Neutrophils and other amoeboid cells chemotax by steering their front ends towards chemoattractant. Although Ras, Rac, Cdc42 and RhoA small GTPases all regulate chemotaxis, it has been unclear how ...they spatiotemporally control polarization and steering. Using fluorescence biosensors in neutrophil-like PLB-985 cells and photorelease of chemoattractant, we show that local Cdc42 signals, but not those of Rac, RhoA or Ras, precede cell turning during chemotaxis. Furthermore, pre-existing local Cdc42 signals in morphologically unpolarized cells predict the future direction of movement on uniform stimulation. Moreover, inhibition of actin polymerization uncovers recurring local Cdc42 activity pulses, suggesting that Cdc42 has the excitable characteristic of the compass activity proposed in models of chemotaxis. Globally, Cdc42 antagonizes RhoA, and maintains a steep spatial activity gradient during migration, whereas Ras and Rac form shallow gradients. Thus, chemotactic steering and de novo polarization are both directed by locally excitable Cdc42 signals.
For understanding cells functionalities and their communications, there is a need for highly sensitive cell analysis platforms capable of assessing non-specific chemicals on the surface and in the ...vicinity of cells. We report a microfluidic system integrating dielectrophoresis and surface enhanced Raman scattering (SERS) for the trapping and real time monitoring of cell functions in isolated and grouped cell clusters. Yeast cells are coated with silver nanoparticles to enable highly sensitive SERS analysis. The SERS responses of cells are examined under various conditions: live vs. dead and isolated vs. grouped. This work illustrates the feasibility of the system for in situ cell monitoring and analysis of secreted chemicals during their growth, metabolism, proliferation and apoptosis.
•Yeast cells are coated with Raman enhancing silver nanoparticles.•Dielectrophoresis is used to trap cells in configurable patterns for Raman analysis.•Raman signatures of dead and live yeast compared using principal component analysis.•Raman signatures from isolated cells are compared to that from cells in groups.•Principal component analysis identified glycine as a possible proliferation marker.
Human neutrophils are central players in innate immunity, a major component of inflammatory responses, and a leading model for cell motility and chemotaxis. However, primary neutrophils are ...short-lived, limiting their experimental usefulness in the laboratory. Thus, human myeloid cell lines have been characterized for their ability to undergo neutrophil-like differentiation in vitro. The HL-60 cell line and its PLB-985 sub-line are commonly used to model human neutrophil behavior, but how closely gene expression in differentiated cells resembles that of primary neutrophils has remained unclear.
In this study, we compared the effectiveness of differentiation protocols and used RNA sequencing (RNA-seq) to compare the transcriptomes of HL-60 and PLB-985 cells with published data for human and mouse primary neutrophils. Among commonly used differentiation protocols for neutrophil-like cell lines, addition of dimethyl sulfoxide (DMSO) gave the best combination of cell viability and expression of markers for differentiation. However, combining DMSO with the serum-free-supplement Nutridoma resulted in increased chemotactic response, phagocytic activity, oxidative burst and cell surface expression of the neutrophil markers FPR1 and CD11b without a cost in viability. RNA-seq analysis of HL-60 and PLB-985 cells before and after differentiation showed that differentiation broadly increases the similarity in gene expression between the cell lines and primary neutrophils. Furthermore, the gene expression pattern of the differentiated cell lines correlated slightly better with that of human neutrophils than the mouse neutrophil pattern did. Finally, we created a publicly available gene expression database that is searchable by gene name and protein domain content, where users can compare gene expression in HL-60, PLB-985 and primary human and mouse neutrophils.
Our study verifies that a DMSO-based differentiation protocol for HL-60 and PLB-985 cell lines gives superior differentiation and cell viability relative to other common protocols, and indicates that addition of Nutridoma may be preferable for studies of chemotaxis, phagocytosis, or oxidative burst. Our neutrophil gene expression database will be a valuable tool to identify similarities and differences in gene expression between the cell lines and primary neutrophils, to compare expression levels for genes of interest, and to improve the design of tools for genetic perturbations.
Prostate cancer (PCa) is the most common type of cancer in men in the United States, which disproportionately affects African American descents. While metastasis is the most common cause of death ...among PCa patients, no specific markers have been assigned to severity and ethnic biasness of the disease. MicroRNAs represent a promising new class of biomarkers owing to their inherent stability and resilience. In the present study, we investigated potential miRNAs that can be used as biomarkers and/or therapeutic targets and can provide insight into the severity and ethnic biasness of PCa. PCR array was performed in FFPE PCa tissues (5 Caucasian American and 5 African American) and selected differentially expressed miRNAs were validated by qRT-PCR, in 40 (15 CA and 25 AA) paired PCa and adjacent normal tissues. Significantly deregulated miRNAs were also analyzed in urine samples to explore their potential as non-invasive biomarker for PCa. Out of 8 miRNAs selected for validation from PCR array data, miR-205 (p<0.0001), mir-214 (p<0.0001), miR-221(p<0.001) and miR-99b (p<0.0001) were significantly downregulated in PCa tissues. ROC curve shows that all four miRNAs successfully discriminated between PCa and adjacent normal tissues. MiR-99b showed significant down regulation (p<0.01) in AA PCa tissues as compared to CA PCa tissues and might be related to the aggressiveness associated with AA population. In urine, miR-205 (p<0.05) and miR-214 (p<0.05) were significantly downregulated in PCa patients and can discriminate PCa patients from healthy individuals with 89% sensitivity and 80% specificity. In conclusion, present study showed that miR-205 and miR-214 are downregulated in PCa and may serve as potential non-invasive molecular biomarker for PCa.
