Radiosensitization of Allogenic Subcutaneous C6 Glioma Model with Focused Ultrasound-Induced Mild Hyperthermia.

The radiosensitization potential of focused ultrasound (FUS)-induced mild hyperthermia was assessed in an allogenic subcutaneous C6 glioma tumor model in rats. Mild hyperthermia at 42 °C was induced in tumors using a single-element 350 kHz FUS transducer. Radiation was delivered with a small animal radiation research platform using a single-beam irradiation technique. The combined treatment involved 20 min of FUS hyperthermia immediately before radiation. Tumor growth changes were observed one week post-treatment. A radiation dose of 2 Gy alone showed limited tumor control (30% reduction). However, when combined with FUS hyperthermia, there was a significant reduction in tumor growth compared to other treatments (tumor volumes: control-1174 ± 554 mm3, FUS-HT-1483 ± 702 mm3, 2 Gy-609 ± 300 mm3, FUS-HT + 2 Gy-259 ± 186 mm3; ANOVA p < 0.00001). Immunohistological analysis suggested increased DNA damage as a short-term mechanism for tumor control in the combined treatment. In conclusion, FUS-induced mild hyperthermia can enhance the effectiveness of radiation in a glioma tumor model, potentially improving the outcome of standard radiation treatments for better tumor control.

Proximal immune-epithelial progenitor interactions drive chronic tissue sequelae post COVID-19.

The long-term physiological consequences of SARS-CoV-2, termed Post-Acute Sequelae of COVID-19 (PASC), are rapidly evolving into a major public health concern. The underlying cellular and molecular etiology remain poorly defined but growing evidence links PASC to abnormal immune responses and/or poor organ recovery post-infection. Yet, the precise mechanisms driving non-resolving inflammation and impaired tissue repair in the context of PASC remain unclear. With insights from three independent clinical cohorts of PASC patients with abnormal lung function and/or viral infection-mediated pulmonary fibrosis, we established a clinically relevant mouse model of post-viral lung sequelae to investigate the pathophysiology of respiratory PASC. By employing a combination of spatial transcriptomics and imaging, we identified dysregulated proximal interactions between immune cells and epithelial progenitors unique to the fibroproliferation in respiratory PASC but not acute COVID-19 or idiopathic pulmonary fibrosis (IPF). Specifically, we found a central role for lung-resident CD8+ T cell-macrophage interactions in maintaining Krt8hi transitional and ectopic Krt5+ basal cell progenitors, thus impairing alveolar regeneration and driving fibrotic sequelae after acute viral pneumonia. Mechanistically, CD8+ T cell derived IFN-γ and TNF stimulated lung macrophages to chronically release IL-1ß, resulting in the abnormal accumulation of dysplastic epithelial progenitors and fibrosis. Notably, therapeutic neutralization of IFN-γ and TNF, or IL-1ß after the resolution of acute infection resulted in markedly improved alveolar regeneration and restoration of pulmonary function. Together, our findings implicate a dysregulated immune-epithelial progenitor niche in driving respiratory PASC. Moreover, in contrast to other approaches requiring early intervention, we highlight therapeutic strategies to rescue fibrotic disease in the aftermath of respiratory viral infections, addressing the current unmet need in the clinical management of PASC and post-viral disease.

Proximal immune-epithelial progenitor interactions drive chronic tissue sequelae post COVID-19.

