Carcinoid abdominal crisis: a case report.

Over the past 40 years, the incidence of neuroendocrine tumors (NETs) has been increasing. Distal small bowel (i.e., midgut) NETs most often cause carcinoid syndrome manifested as cutaneous flushing, diarrhea, bronchial constriction, and cardiac involvement. Carcinoid abdominal crisis occurs when submucosal tumors impede the vascular supply to the gut leading to mesenteric ischemia and worsening abdominal pain. Here, we report the case of a young woman with progressively worsening abdominal pain.

Ferritin and LIC: predicting liver injury in children with sickle cell.

OBJECTIVE: Chronic blood transfusion therapy reduces clinical events in children with sickle cell anemia but increases risk for an iron-related liver injury. Liver biopsy is the gold standard technique for quantifying liver iron content (LIC) and evaluating liver pathology. Ferritin, liver enzymes, and R2* magnetic resonance imaging of the liver are obtained as surrogate markers. In this study we compared surrogate markers with the gold standard, liver biopsy, in assessing liver histology. METHODS: We conducted a retrospective review of 259 liver biopsies in 109 children with sickle cell anemia on chronic transfusion therapy and chelation therapy during a 9-year period at a single center. Liver pathology was compared with LIC, ferritin, and alanine aminotransferase. RESULTS: Ferritin correlates with LIC (r = 0.74, P < 0.001), although there is a broad range of ferritin values for a given LIC. Furthermore, patients with a high LIC (≥7 mg Fe/g dry weight) demonstrated significantly higher ferritin as compared to the patients with lower LIC <7 (P < 0.001). Periportal/portal inflammation also showed a significant relation. There was no significance when comparing ferritin and lobular inflammation or ferritin and alanine aminotransferase. When evaluating LIC in relation to fibrosis, the present study revealed that there was only a significant correlation with severe fibrosis (F = 36, P < 0.001). CONCLUSIONS: The results suggest that although correlations exist among ferritin and LIC and severe fibrosis and LIC, caution should be taken when they are used in isolation. Liver biopsy provides important pathologic information that cannot be obtained through surrogate markers.

lncRNA-056298 Regulates GAP43 and Promotes Cardiac Intrinsic Autonomic Nerve Remodelling in a Canine Model of Atrial Fibrillation Induction after Ganglionated Plexus Ablation.

BACKGROUND: Cardiac intrinsic autonomic nerve remodelling has been reported to play an important role in the recurrence of atrial fibrillation after radiofrequency ablation, which significantly affects the long-term efficacy of this procedure. lncRNAs have been shown to interact in the pathological processes underlying heart diseases. However, the roles and mechanisms of lncRNAs in cardiac intrinsic autonomic nerve remodelling during atrial fibrillation reduction after ganglionated plexus ablation remain unknown. OBJECTIVES: The aim of this study was to investigate the mechanism by which lncRNA- 056298 modulates GAP43 to affect cardiac intrinsic autonomic nerve remodelling and facilitate the induction of atrial fibrillation after ganglionated plexus ablation. METHODS: A canine model of right atrial ganglionated plexus ablation was established. The atrial electrophysiological characteristics and neural markers were detected before and after 6 months of ganglionated plexus ablation. High-throughput sequencing was used to screen differentially expressed lncRNAs in target atrial tissues, and lncRNA- 056298 was selected to further explore its effects and mechanisms on cardiac intrinsic autonomic nerve remodelling. RESULTS: The induction rate of atrial fibrillation increased in dogs after ganglionated plexus ablation. Overexpression of lncRNA-056298 by lentivirus can shorten the atrial effective refractory period and increase the induction of atrial fibrillation. lncRNA- 056298 promoted cardiac intrinsic autonomic nerve remodelling via endogenous competition with cfa-miR-185 to induce transcription of its target gene GAP43, thereby affecting the induction of atrial fibrillation. CONCLUSIONS: lncRNA-056298 regulates GAP43 by sponging miR-185, which affects cardiac intrinsic autonomic nerve remodelling and mediates atrial fibrillation induction after ganglionated plexus ablation.

Malignant potential of small oncocytic follicular carcinoma/Hürthle cell carcinoma: an institutional experience.

