Arnold J. Stromberg

The Expression of MicroRNA miR-107 Decreases Early in Alzheimer's Disease and May Accelerate Disease Progression through Regulation of β-Site Amyloid Precursor Protein-Cleaving Enzyme 1

MicroRNAs (miRNAs) are small regulatory RNAs that participate in posttranscriptional gene regulation in a sequence-specific manner. However, little is understood about the role(s) of miRNAs in Alzheimers disease (AD). We used miRNA expression microarrays on RNA extracted from human brain tissue from the University of Kentucky Alzheimers Disease Center Brain Bank with near-optimal clinicopathological correlation. Cases were separated into four groups: elderly nondemented with negligible AD-type pathology, nondemented with incipient AD pathology, mild cognitive impairment (MCI) with moderate AD pathology, and AD. Among the AD-related miRNA expression changes, miR-107 was exceptional because miR-107 levels decreased significantly even in patients with the earliest stages of pathology. In situ hybridization with cross-comparison to neuropathology demonstrated that particular cerebral cortical laminas involved by AD pathology exhibit diminished neuronal miR-107 expression. Computational analysis predicted that the 3′-untranslated region (UTR) of β-site amyloid precursor protein-cleaving enzyme 1 (BACE1) mRNA is targeted multiply by miR-107. From the same RNA material analyzed on miRNA microarrays, mRNA expression profiling was performed using Affymetrix Exon Array microarrays on nondemented, MCI, and AD patients. BACE1 mRNA levels tended to increase as miR-107 levels decreased in the progression of AD. Cell culture reporter assays performed with a subset of the predicted miR-107 binding sites indicate the presence of at least one physiological miR-107 miRNA recognition sequence in the 3′-UTR of BACE1 mRNA. Together, the coordinated application of miRNA profiling, Affymetrix microarrays, new bioinformatics predictions, in situ hybridization, and biochemical validation indicate that miR-107 may be involved in accelerated disease progression through regulation of BACE1.

Glycerol-3-phosphate is a critical mobile inducer of systemic immunity in plants

Glycerol-3-phosphate (G3P) is an important metabolite that contributes to the growth and disease-related physiologies of prokaryotes, plants, animals and humans alike. Here we show that G3P serves as the inducer of an important form of broad-spectrum immunity in plants, termed systemic acquired resistance (SAR). SAR is induced upon primary infection and protects distal tissues from secondary infections. Genetic mutants defective in G3P biosynthesis cannot induce SAR but can be rescued when G3P is supplied exogenously. Radioactive tracer experiments show that a G3P derivative is translocated to distal tissues, and this requires the lipid transfer protein, DIR1. Conversely, G3P is required for the translocation of DIR1 to distal tissues, which occurs through the symplast. These observations, along with the fact that dir1 plants accumulate reduced levels of G3P in their petiole exudates, suggest that the cooperative interaction of DIR1 and G3P orchestrates the induction of SAR in plants.

Secretory antibodies in breast milk promote long-term intestinal homeostasis by regulating the gut microbiota and host gene expression

Significance An experimental system was developed in mice to study the long-term benefits of early exposure to secretory antibodies of the IgA class (SIgA) in breast milk. We found that breast milk-derived SIgA promoted intestinal epithelial barrier function in suckling neonates, preventing systemic infection by potential pathogens. Long-term benefits of early exposure to SIgA included maintenance of a healthy gut microbiota and regulation of gene expression in intestinal epithelial cells. These findings suggest that maternal antibodies provide benefits to the intestinal immune system of the breast-fed infant, which persist into adulthood. Maintenance of intestinal homeostasis requires a healthy relationship between the commensal gut microbiota and the host immune system. Breast milk supplies the first source of antigen-specific immune protection in the gastrointestinal tract of suckling mammals, in the form of secretory IgA (SIgA). SIgA is transported across glandular and mucosal epithelial cells into external secretions by the polymeric Ig receptor (pIgR). Here, a breeding scheme with polymeric Ig receptor-sufficient and -deficient mice was used to study the effects of breast milk-derived SIgA on development of the gut microbiota and host intestinal immunity. Early exposure to maternal SIgA prevented the translocation of aerobic bacteria from the neonatal gut into draining lymph nodes, including the opportunistic pathogen Ochrobactrum anthropi. By the age of weaning, mice that received maternal SIgA in breast milk had a significantly different gut microbiota from mice that did not receive SIgA, and these differences were magnified when the mice reached adulthood. Early exposure to SIgA in breast milk resulted in a pattern of intestinal epithelial cell gene expression in adult mice that differed from that of mice that were not exposed to passive SIgA, including genes associated with intestinal inflammatory diseases in humans. Maternal SIgA was also found to ameliorate colonic damage caused by the epithelial-disrupting agent dextran sulfate sodium. These findings reveal unique mechanisms through which SIgA in breast milk may promote lifelong intestinal homeostasis, and provide additional evidence for the benefits of breastfeeding.