The long-term physiological consequences of SARS-CoV-2, termed Post-Acute Sequelae of COVID-19 (PASC), are rapidly evolving into a major public health concern. The underlying cellular and molecular etiology remain poorly defined but growing evidence links PASC to abnormal immune responses and/or poor organ recovery post-infection. Yet, the precise mechanisms driving non-resolving inflammation and impaired tissue repair in the context of PASC remain unclear. With insights from three independent clinical cohorts of PASC patients with abnormal lung function and/or viral infection-mediated pulmonary fibrosis, we established a clinically relevant mouse model of post-viral lung sequelae to investigate the pathophysiology of respiratory PASC. By employing a combination of spatial transcriptomics and imaging, we identified dysregulated proximal interactions between immune cells and epithelial progenitors unique to the fibroproliferation in respiratory PASC but not acute COVID-19 or idiopathic pulmonary fibrosis (IPF). Specifically, we found a central role for lung-resident CD8+ T cell-macrophage interactions in maintaining Krt8hi transitional and ectopic Krt5+ basal cell progenitors, thus impairing alveolar regeneration and driving fibrotic sequelae after acute viral pneumonia. Mechanistically, CD8+ T cell derived IFN-γ and TNF stimulated lung macrophages to chronically release IL-1ß, resulting in the abnormal accumulation of dysplastic epithelial progenitors and fibrosis. Notably, therapeutic neutralization of IFN-γ and TNF, or IL-1ß after the resolution of acute infection resulted in markedly improved alveolar regeneration and restoration of pulmonary function. Together, our findings implicate a dysregulated immune-epithelial progenitor niche in driving respiratory PASC. Moreover, in contrast to other approaches requiring early intervention, we highlight therapeutic strategies to rescue fibrotic disease in the aftermath of respiratory viral infections, addressing the current unmet need in the clinical management of PASC and post-viral disease.

Periostin+ Stromal Cells Guide Lymphovascular Invasion by Cancer Cells.

Cancer cell dissemination to sentinel lymph nodes is associated with poor patient outcomes, particularly in breast cancer. The process by which cancer cells egress from the primary tumor upon interfacing with the lymphatic vasculature is complex and driven by dynamic interactions between cancer cells and stromal cells, including cancer-associated fibroblasts (CAF). The matricellular protein periostin can distinguish CAF subtypes in breast cancer and is associated with increased desmoplasia and disease recurrence in patients. However, as periostin is secreted, periostin-expressing CAFs are difficult to characterize in situ, limiting our understanding of their specific contribution to cancer progression. Here, we used in vivo genetic labeling and ablation to lineage trace periostin+ cells and characterize their functions during tumor growth and metastasis. Periostin-expressing CAFs were spatially found at periductal and perivascular margins, were enriched at lymphatic vessel peripheries, and were differentially activated by highly metastatic cancer cells versus poorly metastatic counterparts. Surprisingly, genetically depleting periostin+ CAFs slightly accelerated primary tumor growth but impaired intratumoral collagen organization and inhibited lymphatic, but not lung, metastases. Periostin ablation in CAFs impaired their ability to deposit aligned collagen matrices and inhibited cancer cell invasion through collagen and across lymphatic endothelial cell monolayers. Thus, highly metastatic cancer cells mobilize periostin-expressing CAFs in the primary tumor site that promote collagen remodeling and collective cell invasion within lymphatic vessels and ultimately to sentinel lymph nodes. SIGNIFICANCE: Highly metastatic breast cancer cells activate a population of periostin-expressing CAFs that remodel the extracellular matrix to promote escape of cancer cells into lymphatic vessels and drive colonization of proximal lymph nodes.

Mapping the Immune Cell Microenvironment with Spatial Profiling in Muscle Tissue Injected with the Venom of Daboia russelii.