AIMS: Oncocytic follicular carcinoma/Hürthle cell carcinoma (OFCA/HCCA) is a rare tumour of the thyroid gland that can be associated with an aggressive clinical course. Most OFCA/HCCAs are large; however, tumours ≤20 mm can occur. The aim of this study was to report our experience with OFCA/HCCA diagnosed at our institution. METHODS AND RESULTS: One hundred and nineteen cases of OFCA/HCCA were included in this study. Data points included age, sex, size of tumour, method of diagnosis, lymph node (LN) status, and clinical follow-up. The cohort included 37 males and 82 females (average age: 55 years). Preoperative fine-needle aspiration (FNA) was performed in 73 (61%) cases. Twenty-five (21%) tumours measured ≤20 mm and 94 (79%) measured >20 mm. Angioinvasion (AI) was present in 48 (40%) cases, and LN metastases (LNMs) in seven (6%) cases; of these, eight (17%) with AI and 1 (2%) with LNMs measured ≤20 mm. Clinical follow-up was available in 74 (62%) cases (range 12-144 months); 13 (17.5%) developed LNMs and six (8%) regional recurrence. Distant metastases (DMs) were seen in 12 (16%) cases. Two cases with DMs and two with LN recurrence measured ≤20 mm. CONCLUSIONS: Oncocytic follicular carcinoma/Hürthle cell carcinoma (OFCA/HCCA) can present as small (≤20 mm) tumours, and can be associated with AI, LNM, and DM.

Expression of SALL4 and SF-1 in gonadoblastoma: useful markers in the identification of the invasive germ cell component.

Gonadoblastoma is a rare gonadal neoplasm composed of primordial germ cells and sex cord-stromal cells and usually occurs in patients with dysgenetic gonads. When patients with gonadoblastoma develop an invasive germ cell tumor, the invasive germ cell component can take the form of dysgerminoma/seminoma, embryonal carcinoma, or yolk sac tumor. In this study, we performed immunohistochemical analysis for SALL4 and steroidogenic factor-1 (SF-1) on 4 cases of gonadoblastoma to examine the expression patterns of these proteins. All of the patients were phenotypically female. One patient had Swyer syndrome, the rest had Turner syndrome. The primordial germ cell component was histologically similar to cells in dysgerminoma/seminoma in these 4 cases. Two patients showed the invasive component-dysgerminoma. As expected, SALL4 stained the germ cells and SF-1 stained the sex cord-stromal cells. There was a clear distinction between the staining patterns of these 2 cell populations. This study demonstrates the utility of SALL4 and SF-1 in determining whether or not there is an invasion in the primordial germ cell component.

Sclerosing epithelioid fibrosarcoma of the pancreas.

Sclerosing epithelioid fibrosarcoma (SEF) is a distinctive variant of fibrosarcoma characterized by epithelioid tumor cells arranged in nests, cords, or sheets embedded within a sclerotic collagenous matrix. It is a relatively newly described malignant fibroblastic tumor, with only fewer than 100 cases reported in English literature. Most cases are located in the lower extremities and limb girdles. Here, we present a case of SEF of the pancreas in a 67-year-old white man and provide a review of literature to date, with emphasis on the differential diagnosis. To our knowledge, this is the first reported case of SEF involving the pancreas.

Intraosseous hibernoma: a potential mimic of metastatic carcinoma.

Intraosseous hibernoma is a rare benign bone tumor, with only 3 cases reported in English literature. In this report, we describe a 50-year-old woman with a history of stage IIB breast cancer and posterolateral right hip pain. Imaging studies showed a sclerotic lesion in the right ilium, which was biopsied and showed mildly thickened bone trabeculae and multivacuolated brown fat cells replacing the normal white fat and hematopoietic elements, diagnostic of intraosseous hibernoma.

Cloaking Mesoporous Polydopamine with Bacterial Membrane Vesicles to Amplify Local and Systemic Antitumor Immunity.

As adjuvants or antigens, bacterial membranes have been widely used in recent antibacterial and antitumor research, but they are often injected multiple times to achieve therapeutic outcomes, with limitations in biosafety and clinical application. Herein, we leverage the biocompatibility and immune activation capacity of Salmonella strain VNP20009 to produce double-layered membrane vesicles (DMVs) for enhanced systemic safety and antitumor immunity. Considering the photothermal effect of polydopamine upon irradiation, VNP20009-derived DMVs are prepared to coat the surface of mesoporous polydopamine (MPD) nanoparticles, leading to the potential synergies between photothermal therapy mediated by MPD and immunotherapy magnified by DMVs. The single dose of MPD@DMV can passively target tumors and activate the immune system with upregulated T cell infiltration and secretion levels of pro-inflammatory factors as well as antitumor related cytokines. All of these promoted immune responses result in malignant melanoma tumor regression and extended survival time on local or distant tumor-bearing mouse models. Importantly, we further explore the advantages of intravenous injection of the MPD@DMV agent compared with its intratumoral injection, and the former demonstrates better long-term immune effects on animal bodies. Overall, this formulation design brings broader prospects for the autologous vaccine adjuvant by bacterial membrane vesicles in cancer therapy.

