Description: Sepsis is an excessive inflammatory condition with a high mortality rate and limited prediction and therapeutic options. In this study, for the first time, to our knowledge, we found that downregulation and/or blockade of T cell Ig and mucin domain protein 3 (Tim-3), a negative immune regulator, correlated with severity of sepsis, suggesting that Tim-3 plays important roles in maintaining the homeostasis of sepsis in both humans and a mouse model. Blockade and/or downregulation of Tim-3 led to increased macrophage activation, which contributed to the systemic inflammatory response in sepsis, whereas Tim-3 overexpression in macrophages significantly suppressed TLR-mediated proinflammatory cytokine production, indicating that Tim-3 is a negative regulator of TLR-mediated immune responses. Cross-talk between the Tim-3 and TLR4 pathways makes TLR4 an important contributor to Tim-3–mediated negative regulation of the innate immune response. Tim-3 signaling inhibited LPS–TLR4–mediated NF-B activation by increasing PI3K–AKT phosphorylation and A20 activity. This negative regulatory role of Tim-3 reflects a new adaptive compensatory and protective mechanism in sepsis victims, a finding of potential importance for modulating innate responses in these patients.

Description: Cathelicidin antimicrobial peptides (CAMPs) represent a crucial component of the innate immune system in vertebrates. Although widely studied in mammals, little is known about the structure and function of fish CAMPs. Further to the previous findings, two more cathelicidin genes and multiple transcripts from rainbow trout were identified in the present study. Interestingly, we found that trout have evolved energy-saving forms of cathelicidins with the total deletion of the characteristic cathelin-like domain. Sequence analysis revealed that salmonid CAMPs have formed a special class of antimicrobial peptides in vertebrates with three distinctive hallmarks: the N terminus is intensified by positive charges, the central region consists of repetitive motifs based on RPGGGS, and the C terminus is lowly charged. Immunofluorescence localization of trout CAMPs demonstrated that these peptides expressed mainly at the mucosal layer of gut. Meanwhile, signals around sinusoids were also detected in head kidney. Moreover, the biological activities of trout CAMPs were proved to be mediated by the N terminus. Additionally, the repetitive motifs characteristically existing in Salmonidae increased the structural flexibilities of peptides and further increased the antibacterial and IL-8–stimulating activities. Unlike most α helical and cytotoxic mammalian CAMPs, trout CAMPs, mainly consisting of β-sheet and random coil, exhibited no cytotoxic activities. The distinctive structural features of trout CAMPs provide new insights into the understanding of the evolution of CAMPs in vertebrates. Moreover, the high bacterial membrane selectivity of trout CAMPs will help to design excellent peptide antibiotics.

Description: Continuous monitoring of variations in blood flow is vital in assessing the status of microvascular and macrovascular beds for a wide range of clinical and research scenarios. Although a variety of techniques exist, most require complete immobilization of the subject, thereby limiting their utility to hospital or clinical settings. Those that can be rendered in wearable formats suffer from limited accuracy, motion artifacts, and other shortcomings that follow from an inability to achieve intimate, noninvasive mechanical linkage of sensors with the surface of the skin. We introduce an ultrathin, soft, skin-conforming sensor technology that offers advanced capabilities in continuous and precise blood flow mapping. Systematic work establishes a set of experimental procedures and theoretical models for quantitative measurements and guidelines in design and operation. Experimental studies on human subjects, including validation with measurements performed using state-of-the-art clinical techniques, demonstrate sensitive and accurate assessment of both macrovascular and microvascular flow under a range of physiological conditions. Refined operational modes eliminate long-term drifts and reduce power consumption, thereby providing steps toward the use of this technology for continuous monitoring during daily activities.

Description: Single-molecule detection can reveal time trajectories and reaction pathways of individual intermediates/transition states in chemical reactions and biological processes, which is of fundamental importance to elucidate their intrinsic mechanisms. We present a reliable, label-free single-molecule approach that allows us to directly explore the dynamic process of basic chemical reactions at the single-event level by using stable graphene-molecule single-molecule junctions. These junctions are constructed by covalently connecting a single molecule with a 9-fluorenone center to nanogapped graphene electrodes. For the first time, real-time single-molecule electrical measurements unambiguously show reproducible large-amplitude two-level fluctuations that are highly dependent on solvent environments in a nucleophilic addition reaction of hydroxylamine to a carbonyl group. Both theoretical simulations and ensemble experiments prove that this observation originates from the reversible transition between the reactant and a new intermediate state within a time scale of a few microseconds. These investigations open up a new route that is able to be immediately applied to probe fast single-molecule physics or biophysics with high time resolution, making an important contribution to broad fields beyond reaction chemistry.

Description: Single-molecule electronic devices offer unique opportunities to investigate the properties of individual molecules that are not accessible in conventional ensemble experiments. However, these investigations remain challenging because they require (i) highly precise device fabrication to incorporate single molecules and (ii) sufficient time resolution to be able to make fast molecular dynamic measurements. We demonstrate a graphene-molecule single-molecule junction that is capable of probing the thermodynamic and kinetic parameters of a host-guest complex. By covalently integrating a conjugated molecular wire with a pendent crown ether into graphene point contacts, we can transduce the physical [2]pseudorotaxane (de)formation processes between the electron-rich crown ether and a dicationic guest into real-time electrical signals. The conductance of the single-molecule junction reveals two-level fluctuations that are highly dependent on temperature and solvent environments, affording a nondestructive means of quantitatively determining the binding and rate constants, as well as the activation energies, for host-guest complexes. The thermodynamic processes reveal the host-guest binding to be enthalpy-driven and are consistent with conventional 1 H nuclear magnetic resonance titration experiments. This electronic device opens up a new route to developing single-molecule dynamics investigations with microsecond resolution for a broad range of chemical and biochemical applications.