Correlation between prognostic factors and increasing age in melanoma.

Background: Age of patients with melanoma varies directly with mortality and inversely with the presence of sentinel lymph node (SLN) metastasis. To gain further insight into this apparent paradox, we analyzed the relationship between age and other major prognostic factors.Methods: The Sunbelt Melanoma Trial is a prospective, randomized study with 79 institutions involving SLN biopsy for melanoma. Eligible patients were 18 to 70 years old with melanoma of ≥1.0-mm Breslow thickness and clinically N0 regional lymph nodes. SLNs were evaluated by serial histological sections and immunohistochemistry for S-100 protein.Results: A total of 3076 patients were enrolled in the study, with a median follow-up of 19 months. Five age groups were examined: 18 to 30, 31 to 40, 41 to 50, 51 to 60, and 61 to 70 years. Trends between age and several key prognostic factors was identified: as age group increased, so did Breslow thickness (analysis of variance; P < .001), the incidence of ulceration and regression, and the proportion of male patients (each variable: χ2, P < .001). The incidence of SLN metastasis, however, declined with increasing age (χ2; P < .001).Conclusions: As age increases, so does Breslow thickness, the incidence of ulceration and regression, and the proportion of male patients—all poor prognostic factors. However, the frequency of SLN metastasis declines with increasing age. It is not known whether this represents a decreased sensitivity (higher false-negative rate) of the SLN procedure in older patients or a different biological behavior (hematogenous spread) of melanomas in older patients.

Profiling Tumor-Associated Antibodies for Early Detection of Non-small Cell Lung Cancer

Background: A blood test for non-small cell lung cancer (NSCLC) may be a valuable tool for use in a comprehensive lung cancer screening strategy. Here we report the potential of autoantibody profiling to detect early-stage and occult NSCLC. Methods: T7-phage NSCLC cDNA libraries were screened with patient plasma to identify phage-expressed proteins recognized by tumor-associated antibodies. Two hundred twelve immunogenic phage-expressed proteins, identified from 4000 clones, were statistically ranked for their individual reactivity with 23 stage I cancer patient and 23 risk-matched control samples. All 46 samples were used as a training set to define a combination of markers that were best able to distinguish patient from control samples; this set of classifiers was then examined using leave-one-out cross-validation. Markers were then used to predict probability of disease in 102 samples from the Mayo Clinic CT Screening Trial (six prevalence cancer samples, 40 drawn 1 to 5 years before diagnosis, and 56 risk-matched controls). Results: Measurements of the five most predictive antibody markers in 46 cases and controls were combined in a logistic regression model that yielded area under the receiver operating characteristics curve of 0.99; leave-one-out validation achieved 91.3% sensitivity and 91.3% specificity. In testing this marker set with samples from the Mayo Clinic Lung Screening Trial, we correctly predicted six of six prevalence cancers, 32 of 40 cancers from samples drawn 1 to 5 years before radiographic detection on incidence screening, and 49 of 56 risk-matched controls. Conclusions: Antibody profiling may be a useful tool for early detection of NSCLC.