Single-shot AAV-vectored vaccine against SARS-CoV-2 with fast and long-lasting immunity.

Due to the insufficient long-term protection and significant efficacy reduction to new variants of current COVID-19 vaccines, the epidemic prevention and control are still challenging. Here, we employ a capsid and antigen structure engineering (CASE) strategy to manufacture an adeno-associated viral serotype 6-based vaccine (S663V-RBD), which expresses trimeric receptor binding domain (RBD) of spike protein fused with a biological adjuvant RS09. Impressively, the engineered S663V-RBD could rapidly induce a satisfactory RBD-specific IgG titer within 2 weeks and maintain the titer for more than 4 months. Compared to the licensed BBIBP-CorV (Sinopharm, China), a single-dose S663V-RBD induced more endurable and robust immune responses in mice and elicited superior neutralizing antibodies against three typical SARS-CoV-2 pseudoviruses including wild type, C.37 (Lambda) and B.1.617.2 (Delta). More interestingly, the intramuscular injection of S663V-RBD could overcome pre-existing immunity against the capsid. Given its effectiveness, the CASE-based S663V-RBD may provide a new solution for the current and next pandemic.

A MnAl double adjuvant nanovaccine to induce strong humoral and cellular immune responses.

At present, the most widely used aluminum adjuvants have poor ability to induce effective Th1 type immune responses. Existing evidence suggests that manganese is a potential metal adjuvant by activating cyclic guanosine phospho-adenosine synthase (cGAS)-interferon gene stimulator protein (STING) signaling pathway to enhance humoral and cellular immune response. Hence, the effective modulation of metal components is expected to be a new strategy to improve the efficiency of vaccine immunization. Here, we constructed a manganese and aluminum dual-adjuvant antigen co-delivery system (MnO2-Al-OVA) to enhance the immune responses of subunit vaccines. Namely, the aluminum hydroxide was first fused on the surface of the pre-prepared MnO2 nanoparticles, which were synthesized by a simple redox reaction with potassium permanganate (KMnO4) and oleic acid (OA). The engineered MnO2-Al-OVA could remarkably promote cellular internalization and maturation of dendritic cells. After subcutaneous vaccination, MnO2-Al-OVA rapidly migrated into the lymph nodes (LNs) and efficiently activate the cGAS-STING pathway, greatly induced humoral and cellular immune responses. Of note, our findings underscore the importance of coordination manganese adjuvants in vaccine design by promoting the activation of the cGAS-STING-IFN-I pathway. With a good safety profile and facile preparation process, this dual-adjuvant antigen co-delivery nanovaccine has great potential for clinical translation prospects.

Aluminum nanoparticles deliver a dual-epitope peptide for enhanced anti-tumor immunotherapy.

Tumor peptide vaccines contain only key amino acid sequences of tumor neoantigens, and therefore can provide precise activation of immune responses. Recent research has found that short peptide vaccines restricted to MHC-I epitopes are insufficient to activate effective CD8+ T cell responses for tumor elimination, and assistance from CD4+ T cell immunity could significantly improve the therapeutic outcome. Herein, we proposed an innovative peptide vaccine strategy to simultaneously activate CD8+ and CD4+ T cell responses by combining MHC-I and MHC-II epitopes into one long peptide antigen. To further strengthen the anti-tumor immune response induced by this dual-epitope peptide, we engineered a PEG derivative (PpASE) stabilized aluminum nanoparticle for delivering the synthetic long peptides (ANLs). The synthesized nanovaccine with a diameter of ~100 nm showed good stability and enhanced antigen uptake by antigen-presenting cells (APCs). As a result, ANLs promoted the presentation of MHC-I epitope in APCs and induced stronger activation and proliferation of CD8+ T cells as compared to aluminum nanoparticle loaded with MHC-I epitope restricted peptides (ANSs). After subcutaneous vaccination, the developed nanovaccine significantly inhibited tumor growth and prolonged mouse survival in both B16-OVA and B16F10 tumor models. Finally, ANLs were also able to elevate the maturation level of human dendritic cells (DCs), showing a great possibility of clinical translation.

