Lymphokine signal transduction

Temporal profiling of cytokines in passively expressed sweat for detection of infection using wearable device

This work presents the viability of passive eccrine sweat as a functional biofluid toward tracking the human body's inflammatory response. Cytokines are biomarkers that orchestrate the manifestation and progression of an infection/inflammatory event. Hence, noninvasive, real-time monitoring of cytokines can be pivotal in assessing the progression of infection/inflammatory event, which may be feasible through monitoring of host immune markers in eccrine sweat. This work is the first experimental proof demonstrating the ability to detect inflammation/infection such as fever, FLU directly from passively expressed sweat in human subjects using a wearable "SWEATSENSER" device. The developed SWEATSENSER device demonstrates stable, real-time monitoring of inflammatory cytokines in passive sweat. An accuracy of >90% and specificity >95% was achieved using SWEATSENSER for a panel of cytokines (interleukin-6, interleukin-8, interleukin-10, and tumor necrosis factor-α) over an analytical range of 0.2-200 pg mL-1. The SWEATSENSER demonstrated a correlation of Pearson's r > 0.98 for the study biomarkers in a cohort of 26 subjects when correlated with standard reference method. Comparable IL-8 levels (2-15 pg mL-1) between systemic circulation (serum) and eccrine sweat through clinical studies in a cohort of 15 subjects, and the ability to distinguish healthy and sick (infection) cohort using inflammatory cytokines in sweat provides pioneering evidence of the SWEATSENSER technology for noninvasive tracking of host immune response biomarkers. Such a wearable device can offer significant strides in improving prognosis and provide personalized therapeutic treatment for several inflammatory/infectious diseases.

IL1α and TNFα Induction of Monocyte Chemoattractant Protein-1 (MCP-1/JE) in Bone Marrow Stromal Cells: The Role of Protein Kinase C (PKC) and Protein Tyrosine Kinase (PTK) Activity

Chemotactic cytokines (chemokines) have been shown to influence myelopoiesis. Bone marrow stromal cell line +/+-1. LDA11 expresses MCP-1/JE chemokine upon stimulation with ILlα and TNFα. We have examined the role of PKC and PTK dependent protein phosphorylation in induction of MCP-1/JE by using PKC and PTK specific inhibitors. PKC inhibitors staurosporine and H-7, as well as PTK inhibitors herbimycin A and genistein suppressed MCP-1/JE expression (mRNA and protein) in a dose dependent manner. The suppression of MCP-1/JE by both classes of inhibitors was partially to completely reversible. While PKC only regulated gene expression posttranscriptionally (mRNA stability), transcription of MCP-l/JE gene by ILlα and TNFα depends both upon PKC and PTK activity, as demonstrated by nuclear run-on analyses. Furthermore, treatment of cells with IL1a and TNFα involved NF-kB mobilization. There was no effect of PKC inhibitors on NF-kB mobilization by either ILlα or TNFα. In contrast, mobilization of NF-kB was negatively affected by PTK inhibitors in a stimulus selective manner (e.g., herbimycin A and genistein inhibited IL1α and TNFα induced NF-kB mobilization, respectively). We conclude from these findings that while both PKC and PTK inhibitors suppress MCP-1/JE gene transcription, only PTK inhibitors do so by suppressing NF-kB activation.

IL-3 stimulated haemopoietic stem cell proliferation: evidence for G protein independent mitogenic signalling events

Interleukin-3 stimulates the survival and proliferation of the FDCP-Mix 1 multipotent stem cell line. We have investigated the possible involvement of a guanyl nucleotide regulatory (G) protein(s) in the IL-3 stimulated proliferative response. We report here that pertussis toxin (PT) can partially inhibit IL-3 stimulated DNA synthesis and that this inhibition is bypassed by TPA. The ADP-ribosylation of the PT substrate G protein in vivo is complete in 2 hours without concomitant inhibition of IL-3 stimulated hexose transport or Na+/H+ exchange. When loaded into FDCP-Mix 1 cells fluoroaluminate and GTP-gamma-S, which can directly activate G proteins, are not capable of mimicking the effects of IL-3. Evidence is also presented that IL-3 does not stimulate a membrane-bound high affinity GTPase activity in the FDCP-Mix 1 cell line. These data suggest that a PT substrate G protein(s) can influence the IL-3 signalling cascade in an indirect or permissive manner, but that the IL-3 receptor does not directly couple to a PT substrate G protein.

Cellular signalling events stimulated by myeloid haemopoietic growth factors

In haemopoietic cells, proliferation, commitment to development, lineage restriction and survival via suppression of apoptosis can all be controlled by haemopoietic growth factors. The mechanisms underlying the regulation of these events can now be studied since recombinant forms of most of these haemopoietic growth factors are now available. Recent advances in cell purification techniques and the development of multipotent cell lines (see Spangrude et al, 1988; Whetton, 1990; Heyworth et al, 1988, 1990a; Jones et al, 1990) have provided suitable cell populations on which to study the cellular signalling events associated with differentiation and lineage restriction. This process has started with the elucidation of the structure and expression of many of the myeloid growth factor receptors, which should now facilitate progress in the study of the signal transduction mechanisms these growth factors employ. Another important facet of these studies will be to determine whether a single growth factor with multiple target cell types, ranging from multipotent cells to postmitotic cells (e.g. neutrophils), employs distinct signalling mechanisms depending on the target cell in question. The cellular signalling events elicited by each of these growth factors and the ways in which they can regulate the transcriptional activation of genes associated with specific developmental events are going to be key areas of haemopoietic research in the next few years.