Pathological and inflammatory events in muscle after the injection of snake venoms vary in different regions of the affected tissue and at different time intervals. In order to study such heterogeneity in the immune cell microenvironment, a murine model of muscle necrosis based on the injection of the venom of Daboia russelii was used. Histological and immunohistochemical methods were utilized to identify areas in muscle tissue with a different extent of muscle cell damage, based on the presence of hypercontracted muscle cells, a landmark of necrosis, and on the immunostaining for desmin. A gradient of inflammatory cells (neutrophils and macrophages) was observed from heavily necrotic areas to less damaged and non-necrotic areas. GeoMx® Digital Spatial Profiler (NanoString, Seattle, WA, USA) was used for assessing the presence of markers of various immune cells by comparing high-desmin (nondamaged) and low-desmin (damaged) regions of muscle. Markers of monocytes, macrophages, M2 macrophages, dendritic cells, neutrophils, leukocyte adhesion and migration markers, and hematopoietic precursor cells showed higher levels in low-desmin regions, especially in samples collected 24 hr after venom injection, whereas several markers of lymphocytes did not. Moreover, apoptosis (BAD) and extracellular matrix (fibronectin) markers were also increased in low-desmin regions. Our findings reveal a hitherto-unknown picture of immune cell microheterogeneity in venom-injected muscle which greatly depends on the extent of muscle cell damage and the time lapse after venom injection.

Increased IgG4+ plasma cells are common in excised lymph nodes from children and adolescents without IgG4-related disease.

Lymphadenopathy is a common finding in patients with IgG4-related disease (IgG4-RD) and often associated with increased IgG4+ plasma cells in this setting. The histologic features of so-called IgG4-related lymphadenopathy (IgG4-LAD) have seldom been investigated in children and adolescents, and step-wise progression to extranodal IgG4-RD has not been described. This study was performed to further evaluate the frequency, pathologic features, and clinical significance of IgG4-LAD-like histologic changes in the pediatric setting. We analyzed 37 benign lymph nodes collected semi-consecutively from children aged 0-18 years at our institution for both absolute and relative IgG4+ plasma cell abundance and recurrent histomorphologic patterns associated with IgG4-LAD. The combination of IgG4+/IgG+ plasma cell ratio >40% and IgG4+ plasma cell count ≥50 were considered as IgG4-LAD-like per expert consensus guidelines. Seven cases (19%) met both diagnostic criteria. The dominant histomorphologic patterns were follicular hyperplasia (n = 6), interfollicular expansion (n = 3), and progressive transformation of germinal centers (n = 3). Extranodal manifestations of IgG4-RD were not identified in this cohort (38 months average follow-up). Instead, clinical and laboratory findings indicated that lymph node enlargement in most patients could likely be attributed to alternative processes including antecedent dentistry, concurrent infection, and incipient Crohn's disease. Our findings suggest that the histologic features of IgG4-LAD are likely much more common in children and adolescents than previously recognized, often existing in complex with common reactive lymphadenopathies. The diagnostic value of routine immunohistochemical assessment for IgG4+ plasma cells in benign lymph nodes from pediatric patients without established extranodal IgG4-RD and/or other supportive clinical and laboratory data is therefore uncertain.

Loss of TDP-43 in male germ cells causes meiotic failure and impairs fertility in mice.

Meiotic arrest is a common cause of human male infertility, but the causes of this arrest are poorly understood. Transactive response DNA-binding protein of 43 kDa (TDP-43) is highly expressed in spermatocytes in the preleptotene and pachytene stages of meiosis. TDP-43 is linked to several human neurodegenerative disorders wherein its nuclear clearance accompanied by cytoplasmic aggregates underlies neurodegeneration. Exploring the functional requirement for TDP-43 for spermatogenesis for the first time, we show here that conditional KO (cKO) of the Tardbp gene (encoding TDP-43) in male germ cells of mice leads to reduced testis size, depletion of germ cells, vacuole formation within the seminiferous epithelium, and reduced sperm production. Fertility trials also indicated severe subfertility. Spermatocytes of cKO mice showed failure to complete prophase I of meiosis with arrest at the midpachytene stage. Staining of synaptonemal complex protein 3 and γH2AX, markers of the meiotic synaptonemal complex and DNA damage, respectively, and super illumination microscopy revealed nonhomologous pairing and synapsis defects. Quantitative RT-PCR showed reduction in the expression of genes critical for prophase I of meiosis, including Spo11 (initiator of meiotic double-stranded breaks), Rec8 (meiotic recombination protein), and Rad21L (RAD21-like, cohesin complex component), as well as those involved in the retinoic acid pathway critical for entry into meiosis. RNA-Seq showed 1036 upregulated and 1638 downregulated genes (false discovery rate <0.05) in the Tardbp cKO testis, impacting meiosis pathways. Our work reveals a crucial role for TDP-43 in male meiosis and suggests that some forms of meiotic arrest seen in infertile men may result from the loss of function of TDP-43.