A dual-responsive nanoplatform with feedback amplification improves antitumor efficacy of photodynamic therapy.

A good photosensitizer (PS) delivery system could enhance the efficiency and reduce the side effects of anti-tumor photodynamic therapy (PDT) by improving accumulation in the tumor, uptake by tumor cells, and intracellular release of the PS. Thus, we rationally developed a multi-stimulus-responsive PS nanocarrier with a double-layered core-shell structure: mPEG-azo-hyaluronic acid-sulfide-Ce6 (PaHAsC). In PaHAsC, the mPEG coat provides protection before entering the hypoxic tumor microenvironment, where mPEG leaves to expose the HA layer. HA then targets overexpressed CD44 on tumor cells for enhanced internalization. Finally, GSH-mediated intracellular release of Ce6 augments ROS generation and O2 consumption under light stimulation. This also aggravates hypoxia in tumor sites to accelerate mPEG removal, forming a positive feedback loop. Data show that PaHAsC dramatically improved the PDT efficacy of Ce6, eliminating most tumors and 80% of tumor-bearing mice survived. With a safe profile, PaHAsC has potential for further development and is a useful example of a PS delivery system.

Nanoparticles with rough surface improve the therapeutic effect of photothermal immunotherapy against melanoma.

Photothermal therapy has been intensively investigated for treating cancer in recent years. However, the long-term therapeutic outcome remains unsatisfying due to the frequently occurred metastasis and recurrence. To address this challenge, immunotherapy has been combined with photothermal therapy to activate anti-tumor immunity and relieve the immunosuppressive microenvironment within tumor sites. Here, we engineered silica-based core‒shell nanoparticles (JQ-1@PSNs-R), in which silica cores were coated with the photothermal agent polydopamine, and a bromodomain-containing protein 4 (BRD4) inhibitor JQ-1 was loaded in the polydopamine layer to combine photothermal and immune therapy for tumor elimination. Importantly, to improve the therapeutic effect, we increased the surface roughness of the nanoparticles by hydrofluoric acid (HF) etching during the fabrication process, and found that the internalization of JQ-1@PSNs-R was significantly improved, leading to a strengthened photothermal killing effect as well as the increased intracellular delivery of JQ-1. In the animal studies, the multifunctional nanoparticles with rough surfaces effectively eradicated melanoma via photothermal therapy, successfully activated tumor-specific immune responses against residual tumor cells, and further prevented tumor metastasis and recurrence. Our results indicated that JQ-1@PSNs-R could serve as an innovative and effective strategy for combined cancer therapy.

Engineering a sustained release vaccine with a pathogen-mimicking manner for robust and durable immune responses.

Sustained release vaccine carriers can facilitate an increased interaction time between the antigen and immune system to strengthen immune responses, but their promotion on adaptive immune responses, especially cellular immunity, are still unfavorable. Herein, we report a sustained antigen delivery vector, which carries abundant antigens, a nucleic acid adjuvant and pathogen-associated molecular patterns to simulate a natural pathogen to reinforce immune responses. Specifically, murine colorectal cancer cells MC38 lysate and Toll-like receptor 9 agonist CpG are loaded into yeast derived ß-glucan particles (GPs). After vaccination, these particles can form a vaccine depot that continuously release the antigen similar to the traditional aluminum hydroxide gel, but recruit more immune cells and induce more cytokine secretion at the injection site. Stronger antibody responses, Th1 and Th17 biased cellular immunity and immune memory are achieved compared with aluminum hydroxide gel. More importantly, treatment with these particles significantly suppress tumor growth in a therapeutic tumor model. This work shed light on the efficacy of combining sustained antigen release with pathogen-mimicking manner in vaccine design.

Albumin-biomineralized nanoparticles to synergize phototherapy and immunotherapy against melanoma.

To date, cancer phototherapy remains as an unsatisfactory method of cancer treatment due to the high probability of cancer recurrence - an effect that is partly driven by tumor-driven immunosuppression. Therefore, we propose inducing adequate immune responses after photo tumor ablation may be critical to achieve a long term therapeutic effect of phototherapy. Here, we engineered the photosensitizer chlorin e6 (Ce6) and the time-honored immunoadjuvant aluminum hydroxide into bovine serum albumin by albumin-based biomineralization as a novel nanosystem (Al-BSA-Ce6 NPs). After intravenous injection, the nanoparticles not only destroyed tumor cells effectively but also protected animals against tumor rechallenge and metastasis by strongly inducing a systemic anti-tumor immune response. Subsequent analysis demonstrated T cells accumulated in lymph nodes and infiltrated the tumor site, elevating levels of immune indicators including serum antibody, cytokine level and higher proportions of cytotoxic T cells and Th1 cells. These protective effects were not observed with commercially available alumina gels, or when the aluminum hydroxide in the nanoparticles was replaced with ferric hydroxide. Therefore, we present Al-BSA-Ce6 NPs as a novel and unique system for alumina adjuvants that serves as an effective approach for cancer therapy.