Global Identification of Targets of the Arabidopsis MADS Domain Protein AGAMOUS-Like15

AGAMOUS-Like15 (AGL15) is a MADS domain transcriptional regulator that promotes somatic embryogenesis by binding DNA and regulating gene expression. Chromatin immunoprecipitation (ChIP) analysis previously identified DNA fragments with which AGL15 associates in vivo, and a low-throughput approach revealed a role for AGL15 in gibberellic acid catabolism that is relevant to embryogenesis. However, higher throughput methods are needed to identify targets of AGL15. Here, we mapped AGL15 in vivo binding sites using a ChIP-chip approach and the Affymetrix tiling arrays for Arabidopsis thaliana and found that ∼2000 sites represented in three biological replicates of the experiment are annotated to nearby genes. These results were combined with high-throughput measurement of gene expression in response to AGL15 accumulation to discriminate responsive direct targets from those further downstream in the network. LEAFY COTYLEDON2, FUSCA3, and ABA INSENSITIVE3, which encode B3 domain transcription factors that are key regulators of embryogenesis, were identified and verified as direct target genes of AGL15. Genes identified as targets of the B3 genes are also targets of AGL15, and we found that INDOLEACETIC ACID-INDUCED PROTEIN30 is involved in promotion of somatic embryo development. The data presented here and elsewhere suggest that much cross-regulation occurs in gene regulatory networks underpinning embryogenesis.

Prospective Multi-Institutional Study of Reverse Transcriptase Polymerase Chain Reaction for Molecular Staging of Melanoma

PURPOSE To evaluate the prognostic significance of molecular staging using reverse transcriptase polymerase chain reaction (RT-PCR) in detecting occult melanoma cells in sentinel lymph nodes (SLNs) and circulating bloodstream. PATIENTS AND METHODS In this multicenter study, eligibility criteria included patient age 18 to 71 years, invasive melanoma > or = 1.0 mm Breslow thickness, and no clinical evidence of metastasis. SLN biopsy and wide excision of the primary tumor were performed. SLNs were examined by serial-section histopathology and S-100 immunohistochemistry. A portion of each SLN was frozen for RT-PCR. In addition, RT-PCR was performed on peripheral-blood mononuclear cells (PBMCs). RT-PCR analysis was performed using four markers: tyrosinase, MART1, MAGE3, and GP-100. Disease-free survival (DFS), distant-DFS (DDFS), and overall survival (OS) were analyzed. RESULTS A total of 1,446 patients with histologically negative SLNs underwent RT-PCR analysis. At a median follow-up of 30 months, there was no difference in DFS, DDFS, or OS between the RT-PCR-positive (n = 620) and RT-PCR-negative (n = 826) patients. Analysis of PBMC from 820 patients revealed significant differences in DFS and DDFS, but not OS, for patients with detection of more than one RT-PCR marker in peripheral blood. CONCLUSION In this large, prospective, multi-institutional study, RT-PCR analysis on SLNs and PBMCs provides no additional prognostic information beyond standard histopathologic analysis of SLNs. Detection of more than one marker in PBMC is associated with a worse prognosis. RT-PCR remains investigational and should not be used to direct adjuvant therapy at this time.

Perianal Crohn Disease: Predictors of Need for Permanent Diversion

Objective:Fissures, fistulas, abscesses, and anal canal stenosis are manifestations of perianal Crohn disease (CD). There are no known predictors of which patients will fail sphincter-sparing surgical therapy and ultimately require fecal diversion. Methods:Of 356 consecutive patients with CD, 24% (86) had perianal CD (age range, 14–83 years), and women were slightly more frequently affected. Clinical variables were examined for factors predictive of the need for permanent fecal diversion. Results:CD associated with perianal CD was limited to the small bowel and/or ileocolic area in 23% of patients; the remainder had colorectal CD. Eighty-six patients underwent 344 operations. Forty-two patients (49%) ultimately required permanent diversion; among them were 21 of 32 patients (66%) with anal stricture and 12 of 20women (60%) with rectovaginal fistula. Univariate analyses of clinical variables were performed with respect to need for permanent fecal diversion. Significant univariate predictors were the presence of colonic CD (P = 0.0045, odds ratio [OR] 5.4), avoidance of ileocolic resection (P = 0.0147, OR 0.4), and the presence of an anal stricture (P = 0.0165, OR 3.0). In multivariate logistic regression, the presence of colonic disease and anal canal stricture were predictors of permanent diversion. The OR associated with the risk of permanent diversion in the presence of colonic disease and in the absence of anal stricture was 10 (P = 0.0345). In the presence of both colonic disease and anal canal stenosis, the OR associated with permanent stoma was 33 (P = 0.0023). Conclusions:The management of perianal CD continues to be challenging. Roughly half of patients required permanent fecal diversion, which was even more frequently true for patients with colonic CD and anal stenosis. Recognizing these tendencies will assist both patients and surgeons in planning optimal treatment.