Glioma-Associated Oncogene-1 Expression in Basal Cell Carcinoma and Its Histologic Mimics.

ABSTRACT: Basal cell carcinoma (BCC) is the most common skin cancer, and it has numerous histologic mimics with variable prognoses and treatments. Although some immunohistochemical stains can be used for the differential diagnosis of BCC, variability and overlap in results can complicate their interpretation. Immunohistochemical staining for glioma-associated oncogene-1 (Gli-1) was performed on 26 nodular BCCs, 22 infiltrative BCCs, 9 basaloid squamous cell carcinomas, 12 desmoplastic trichoepitheliomas, 19 Merkel cell carcinomas, 11 sebaceous carcinomas, 10 cylindromas, 14 spiradenomas, 12 adenoid cystic carcinomas (AdCC), and 1 solitary trichoepithelioma. Strength of staining was scored as 0, 1+, 2+, or 3+, and distribution of staining was categorized as diffuse, multifocal, or focal. Strong, diffuse Gli-1 expression was seen in all tumors with basal epidermal-type differentiation, including BCC, trichoepithelioma, and basaloid squamous cell carcinoma. All examples of Merkel cell carcinoma were negative for cytoplasmic expression. Seven out of 11 sebaceous carcinomas were negative for Gli-1, and the remaining 4 showed 1+ expression. Cylindroma, spiradenoma, and AdCC, each an adnexal skin tumor, showed the most variable staining, but with cylindroma and spiradenoma demonstrating comparable labeling patterns. Overall, although Gli-1 may not distinguish between basal epidermal-type tumors, it may have a role in separating that group from lesions with adnexal differentiation, particularly sebaceous carcinoma, but also cylindroma, spiradenoma, and AdCC. Any cytoplasmic staining seems to exclude the diagnosis of Merkel cell carcinoma.

IL-33 drives group 2 innate lymphoid cell-mediated protection during Clostridium difficile infection.

Clostridium difficile (C. difficile) incidence has tripled over the past 15 years and is attributed to the emergence of hypervirulent strains. While it is clear that C. difficile toxins cause damaging colonic inflammation, the immune mechanisms protecting from tissue damage require further investigation. Through a transcriptome analysis, we identify IL-33 as an immune target upregulated in response to hypervirulent C. difficile. We demonstrate that IL-33 prevents C. difficile-associated mortality and epithelial disruption independently of bacterial burden or toxin expression. IL-33 drives colonic group 2 innate lymphoid cell (ILC2) activation during infection and IL-33 activated ILC2s are sufficient to prevent disease. Furthermore, intestinal IL-33 expression is regulated by the microbiota as fecal microbiota transplantation (FMT) rescues antibiotic-associated depletion of IL-33. Lastly, dysregulated IL-33 signaling via the decoy receptor, sST2, predicts C. difficile-associated mortality in human patients. Thus, IL-33 signaling to ILC2s is an important mechanism of defense from C. difficile colitis.

Sub-terahertz vibrational spectroscopy of ovarian cancer and normal control tissue for molecular diagnostic technology.