The LIM protein LIMD1 influences osteoblast differentiation and function.

The balance between bone resorption and bone formation involves the coordinated activities of osteoblasts and osteoclasts. Communication between these two cell types is essential for maintenance of normal bone homeostasis; however, the mechanisms regulating this cross talk are not completely understood. Many factors that mediate differentiation and function of both osteoblasts and osteoclasts have been identified. The LIM protein Limd1 has been implicated in the regulation of stress osteoclastogenesis through an interaction with the p62/sequestosome protein. Here we show that Limd1 also influences osteoblast progenitor numbers, differentiation, and function. Limd1(-/-) calvarial osteoblasts display increased mineralization and accelerated differentiation. While no significant differences in osteoblast number or function were detected in vivo, bone marrow stromal cells isolated from Limd1(-/-) mice contain significantly more osteoblast progenitors compared to wild type controls when cultured ex vivo. Furthermore, we observed a significant increase in nuclear beta-catenin staining in differentiating Limd1(-/-) calvarial osteoblasts suggesting that Limd1 is a negative regulator of canonical Wnt signaling in osteoblasts. These results demonstrate that Limd1 influences not only stress osteoclastogenesis but also osteoblast function and osteoblast progenitor commitment. Together, these data identify Limd1 as a novel regulator of both bone osetoclast and bone osteoblast development and function.

Spatio-Temporal Dynamics of Maize Potential Yield and Yield Gaps in Northeast China from 1990 to 2015.

Maize yield has undergone obvious spatial and temporal changes in recent decades in Northeast China. Understanding how maize potential yield has changed over the past few decades and how large the gaps between potential and actual maize yields are is essential for increasing maize yield to meet increased food demand in Northeast China. In this study, the spatial and temporal dynamics of maize potential yield in Northeast China from 1990 to 2015 were simulated using the Global Agro-ecological Zones (GAEZ) model at the pixel level firstly. Then, the yield gaps between actual and potential yields were analyzed at city scale. The results were the following. (1) The maize potential yield decreased by about 500 kg/ha and the potential production remained at around 260 million tonnes during 1990-2000. From 2000 to 2015, the maize potential yield and production increased by approximately 1000 kg/ha and 80 million tonnes, respectively. (2) The maize potential yield decreased in most regions of Northeast China in the first decade, such as the center area (CA), south area (SA), southwest area (SWA), and small regions in northeast area (NEA), due to lower temperature and insufficient rainfall. The maize potential yield increased elsewhere. (3) The maize potential yield increased by more than 1000 kg/ha in the center area (CA) in the latter 15 years, which may be because of the climate warming and sufficient precipitation. The maize potential yield decreased elsewhere and Harbin in the center area (CA). (4) In 40 cities of Northeast China, the rates of actual yield to potential yield in 17 cities were higher than 80%. The actual yields only attained 50-80% of the potential yields in 20 cities. The gaps between actual and potential yields in Hegang and Dandong were very large, which need to be shrunk urgently. The results highlight the importance of coping with climate change actively, arranging crop structure reasonably, improving farmland use efficiency and ensuring food security in Northeast China.

FHL2 inhibits the activated osteoclast in a TRAF6-dependent manner.

TNF receptor-associated factor 6 (TRAF6) associates with the cytoplasmic domain of receptor activator of NF-kappaB (RANK). This event is central to normal osteoclastogenesis. We discovered that TRAF6 also interacts with FHL2 (four and a half LIM domain 2), a LIM domain--only protein that functions as a transcriptional coactivator or corepressor in a cell-type--specific manner. FHL2 mRNA and protein are undetectable in marrow macrophages and increase pari passu with osteoclast differentiation in vitro. FHL2 inhibits TRAF6-induced NF-kappaB activity in wild-type osteoclast precursors and, in keeping with its role as a suppressor of TRAF6-mediated RANK signaling, TRAF6/RANK association is enhanced in FHL2-/- osteoclasts. FHL2 overexpression delays RANK ligand-induced (RANKL-induced) osteoclast formation and cytoskeletal organization. Interestingly, osteoclast-residing FHL2 is not detectable in naive wild-type mice, in vivo, but is abundant in those treated with RANKL and following induction of inflammatory arthritis. Reflecting increased RANKL sensitivity, osteoclasts generated from FHL2-/- mice reach maturation and optimally organize their cytoskeleton earlier than their wild-type counterparts. As a consequence, FHL2-/- osteoclasts are hyperresorptive, and mice lacking the protein undergo enhanced RANKL and inflammatory arthritis-stimulated bone loss. FHL2 is, therefore, an antiosteoclastogenic molecule exerting its effect by attenuating TRAF6-mediated RANK signaling.