Gender-Related Differences in Outcome for Melanoma Patients

Objective:To better understand the factors associated with the well-established gender difference in survival for patients with melanoma. Summary Background Data:Gender is an important factor in patients with cutaneous melanoma. Male patients have a worse outcome when compared with females. The reasons for this difference are poorly understood. Methods:This prospective multi-institutional study included patients aged 18 to 70 years with melanomas ≥1.0 mm Breslow thickness. Wide excision and sentinel lymph node (SLN) biopsy was performed in all patients. Clinicopathologic factors, including gender, were assessed and correlated with disease-free survival (DFS), distant disease-free survival (DDFS), and overall survival (OS). Results:A total of 3324 patients were included in the covariate analyses; 1829 patients had follow-up data available and were included in the survival analyses. Median follow-up was 30 months. On univariate analysis, men (n = 1906) were more likely than women to be older than 60 years (P < 0.0001), have thicker melanomas (P < 0.0001), have primary tumor regression (P = 0.0054), ulceration (P < 0.0001), and axial primary tumor location (P < 0.0001). On multivariate analysis, age (P = 0.0002), thickness (P < 0.0001), ulceration (P = 0.015), and location (P < 0.0001) remained significant in the model. There was no difference in the rate of SLN metastasis between men and women (P = 0.37) on multivariate analysis. When factors affecting survival were considered, the prognosis was worse for men as validated by lower DFS (P = 0.0005), DDFS (P < 0.0001), and OS (P < 0.0001). Conclusions:Male gender is associated with a greater incidence of unfavorable primary tumor characteristics without an increased risk for nodal metastasis. Nonetheless, gender is an independent factor affecting survival.

Molecular basis of age-associated cytokine dysregulation in LPS-stimulated macrophages

Aged humans and rodents are susceptible to infection with Streptococcus pneumoniae bacteria as a result of an inability to make antibodies to capsular polysaccharides. This is partly a result of decreased production of proinflammatory cytokines and increased production of interleukin (IL)‐10 by macrophages (MΦ) from aged mice. To understand the molecular basis of cytokine dysregulation in aged mouse MΦ, a microarray analysis was performed on RNA from resting and lipopolysaccharide (LPS)‐stimulated MΦ from aged and control mice using the Affymetrix Mouse Genome 430 2.0 gene chip. Two‐way ANOVA analysis demonstrated that at an overall P < 0.01 level, 853 genes were regulated by LPS (169 in only the young, 184 in only the aged, and 500 in both). Expression analysis of systematic explorer revealed that immune response (proinflammatory chemokines, cytokines, and their receptors) and signal transduction genes were specifically reduced in aged mouse MΦ. Accordingly, expression of Il1 and Il6 was reduced, and Il10 was increased, confirming our previous results. There was also decreased expression of interferon‐γ. Genes in the Toll‐like receptor‐signaling pathway leading to nuclear factor‐κB activation were also down‐regulated but IL‐1 receptor‐associated kinase 3, a negative regulator of this pathway, was increased in aged mice. An increase in expression of the gene for p38 mitogen‐activated protein kinase (MAPK) was observed with a corresponding increase in protein expression and enzyme activity confirmed by Western blotting. Low doses of a p38 MAPK inhibitor (SB203580) enhanced proinflammatory cytokine production by MΦ and reduced IL‐10 levels, indicating that increased p38 MAPK activity has a role in cytokine dysregulation in the aged mouse MΦ.