Description: Leveraging the quantum information-processing ability of superconducting circuits and long-distance distribution ability of optical photons promises the realization of complex and large-scale quantum networks. In such a scheme, a coherent and efficient quantum transducer between superconducting and photonic circuits is critical. However, this quantum transducer is still challenging because the use of intermediate excitations in current schemes introduces extra noise and limits bandwidth. We realize direct and coherent transduction between superconducting and photonic circuits based on the triple-resonance electro-optic principle, with integrated devices incorporating both superconducting and optical cavities on the same chip. Electromagnetically induced transparency is observed, indicating the coherent interaction between microwave and optical photons. Internal conversion efficiency of 25.9 ± 0.3% has been achieved, with 2.05 ± 0.04% total efficiency. Superconducting cavity electro-optics offers broad transduction bandwidth and high scalability and represents a significant step toward integrated hybrid quantum circuits and distributed quantum computation.

Description: Persistent activation of macrophages in lungs plays a critical role in the production of matrix metalloproteinases (MMPs) that contributes to the destruction of alveolar walls, a hallmark for pulmonary emphysema. Dysregulated TGF-β1 signaling has been an essential determinant in the elevation of MMPs during the development of emphysema. Nevertheless, the mechanism for this MMP-dependent pathogenesis has yet to be clearly investigated. Recently, we identified an important role for tyrosine phosphatase Src homology domain-containing protein tyrosine phosphatase 2 (Shp2) in regulating the activation of alveolar macrophages. Over a long-term observation period, mice with Shp2 deletion in macrophages ( LysMCre:Shp2 fl/fl ) develop spontaneous, progressive emphysema-like injury in the lungs, characterized by massive destruction of alveolar morphology, interstitial extracellular matrix degradation, and elevated levels of MMPs, particularly, significant increases of macrophage elastase (MMP12) in aged mice. Further analysis demonstrated that MMP12 suppression by TGF-β1 activation was apparently abrogated in LysMCre:Shp2 fl/fl mice, whereas the TGF-β1 concentration in the lungs was relatively the same. Mechanistically, we found that loss of Shp2 resulted in attenuated SMAD2/3 phosphorylation and nuclear translocation in response to TGF-β activation, thereby upregulating MMP12 expression in macrophages. Together, our findings define a novel physiological function of Shp2 in TGF-β1/MMP12-dependent emphysema, adding insights into potential etiologies for this chronic lung disorder.

Description: Human Ab-secreting cell (ASC) populations in circulation are not well studied. In addition to B-1 (CD20 + CD27 + CD38 lo/int CD43 + ) cell and conventional plasmablast (PB) (CD20-CD27 hi CD38 hi ) cell populations, in this study, we identified a novel B cell population termed 20 + 38 hi B cells (CD20 + CD27 hi CD38 hi ) that spontaneously secretes Ab. At steady-state, 20 + 38 hi B cells are distinct from PBs on the basis of CD20 expression, amount of Ab production, frequency of mutation, and diversity of BCR repertoire. However, cytokine treatment of 20 + 38 hi B cells induces loss of CD20 and acquisition of CD138, suggesting that 20 + 38 hi B cells are precursors to PBs or pre-PBs. We then evaluated similarities and differences among CD20 + CD27 + CD38 lo/int CD43 + B-1 cells, CD20 + CD27 hi CD38 hi 20 + 38 hi B cells, CD20 – CD27 hi CD38 hi PBs, and CD20 + CD27 + CD38 lo/int CD43 – memory B cells. We found that B-1 cells differ from 20 + 38 hi B cells and PBs in a number of ways, including Ag expression, morphological appearance, transcriptional profiling, Ab skewing, Ab repertoire, and secretory response to stimulation. In terms of gene expression, B-1 cells align more closely with memory B cells than with 20 + 38 hi B cells or PBs, but differ in that memory B cells do not express Ab secretion-related genes. We found that B-1 cell Abs use Vh4-34, which is often associated with autoreactivity, 3- to 6-fold more often than other B cell populations. Along with selective production of IgM anti–phosphoryl choline, these data suggest that human B-1 cells might be preferentially selected for autoreactivity/natural specificity. In summary, our results indicate that human healthy adult peripheral blood at steady-state consists of three distinct ASC populations.

Description: Strigolactones are key regulators of plant development and interaction with symbiotic fungi; however, quantitative tools for strigolactone signaling analysis are lacking. We introduce a genetically encoded hormone biosensor used to analyze strigolactone-mediated processes, including the study of the components involved in the hormone perception/signaling complex and the structural specificity and sensitivity of natural and synthetic strigolactones in Arabidopsis , providing quantitative insights into the stereoselectivity of strigolactone perception. Given the high specificity, sensitivity, dynamic range of activity, modular construction, ease of implementation, and wide applicability, the biosensor StrigoQuant will be useful in unraveling multiple levels of strigolactone metabolic and signaling networks.