We introduce here recently developed highly resolved Sub-Terahertz resonance spectroscopy of biological molecules and cells combined with molecular dynamics (MD) computational analysis as a new approach for optical visualization and quantification of the presence of microRNAs, particularly the mir-200 family, as potential biomarkers in samples from tissue of epithelial ovarian cancers for disease early detection, analysis, prognosis and treatment.METHOD: A set of samples for this study was prepared from anonymized archival formalin-fixed, paraffin-embedded ovarian epithelial tissue containing regions of invasive neoplastic cells from cases of high-histologic grade serous papillary ovarian carcinoma. Control samples were normal mucosa from fallopian tubes of patients with no known malignancy. Spectroscopic characterization of tissue samples in this study was performed using a continuous wave, frequency domain automated spectrometer operating at room temperature in the spectral region of 310-500 GHz. The spectral results were compared with molecular dynamics simulations and absorption coefficient calculations utilized to predict the absorption spectra.RESULTS: The characteristic spectroscopic features in absorption spectra, particularly the presence of absorption peaks near 13 cm-1 have been identified as cancer indicators. Tissue samples heterogeneity, reflected by diverse spectral signatures, provides additional, very specific information that may be used for identification of cancer subtypes, clinical behavior or sensitivity to specific therapies. Further work is warranted to determine if this signature can be detected in bio-fluids from ovarian cancer patients. If strongly correlated with cancer burden, it may then be investigated as a potential new biomarker for disease monitoring, and also perhaps as a biomarker for cancer screening.

Microbiome-mediated neutrophil recruitment via CXCR2 and protection from amebic colitis.

The disease severity of Entamoeba histolytica infection ranges from asymptomatic to life-threatening. Recent human and animal data implicate the gut microbiome as a modifier of E. histolytica virulence. Here we have explored the association of the microbiome with susceptibility to amebiasis in infants and in the mouse model of amebic colitis. Dysbiosis occurred symptomatic E. histolytica infection in children, as evidenced by a lower Shannon diversity index of the gut microbiota. To test if dysbiosis was a cause of susceptibility, wild type C57BL/6 mice (which are innately resistant to E. histiolytica infection) were treated with antibiotics prior to cecal challenge with E. histolytica. Compared with untreated mice, antibiotic pre-treated mice had more severe colitis and delayed clearance of E. histolytica. Gut IL-25 and mucus protein Muc2, both shown to provide innate immunity in the mouse model of amebic colitis, were lower in antibiotic pre-treated mice. Moreover, dysbiotic mice had fewer cecal neutrophils and myeloperoxidase activity. Paradoxically, the neutrophil chemoattractant chemokines CXCL1 and CXCL2, as well as IL-1ß, were higher in the colon of mice with antibiotic-induced dysbiosis. Neutrophils from antibiotic pre-treated mice had diminished surface expression of the chemokine receptor CXCR2, potentially explaining their inability to migrate to the site of infection. Blockade of CXCR2 increased susceptibility of control non-antibiotic treated mice to amebiasis. In conclusion, dysbiosis increased the severity of amebic colitis due to decreased neutrophil recruitment to the gut, which was due in part to decreased surface expression on neutrophils of CXCR2.

Immunolocalization of TAR DNA-binding protein of 43 kDa (TDP-43) in mouse seminiferous epithelium.

TAR DNA-binding protein of 43 kDa (TDP-43) is an evolutionarily conserved, ubiquitously expressed, multi-functional DNA/RNA-binding protein with roles in gene transcription, mRNA splicing, stability, transport, micro RNA biogenesis, and suppression of transposons. Aberrant expression of TDP-43 in testis and sperm was recently shown to be associated with male infertility, which highlights the need to understand better the expression of TDP-43 in the testis. We previously cloned TDP-43 from a mouse testis cDNA library, and showed that it functions as a transcriptional repressor and regulates the precise spatiotemporal expression of the Acrv1 gene, which encodes the acrosomal protein SP-10, during spermatogenesis. Here, we performed immunoblotting and immunohistochemistry of the mouse testis using four separate antibodies recognizing the amino and carboxyl termini of TDP-43. TDP-43 is present in the nuclei of germ cells as well as Sertoli cells. TDP-43 expression begins in type B/intermediate spermatogonia, peaks in preleptotene spermatocytes, and becomes undetectable in leptotene and zygotene spermatocytes. Pachytene spermatocytes and early round spermatids again express TDP-43, but its abundance diminishes later in spermatids (at steps 5-8). Interestingly, two of the four antibodies showed TDP-43 expression in spermatids at steps 9-10, which coincides with the initial phase of the histone-to-protamine transition. Immunoreactivity patterns observed in the study suggest that TDP-43 assumes different conformational states at different stages of spermatogenesis. TDP-43 pathology has been extensively studied in the context of neurodegenerative diseases; its role in spermatogenesis warrants further detailed investigation of the involvement of TDP-43 in male infertility.