Transalveolar sinus floor lift without bone grafting in atrophic maxilla: A meta-analysis.

We performed a meta-analysis aimed to assess the clinical results after transalveolar sinus floor lift without bone grafting in the atrophic maxilla. A systematic electronic literature search was conducted in PubMed, Embase and The Cochrane Library, followed by a manual search. Two reviewers independently extracted study data and conducted quality assessments. Ten non-controlled studies including 1484 implants and eight controlled studies (5 RCTs and 3 prospective studies) including 817 implants (451 implants in the non-graft group) were enrolled in this study. The survival rate of implants via the graft-free method was 98% (95%CI 96% to 100%). There was no significant difference in the survival rate between the non-graft group and the graft group (RR: 1.02; p = 0.18). No statistically significant difference in marginal bone loss was detected between the groups at 12 months (0.57, p = 0.07) or 36 months (0.05, p = 0.61). The endo-sinus bone gain in the non-graft group was significantly lower than in the graft group at 12 months (-1.10, p = 0.0001) and 36 months (-0.74, p = 0.02). Hence, the available evidence suggests that predictable results could be acquired through transalveolar sinus floor lift without bone grafting, while there may be a trend toward more endo-sinus bone gain with bone grafts.

Four and half lim protein 2 (FHL2) stimulates osteoblast differentiation.

UNLABELLED: FHL2, a molecule that interacts with many integrins and transcription factors, was found to play an important role in osteoblast differentiation. Overexpression of FHL2 increases the accumulation of osteoblast differentiation markers and matrix mineralization, whereas FHL2 deficiency results in inhibition of osteoblast differentiation and decreased bone formation. INTRODUCTION: Integrin-matrix interaction plays a critical role in osteoblast function. It has been shown that the cytoplasmic domains of integrin beta subunits mediate signal transduction induced by integrin-matrix interaction. We reasoned that the identification of proteins interacting with beta-cytoplasmic tails followed by analysis of the function of these proteins would enhance our understanding on integrin signaling and the roles of these proteins in osteoblast activities. MATERIALS AND METHODS: Yeast two hybrid assay was used to identify proteins interacting with the cytoplasmic domain of integrin beta5 subunit. The association of these proteins with integrin alphavbeta5 was confirmed by confocal analysis and co-immunoprecipitation. A stable MC3T3-E1 cells line overexpressing Four and Half Lim Protein 2 (FHL2) and mouse osteoblasts deficient in FHL2 were used to study the roles of FHL2 in osteoblast differentiation and bone formation. Matrix protein expression was determined by mRNA analysis and Western blotting. Matrix mineralization was detected by Alizarin red staining. Alkaline phosphatase activity was also measured. muCT was used to determine bone histomorphometry. RESULTS AND CONCLUSIONS: FHL2 and actin-binding proteins, palladin and filamin A, were identified as proteins interacting with beta5 cytoplasmic domain. FHL2 co-localized with alphavbeta5 at the focal adhesion sites in association with palladin and filamin A. FHL2 was also present in nuclei. Osteoblasts overexpressing FHL2 exhibited increased adhesion to and migration on matrix proteins. Conversely, FHL2 stimulation of CREB activity was dependent on integrin function because it was inhibited by Gly-Arg-Gly-Asp-Ser (GRGDS) peptide. The expression of osteoblast differentiation markers and Msx2 was upregulated, and bone matrix mineralization was increased in FHL2 overexpressing cells. In contrast, FHL2-deficient bone marrow cells and osteoblasts displayed decreased osteoblast colony formation and differentiation, respectively, compared with wildtype cells. Moreover, FHL2-deficient female mice exhibited greater bone loss than the wildtype littermates after ovariectomy. Thus, FHL2 plays an important role in osteoblast differentiation and bone formation.