Inhibition of Progenitor Dendritic Cell Maturation by Plasma from Patients with Peripartum Cardiomyopathy: Role in Pregnancy-associated Heart Disease

Dendritic cells (DCs) play dual roles in innate and adaptive immunity based on their functional maturity, and both innate and adaptive immune responses have been implicated in myocardial tissue remodeling associated with cardiomyopathies. Peripartum cardiomyopathy (PPCM) is a rare disorder which affects women within one month antepartum to five months postpartum. A high occurrence of PPCM in central Haiti (1 in 300 live births) provided the unique opportunity to study the relationship of immune activation and DC maturation to the etiology of this disorder. Plasma samples from two groups (n = 12) of age- and parity-matched Haitian women with or without evidence of PPCM were tested for levels of biomarkers of cardiac tissue remodeling and immune activation. Significantly elevated levels of GM-CSF, endothelin-1, proBNP and CRP and decreased levels of TGF- were measured in PPCM subjects relative to controls. Yet despite these findings, in vitro maturation of normal human cord blood derived progenitor dendritic cells (CBDCs) was significantly reduced (p < 0.001) in the presence of plasma from PPCM patients relative to plasma from post-partum control subjects as determined by expression of CD80, CD86, CD83, CCR7, MHC class II and the ability of these matured CBDCs to induce allo-responses in PBMCs. These results represent the first findings linking inhibition of DC maturation to the dysregulation of normal physiologic cardiac tissue remodeling during pregnancy and the pathogenesis of PPCM

Risk Prediction for Clonal Cytopenia: Multicenter Real-World Evidence.

Clonal cytopenia of undetermined significance (CCUS) represents a distinct disease entity characterized by myeloid-related somatic mutations with a variant allele fraction of ≥2% in individuals with unexplained cytopenia(s) but without a myeloid neoplasm (MN). Notably, CCUS carries a risk of progressing to MN, particularly in cases featuring high-risk mutations. Understanding CCUS requires dedicated studies to elucidate its risk factors and natural history. Our analysis of 357 CCUS patients investigated the interplay between clonality, cytopenia, and prognosis. Multivariate analysis identified 3 key adverse prognostic factors: the presence of splicing mutation(s) (score = 2 points), platelet count &lt;100×109/L (score = 2.5), and ≥2 mutations (score = 3). Variable scores were based on the coefficients from the Cox proportional hazards model. This led to the development of the Clonal Cytopenia Risk Score (CCRS), which stratified patients into low- (score &lt;2.5 points), intermediate- (score 2.5-&lt;5), and high-risk (score ≥5) groups. The CCRS effectively predicted 2-year cumulative incidence of MN for low- (6.4%), intermediate- (14.1%), and high- (37.2%) risk groups, respectively, by Gray's test (P &lt;.0001). We further validated the CCRS by applying it to an independent CCUS cohort of 104 patients, demonstrating a c-index of 0.64 (P =.005) in stratifying the cumulative incidence of MN. Our study underscores the importance of integrating clinical and molecular data to assess the risk of CCUS progression, making the CCRS a valuable tool that is practical and easily calculable. These findings are clinically relevant, shaping the management strategies for CCUS and informing future clinical trial designs

LKB1 protein expression in human breast cancer

Peutz-Jeghers syndrome is caused by germline mutations in the LKB1/STK11 gene. Peutz-Jeghers syndrome is associated with an increased risk of developing intestinal and extraintestinal cancers, including pancreatic, lung, and breast carcinomas. LKB1 gene inactivation has recently been demonstrated in a subset of sporadic pancreatic and lung carcinomas. The role of the LKB1 gene in sporadic breast carcinomas remains unclear, though recent studies suggest inactivation only within papillary carcinomas. Using a commercially available polyclonal antibody that has been shown to mirror LKB1 genetic status in gastrointestinal and pulmonary carcinomas, the authors performed IHC on a large series of breast cancers using tissue microarrays (TMAs). All abnormal TMA results were confirmed using whole sections; specifically, whole sections from the donor blocks of lesions demonstrating diminished or absent LKB1 protein expression on TMA were evaluated to compare labeling of the lesion with that of the surrounding normal breast. In all cases, normal breast epithelium demonstrated strong cytoplasmic labeling (providing an internal positive control), whereas the stroma was nonreactive. Luminal cells typically labeled more strongly than myoepithelial cells. Among 70 invasive ductal carcinomas, 3 (4.3%) showed complete loss of LKB1 labeling, whereas 6 others (8.6%) showed diminished labeling. Of the eight intraductal carcinoma lesions adjacent to these invasive carcinomas, one (12.5%) showed complete loss of LKB1 labeling and one other (12.5%) showed diminished labeling; these results were identical to those of the adjacent invasive carcinomas. One of 10 (10%) hematogenous metastases of mammary carcinoma showed loss of LKB1 labeling. Nine of the 10 invasive carcinomas and both of the ductal carcinoma in situ (DCIS) cases showing loss of or diminished LKB1 expression were of high grade. In contrast, all 13 pure nonpapillary DCIS lesions, all 5 invasive lobular carcinomas and 3 accompanying lobular carcinoma in situ lesions, all 7 papillary DCIS lesions, and all 3 papillomas evaluated showed intact LKB1 labeling. Therefore, although frequent methylation of the LKB1 gene has been reported in papillary carcinomas of the breast, the authors did not find loss of protein expression in these lesions. Instead, it was found that loss of LKB1 protein expression occurs in a subset of high-grade in situ and invasive mammary carcinomas. The authors found LKB1 gene methylation in several of these invasive carcinomas. Given recent Western blot results indicating that diminished LKB1 expression in breast carcinomas correlates with shorter relapse-free survival, LKB1 IHC merits evaluation as a potential prognostic marker for breast carcinoma

Constitutive Dimerization of the G-Protein Coupled Receptor, Neurotensin Receptor 1, Reconstituted into Phospholipid Bilayers

Neurotensin receptor 1 (NTS1), a Family A G-protein coupled receptor (GPCR), was expressed in Escherichia coli as a fusion with the fluorescent proteins eCFP or eYFP. A fluorophore-tagged receptor was used to study the multimerization of NTS1 in detergent solution and in brain polar lipid bilayers, using fluorescence resonance energy transfer (FRET). A detergent-solubilized receptor was unable to form FRET-competent complexes at concentrations of up to 200 nM, suggesting that the receptor is monomeric in this environment. When reconstituted into a model membrane system at low receptor density, the observed FRET was independent of agonist binding, suggesting constitutive multimer formation. In competition studies, decreased FRET in the presence of untagged NTS1 excludes the possibility of fluorescent protein-induced interactions. A simulation of the experimental data indicates that NTS1 exists predominantly as a homodimer, rather than as higher-order multimers. These observations suggest that, in common with several other Family A GPCRs, NTS1 forms a constitutive dimer in lipid bilayers, stabilized through receptor-receptor interactions in the absence of other cellular signaling components. Therefore, this work demonstrates that well-characterized model membrane systems are useful tools for the study of GPCR multimerization, allowing fine control over system composition and complexity, provided that rigorous control experiments are performed