Egress of sperm autoantigen from seminiferous tubules maintains systemic tolerance.

Autoimmune responses to meiotic germ cell antigens (MGCA) that are expressed on sperm and testis occur in human infertility and after vasectomy. Many MGCA are also expressed as cancer/testis antigens (CTA) in human cancers, but the tolerance status of MGCA has not been investigated. MGCA are considered to be uniformly immunogenic and nontolerogenic, and the prevailing view posits that MGCA are sequestered behind the Sertoli cell barrier in seminiferous tubules. Here, we have shown that only some murine MGCA are sequestered. Nonsequestered MCGA (NS-MGCA) egressed from normal tubules, as evidenced by their ability to interact with systemically injected antibodies and form localized immune complexes outside the Sertoli cell barrier. NS-MGCA derived from cell fragments that were discarded by spermatids during spermiation. They egressed as cargo in residual bodies and maintained Treg-dependent physiological tolerance. In contrast, sequestered MGCA (S-MGCA) were undetectable in residual bodies and were nontolerogenic. Unlike postvasectomy autoantibodies, which have been shown to mainly target S-MGCA, autoantibodies produced by normal mice with transient Treg depletion that developed autoimmune orchitis exclusively targeted NS-MGCA. We conclude that spermiation, a physiological checkpoint in spermatogenesis, determines the egress and tolerogenicity of MGCA. Our findings will affect target antigen selection in testis and sperm autoimmunity and the immune responses to CTA in male cancer patients.

Cyclin D1 expression and polysomy in lymphocyte-predominant cells of nodular lymphocyte-predominant Hodgkin lymphoma.

Cyclin D1 protein expression in lymphocytes is classically associated with mantle cell lymphoma. Although increasingly recognized in other lymphoproliferative disorders, cyclin D1 expression and CCND1 gene abnormalities have not been well studied in nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL). Using a double stain for CD20/cyclin D1, we quantified cyclin D1 expression in 10 cases of NLPHL and correlated those findings with SOX11 expression, CCND1 gene abnormalities, and clinical data. For comparison, we examined 5 cases of T cell-/histiocyte-rich large B-cell lymphoma (THRLBCL). All cases of NLPHL stained for cyclin D1 showed at least rare positivity in lymphocyte-predominant (LP) cells. In 4 cases, at least 20% of LP cells were positive for CD20/cyclin D1. Neither SOX11 expression nor CCND1 gene rearrangement was found in any of the cases, but fluorescence in situ hybridization showed a proportion of the large cells with 3 to 4 copies of nonfused IGH and CCND1 signals or 3 intact CCND1 break-apart signals. Further study with CCND1/CEP11 showed polysomy in 6 of 9 cases with cyclin D1 expression and 5 of 16 NLPHL not examined for cyclin D1. Two of 5 cases of THRLBCL showed rare positive staining for CD20/cyclin D1; 1 case showed polysomy with CCND1/CEP11. Results show that cyclin D1 may be expressed in LP cells without SOX11 expression or CCND1 translocation. Polysomy with increased copies of CCND1 may account for cyclin D1 expression in some cases. Cyclin D1 expression is not useful for distinguishing NLPHL from THRLBCL and has no apparent clinical significance in NLPHL.

