Human Resistin Is a Systemic Immune-Derived Proinflammatory Cytokine Targeting both Leukocytes and Adipocytes

The characteristics of human resistin (RETN) are unclear and controversial despite intensive adipose-focused research. Its transcriptional and functional similarity with the murine myeloid-specific and CCAAT/enhancer binding protein epsilon (Cebpe)-dependent gene, resistin-like gamma (Retnlg), is unexplored. We examined the human CEBPE-regulatory pathway by unbiased reference and custom gene expression assays. Real-time RT-PCR analysis demonstrated lack of both the transcriptional factor CEBPE and RETN expression in adipose and muscle cells. In contrast, primary myelocytic samples revealed a concerted CEBPE-RETN transcription that was significantly elevated in inflammatory synoviocytes relative to intact peripheral blood mononuclear cells (PBMC). Mouse Cebpe and Retnlg were predictably expressed in macrophages, whereas Retn was abundant in adipocytes. Quite the opposite, a low and inconsistent RETN transcription was seen in some human white adipose tissue (WAT) biopsies without any relationship to body mass index, insulin sensitivity, or fat depot. However, in these cases, RETN was co-detected with CEBPE and the leukocyte-specific marker, EMR1, indicating the presence of inflammatory cells and their possible resistin-mediated effect on adipocytes. Indeed, addition of human resistin to WAT in culture induced, like in PBMC, the inflammatory cytokines IL6, IL8 and TNF. Importantly, the expression of the adipose-specific markers CEBPA, FABP4 and SLC2A4 was unchanged, while the expected inhibitory effect was seen with TNF. Both cytokines increased the mRNA level of CCL2 and MMP3, which may further promote inflammation in WAT. Thus, the myeloid-restricted nature of CEBPE precludes the expression of RETN in human adipocytes which, however, are targeted by this innate immune-derived proinflammatory cytokine

Phreatomagmatic explosions of rhyolitic magma: Experimental and field evidence

Experimental studies on explosive molten fuel-coolant interaction (MFCI) using basaltic melt compositions and water as the coolant have provided insight into the physical processes of basaltic and andesitic phreatomagmatic volcanism. Abundant field evidence indicates that rhyolitic and dacitic phreatomagmatism occurs in nature, but it has not been possible until now to generate laboratory MFCI explosions from the interaction between high-silica melts and water under laboratory conditions. The high viscosity of these melts apparently prevents formation of an effective hydrodynamic premix of melt and water, the documented precursor of experimental explosive MFCI caused by mafic melts. Our new experiments utilized samples from a rhyolitic tuff ring volcano in Mexico (Tepexitl). An experimental approach was developed, in which premixing conditions were generated by mechanical deformation of the melt, leading to brittle-type fragmentation at the melt-water interface. Physical measurements recorded during laboratory explosion provide quantitative evidence for rhyolitic explosive MFCI. Additionally, a comparison of experimentally produced particles with natural ones from Tepexitl deposits show nearly identical chemical/mineralogical composition, grain size, and grain morphology. Detailed textural analysis confirmed the presence of phreatomagmatically produced particles in both experimental and natural analog particles. The results from this series of experiments indicate that under natural conditions, stress-induced magma fracturing can lead to a critical magma-water-interface growths and trigger phreatomagmatic explosions of high-silica magma. The water source for these eruptions may include shallow aquifers, surface water bodies, strong precipitation, and intrusion into ice or wet, unconsolidated sediments

Ionospheric irregularities at Jupiter observed by JWST

Jupiter’s upper atmosphere is composed of a neutral thermosphere and charged ionosphere. In the latter, the dominant molecular ion H3+ emits in the near-infrared, allowing for the remote exploration of the physical properties of the upper atmosphere. However, the Jovian low-latitude ionosphere remains largely unexplored because H3+ emissions from this region are faint and spectrally entangled with bright neutral species, such as CH4. Here, we present James Webb Space Telescope H3+ observations of Jupiter’s low-latitude ionosphere in the region of the Great Red Spot, showing unexpected small-scale intensity features such as arcs, bands and spots. Our observations may imply that the low-latitude ionosphere of Jupiter is strongly coupled to the lower atmosphere via gravity waves that superimpose to produce this complex and intricate morphology.</p