysaccharide

The present study was undertaken to test the hypothesis that tumor necrosis factor (TNF) and/or interleukin-1 (IL-1) activity mediates lipopolysaccharide (LPS)-induced bone resorption in vivo. To test this hypothesis, Escherichia coli LPS or Porphyromonas gingivalis LPS was injected into the subcutaneous tissues overlying mouse calvariae. Histological sections, prepared from the center of the lesion, were stained for tartrate-resistant acid phosphatase, and histomorphometric analysis was performed to quantify the osteoclast number and the area of bone resorption. In time course experiments using normal mice, a peak of bone resorption occurred 5 days after endotoxin stimulation. In dose-response experiments, IL-1 receptor type 1 deletion (IL-1R(-/-)), TNF double-receptor p55/p75 deletion (TNF p55(-/-)/p75(-/-)), combined TNF p55 and IL-1 receptor type 1 deletion (TNF p55(-/-)/IL-1R(-/-)), and IL-1beta-converting enzyme-deficient (ICE(-/-)) mice and the respective wild-type mice were injected with 500, 100, or 20 micrograms of P. gingivalis LPS and sacrificed 5 days after LPS injection. At the highest dose (500 micrograms), significant decreases in osteoclast number occurred in mutant mice compared to wild-type mice: (i) a 64% reduction for the TNF p55(-/-)/IL-1R(-/-) mice, (ii) a 57% reduction for the IL-1R(-/-) mice, (iii) a 41% reduction for the TNF p55(-/-)/p75(-/-) mice, and (iv) a 38% reduction for the ICE(-/-) mice. At the two lower doses, bone resorption was apparent but no significant differences between mutant and wild-type animals were observed. The present data indicate that at higher doses, LPS-induced bone resorption is substantially mediated by IL-1 and TNF receptor signaling. Furthermore, IL-1 receptor signaling appears to be slightly more important than TNF receptor signaling. At lower LPS doses, other pathways leading to osteoclast activity that are independent of TNF and IL-1 are involved.

Moesin functions as a lipopolysaccharide receptor on human monocytes

Bacterial endotoxin (lipopolysaccharide [LPS]), a glycolipid found in the outer membranes of gram-negative bacteria, induces the secretion of proinflammatory cytokines such as tumor necrosis factor alpha (TNF-alpha), interleukin-1 (IL-1), and IL-6 by monocytes/macrophages. The secretion of these biologically active compounds leads to multiple pathological conditions, such as septic shock. There is substantial evidence that chronic exposure to LPS mediates, at least in part, the tissue destruction associated with gram-negative infection. CD14, a 55-kDa protein, has been identified as an LPS receptor. In conjunction with a serum protein, LPS binding protein (LBP), LPS-CD14 interactions mediate many LPS functions in the inflammatory response. However, CD14 lacks a cytoplasmic domain, or any known signal transduction sequence motif, suggesting the existence of another cell surface domain capable of transducing signals. In this paper, we report a second, CD14-independent LPS binding site, which, based on biological activity, appears to be a functional LPS receptor. Cross-linking experiments were performed to identify LPS binding sites. Two molecules were identified: a 55-kDa protein (CD14) and a second, 78-kDa band. Sequencing of the 78-kDa protein by mass spectroscopic analysis revealed 100% homology with moesin (membrane-organizing extension spike protein). Antibody to CD14 induced partial blocking of the LPS response. However, antimoesin monoclonal antibody completely blocked the LPS-induced TNF-alpha response in human monocytes, without blocking CD14 binding of LPS. Irrelevant isotype controls had no effect. Additional experiments were performed to evaluate the specificity of the antimoesin blocking. Separate experiments evaluated antimoesin effects on monocyte chemotaxis, IL-1 production in response to IL-1 stimulation, and TNF-alpha secretion in response to Staphylococcus aureus stimulation. Antimoesin blocked only LPS-mediated events. The data suggest that moesin functions as an independent LPS receptor on human monocytes. The role of moesin in transduction of CD14-mediated signals is discussed.