Microbiota-Regulated IL-25 Increases Eosinophil Number to Provide Protection during Clostridium difficile Infection.

Clostridium difficile infection (CDI) is the most common cause of hospital-acquired infection in the United States. Host susceptibility and the severity of infection are influenced by disruption of the microbiota and the immune response. However, how the microbiota regulate immune responses to mediate CDI outcome remains unclear. Here, we have investigated the role of the microbiota-linked cytokine IL-25 during infection. Intestinal IL-25 was suppressed during CDI in humans and mice. Restoration of IL-25 reduced CDI-associated mortality and tissue pathology even though equivalent levels of C. difficile bacteria and toxin remained in the gut. IL-25 protection was mediated by gut eosinophils, as demonstrated by an increase in intestinal eosinophils and a loss of IL-25 protection upon eosinophil depletion. These findings support a mechanism whereby the induction of IL-25-mediated eosinophilia can reduce host mortality during active CDI. This work may provide targets for future development of microbial or immune-based therapies.

Effects of n-3 fish oil on metabolic and histological parameters in NASH: a double-blind, randomized, placebo-controlled trial.

BACKGROUND & AIMS: This study's aim was to assess the histological and metabolic effects of n-3 polyunsaturated fatty acids (PUFAs) vs. placebo while adjusting for the impact of age and weight change in NASH patients. (ClinicalTrials.gov: NCT00681408). METHODS: Forty-one subjects with non-cirrhotic NASH were enrolled, and 34 completed the study. 17 received n-3 fish oil 3000 mg/day and 17 received placebo daily for 1 year with typical counselling on caloric intake and physical activity for all subjects. RESULTS: N-3- and placebo-treated groups showed no significant difference for the primary end point of NASH activity score (NAS) reduction ⩾ 2 points without fibrosis progression after adjustment for known covariates (n-3, 4/17 (23.5%); placebo, 3/17, (17.6%), p = 0.99). Among subjects with increased or stable weight, n-3 subjects showed a larger decrease in liver fat content by MRI than placebo-treated subjects (p = 0.014 for 2nd quartile, p = 0.003 for 3rd quartile of weight change). N-3 treatment showed significant fat reduction on the paired analysis of image-assisted fat morphometry regardless of weight loss or gain. Exercise capacity remained markedly reduced in all subjects. No independent effects on markers of hepatocyte injury or insulin sensitivity indices were observed. CONCLUSION: N-3 PUFAs at 3000 mg/day for one year did not lead to an improvement in the primary outcome of histological activity in NASH patients (⩾ 2 point NAS reduction). N-3 led to reduced liver fat by multiple measures. Other metabolic effects were not seen, although no detrimental effects were apparent. Whether longer duration, higher dose, or different composition of n-3 therapy would lead to additional benefits is uncertain.

The acrosomal protein SP-10 (Acrv1) is an ideal marker for staging of the cycle of seminiferous epithelium in the mouse.

The study of spermatogenesis requires accurate identification of the stages of the cycle of the seminiferous epithelium. A stage refers to the unique association of germ cell types at a particular phase of development, as seen in a cross-sectioned seminiferous tubule. Stage-identification, however, is a daunting task. There are 12 stages represented in the mouse seminiferous epithelium. Stages are typically identified on the basis of the morphology of the developing acrosome of spermatids. Although the characteristic features of the acrosome are well-documented in ultrastructure images, a reagent that can highlight the subtle differences in acrosome shape under the light microscope is lacking. Here we demonstrate that a polyclonal antibody raised against the mouse acrosomal protein SP-10 is extremely useful for stage identification. Immunohistochemistry showed that the anti-SP-10 antibody is highly specific for the acrosome of spermatids, as no other cell type in the epithelium showed immunoreactivity. At lower magnification, the gross shape of the acrosome and the increasing intensity of immunostaining served as a guide for the identification of stages I-XII. At higher magnification, characteristic morphological features-such as whether the part of the acrosome that contacts the nuclear surface is round (stage III) or flat (stage IV) or curved (stage VI)-could be identified unambiguously. Overall, we present evidence that SP-10 is a useful marker for staging the cycle of the seminiferous epithelium. The anti-SP-10 antibody works well in different fixatives, on paraffin-embedded as well as cryosections, and has been shown to be useful for characterizing spermatogenic defects in mutant mice.