Communication between organelles is an important feature of all eukaryotic cells. To uncover components involved in mitochondria/endoplasmic reticulum (ER) junctions, we screened for mutants that ...could be complemented by a synthetic protein designed to artificially tether the two organelles. We identified the Mmm1/Mdm10/Mdm12/Mdm34 complex as a molecular tether between ER and mitochondria. The tethering complex was composed of proteins resident of both ER and mitochondria. With the use of genome-wide mapping of genetic interactions, we showed that the components of the tethering complex were functionally connected to phospholipid biosynthesis and calcium-signaling genes. In mutant cells, phospholipid biosynthesis was impaired. The tethering complex localized to discrete foci, suggesting that discrete sites of close apposition between ER and mitochondria facilitate interorganelle calcium and phospholipid exchange.
Patients hospitalized for acute heart failure experience poor health status, including a high burden of symptoms and physical limitations, and poor quality of life. SGLT2 (sodium-glucose ...cotransporter 2) inhibitors improve health status in chronic heart failure, but their effect on these outcomes in acute heart failure is not well characterized. We investigated the effects of the SGLT2 inhibitor empagliflozin on symptoms, physical limitations, and quality of life, using the Kansas City Cardiomyopathy Questionnaire (KCCQ) in the EMPULSE trial (Empagliflozin in Patients Hospitalized With Acute Heart Failure Who Have Been Stabilized).
Patients hospitalized for acute heart failure were randomized to empagliflozin 10 mg daily or placebo for 90 days. The KCCQ was assessed at randomization and 15, 30, and 90 days. The effects of empagliflozin on the primary end point of clinical benefit (hierarchical composite of all-cause death, heart failure events, and a 5-point or greater difference in KCCQ Total Symptom Score TSS change from baseline to 90 days) were examined post hoc across the tertiles of baseline KCCQ-TSS. In prespecified analyses, changes (randomization to day 90) in KCCQ domains, including TSS, physical limitations, quality of life, clinical summary, and overall summary scores were evaluated using a repeated measures model.
In total, 530 patients were randomized (265 each arm). Baseline KCCQ-TSS was low overall (mean SD, 40.8 24.0 points). Empagliflozin-treated patients experienced greater clinical benefit across the range of KCCQ-TSS, with no treatment effect heterogeneity (win ratio 95% CIs from lowest to highest tertile: 1.49 1.01-2.20, 1.37 0.94-1.99, and 1.48 1.00-2.20, respectively;
for interaction=0.94). Beneficial effects of empagliflozin on health status were observed as early as 15 days and persisted through 90 days, at which point empagliflozin-treated patients experienced a greater improvement in KCCQ TSS, physical limitations, quality of life, clinical summary, and overall summary (placebo-adjusted mean differences 95% CI: 4.45 95% CI, 0.32-8.59,
=0.03; 4.80 95% CI, 0.00-9.61,
=0.05; 4.66 95% CI, 0.32-9.01,
=0.04; 4.85 95% CI, 0.77-8.92,
=0.02; and 4.40 points 95% CI, 0.33-8.48,
=0.03, respectively).
Initiation of empagliflozin in patients hospitalized for acute heart failure produced clinical benefit regardless of the degree of symptomatic impairment at baseline, and improved symptoms, physical limitations, and quality of life, with benefits seen as early as 15 days and maintained through 90 days.
URL: https://www.
gov; Unique identifier: NCT0415775.
To date, cross-species comparisons of genetic interactomes have been restricted to small or functionally related gene sets, limiting our ability to infer evolutionary trends. To facilitate a more ...comprehensive analysis, we constructed a genome-scale epistasis map (E-MAP) for the fission yeast Schizosaccharomyces pombe, providing phenotypic signatures for ∼60% of the nonessential genome. Using these signatures, we generated a catalog of 297 functional modules, and we assigned function to 144 previously uncharacterized genes, including mRNA splicing and DNA damage checkpoint factors. Comparison with an integrated genetic interactome from the budding yeast Saccharomyces cerevisiae revealed a hierarchical model for the evolution of genetic interactions, with conservation highest within protein complexes, lower within biological processes, and lowest between distinct biological processes. Despite the large evolutionary distance and extensive rewiring of individual interactions, both networks retain conserved features and display similar levels of functional crosstalk between biological processes, suggesting general design principles of genetic interactomes.
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► Genetic interaction map in fission yeast covering 60% of the nonessential genome ► ∼300 functional modules identified, providing function for uncharacterized genes ► Individual interactions between genes in different processes are poorly conserved ► Overall levels of genetic crosstalk between pairs of processes are highly conserved
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