Role of leptin-mediated colonic inflammation in defense against Clostridium difficile colitis.

The role of leptin in the mucosal immune response to Clostridium difficile colitis, a leading cause of nosocomial infection, was studied in humans and in a murine model. Previously, a mutation in the receptor for leptin (LEPR) was shown to be associated with susceptibility to infectious colitis and liver abscess due to Entamoeba histolytica as well as to bacterial peritonitis. Here we discovered that European Americans homozygous for the same LEPR Q223R mutation (rs1137101), known to result in decreased STAT3 signaling, were at increased risk of C. difficile infection (odds ratio, 3.03; P = 0.015). The mechanism of increased susceptibility was studied in a murine model. Mice lacking a functional leptin receptor (db/db) had decreased clearance of C. difficile from the gut lumen and diminished inflammation. Mutation of tyrosine 1138 in the intracellular domain of LepRb that mediates signaling through the STAT3/SOCS3 pathway also resulted in decreased mucosal chemokine and cell recruitment. Collectively, these data support a protective mucosal immune function for leptin in C. difficile colitis partially mediated by a leptin-STAT3 inflammatory pathway that is defective in the LEPR Q223R mutation. Identification of the role of leptin in protection from C. difficile offers the potential for host-directed therapy and demonstrates a connection between metabolism and immunity.

Role of interleukin 23 signaling in Clostridium difficile colitis.

Clostridium difficile is currently the leading cause of hospital-acquired infections in the United States. Here, we observed increased interleukin 23 (IL-23) protein levels in human colon biopsy specimens positive for C. difficile toxins, compared with levels in negative controls (P = .008) We also investigated the role of IL-23 during C. difficile infection, using 2 distinct murine models. Mice lacking IL-23 signaling had a significant increase in survival (100% [12 mice]), compared with control mice (16.7%-50% [12 mice]). These data suggest a new potential drug target for human C. difficile treatment and indicate the first link between IL-23 and disease severity during murine infection.

A novel near-infrared fluorescence imaging probe for in vivo neutrophil tracking.

The development and validation of a multiscopic near-infrared fluorescence (NIRF) probe, cinnamoyl-F-(D)L-F-(D)L-F-PEG-cyanine7 (cFlFlF-PEG-Cy7), that targets formyl peptide receptor on neutrophils using a mice ear inflammation model is described. Acute inflammation was induced in mice by topical application of phorbol-12-myristate-13-acetate to left ears 24 hours before probe administration. Noninvasive NIRF imaging was longitudinally performed up to 24 hours following probe injection. The in vivo neutrophil-targeting specificity of the probe was characterized by a blocking study with preadministration of excess nonfluorescent peptide cFlFlF-PEG and by an imaging study with a scrambled peptide probe cLFFFL-PEG-Cy7. NIRF imaging of mice injected with cinnamoyl-L-F-F-F-L-PEG-cyanine7 (cFlFlF-PEG-Cy7) revealed that the fluorescence intensity for inflamed left ears was approximately fourfold higher than that of control right ears at 24 hours postinjection. In comparison, the ratios acquired with the scrambled probe and from the blocking study were 1.5- and 2-fold at 24 hours postinjection, respectively. Moreover, a microscopic immunohistologic study confirmed that the NIRF signal of cFlFlF-PEG-Cy7 was associated with activated neutrophils in the inflammatory tissue. With this probe, in vivo neutrophil chemotaxis could be correlatively imaged macroscopically in live animals and microscopically at tissue and cellular levels.