Publications search

Lead exposure is an unresolved pediatric health risk and disproportionately affects children in lower-income neighborhoods. Residences with children younger than age 5 years are the focus of mitigation policies; however, studies have shown that older children between the ages of 5 and 12 years also are at risk of central nervous system effects. Whether historically contaminated neighborhoods present ongoing risk to older children also is of concern. This study compared the blood lead levels (BLLs) of older children from an historically contaminated urban neighborhood to those of demographically matched children from a nearby rural locale and predicted significantly higher BLLs in the urban children. The study included 222 children aged 5-12 years, 111 from the urban neighborhood and 111 from local rural townships, matched for age, sex, race/ethnicity, and family income. Blood lead, cadmium, and mercury were measured using inductively coupled plasma mass spectrometry. General linear models tested whether geographic location (urban vs. rural) predicted child heavy metal levels, controlling for sex and age. Only location predicted only child BLL (R-2=0.36); children living in the urban setting had significantly higher BLLs as compared with matched rural township children (F=125, df(220,2), p<0.001). Neighborhoods with a history of lead contamination can present current risk of lead exposure for older children between the ages of 5 and 12 years, as well as for infants and toddlers. More studies are needed to better characterize the risk of lead exposure to older children, particularly in lower-income neighborhoods with a history of lead contamination.

Targeting microRNAs recently shows significant therapeutic promise; however, such progress is underdeveloped in treatment of skeletal diseases with osteolysis, such as osteoporosis and rheumatoid arthritis (RA). Here, we identified miR-182 as a key osteoclastogenic regulator in bone homeostasis and diseases. Myeloid-specific deletion of miR-182 protects mice against excessive osteoclastogenesis and bone resorption in disease models of ovariectomy-induced osteoporosis and inflammatory arthritis. Pharmacological treatment of these diseases with miR-182 inhibitors completely suppresses pathologic bone erosion. Mechanistically, we identify protein kinase double-stranded RNA-dependent (PKR) as a new and essential miR-182 target that is a novel inhibitor of osteoclastogenesis via regulation of the endogenous interferon (IFN)-beta-mediated autocrine feedback loop. The expression levels of miR-182, PKR, and IFN-beta are altered in RA and are significantly correlated with the osteoclastogenic capacity of RA monocytes. Our findings reveal a previously unrecognized regulatory network mediated by miR-182-PKR-IFN-beta axis in osteoclastogenesis, and highlight the therapeutic implications of miR-182 inhibition in osteoprotection.

Using predictions based on environmental regularities is fundamental for adaptive behavior. While it is widely accepted that predictions across different stimulus attributes (e.g., time and content) facilitate sensory processing, it is unknown whether predictions across these attributes rely on the same neural mechanism. Here, to elucidate the neural mechanisms of predictions, we combine invasive electrophysiological recordings (human electrocorticography in 4 females and 2 males) with computational modeling while manipulating predictions about content ("what") and time ("when"). We found that "when" predictions increased evoked activity over motor and prefrontal regions both at early (similar to 180 ms) and late (430 - 450 ms) latencies. "What" predictability, however, increased evoked activity only over prefrontal areas late in time (420 - 460 ms). Beyond these dissociable influences, we found that "what" and "when" predictability interactively modulated the amplitude of early (165 ms) evoked responses in the superior temporal gyrus. We modeled the observed neural responses using biophysically realistic neural mass models, to better understand whether "what" and "when" predictions tap into similar or different neurophysiological mechanisms. Our modeling results suggest that "what" and "when" predictability rely on complementary neural processes: "what" predictions increased short-term plasticity in auditory areas, whereas "when" predictability increased synaptic gain in motor areas. Thus, content and temporal predictions engage complementary neural mechanisms in different regions, suggesting domain-specific prediction signaling along the cortical hierarchy. Encoding predictions through different mechanisms may endow the brain with the flexibility to efficiently signal different sources of predictions, weight them by their reliability, and allow for their encoding without mutual interference.

The polymerase-associated factor 1 (Paf1) complex is a general transcription elongation factor of RNA polymerase II, which is composed of five core subunits, Paf1, Ctr9, Cdc73, Leo1, and Rtf1, and functions as a diverse platform that broadly affects gene expression genome-wide. In this study, we solved the 2.9-A crystal structure of the core region composed of the Ctr9-Paf1-Cdc73 ternary complex from a thermophilic fungi, which provides a structural perspective of the molecular details of the organization and interactions involving the Paf1 subunits in the core complex. We find that Ctr9 is composed of 21 tetratricopeptide repeat (TPR) motifs that wrap three circular turns in a right-handed superhelical manner around the N-terminal region of an elongated singlepolypeptide-chain scaffold of Paf1. The Cdc73 fragment is positioned within the surface groove of Ctr9, where it contacts mainly with Ctr9 and minimally with Paf1. We also identified that the Paf1 complex preferentially binds single-strand-containing DNAs. Our work provides structural insights into the overall architecture of the Paf1 complex and paves the road forward for understanding the molecular mechanisms of the Paf1 complex in transcriptional regulation.

The cell wall of Gram-positive bacteria contains abundant surfaceexposed carbohydrate structures that are highly conserved. While these properties make surface carbohydrates ideal targets for immunotherapy, carbohydrates elicit a poor immune response that results primarily in low-affinity IgM antibodies. In a previous publication, we introduced the lysibody approach to address this shortcoming. Lysibodies are engineered molecules that combine a high-affinity carbohydrate-binding domain of bacterial or bacteriophage origin and an Fc effector portion of a human IgG antibody, thus directing effective immunity to conserved bacterial surface carbohydrates. Here, we describe the first example of a lysibody containing the binding domain from a bacteriocin, lysostaphin. We also describe the creation of five lysibodies with binding domains derived from phage lysins, directed against Staphylococcus aureus. The lysostaphin and LysK lysibodies showed the most promise and were further characterized. Both lysibodies bound a range of clinically important staphylococcal strains, fixed complement on the staphylococcal surface, and induced phagocytosis of S. aureus by macrophages and human neutrophils. The lysostaphin lysibody had superior in vitro activity compared to that of the LysK lysibody, as well as that of the previously characterized ClyS lysibody, and it effectively protected mice in a kidney abscess/bacteremia model. These results further demonstrate that the lysibody approach is a reproducible means of creating antibacterial antibodies that cannot be produced by conventional means. Lysibodies therefore are a promising solution for opsonic antibodies that may be used passively to both treat and prevent infection by drug-resistant pathogens.

Chronic inflammatory diseases are characterized by recurrent inflammatory attacks in the tissues mediated by autoreactive T cells. Identity and functional programming of CD8(+) T cells at the target site of inflammation still remain elusive. One key question is whether, in these antigen-rich environments, chronic stimulation leads to CD8(+) T cell exhaustion comparable to what is observed in infectious disease contexts. In the synovial fluid (SF) of juvenile idiopathic arthritis (JIA) patients, a model of chronic inflammation, an overrepresentation of PD-1(+)CD8(+) T cells was found. Gene expression profiling, gene set enrichment analysis, functional studies, and extracellular flux analysis identified PD-1(+)CD8(+ )T cells as metabolically active effectors, with no sign of exhaustion. Furthermore, PD-1(+)CD8(+) T cells were enriched for a tissue-resident memory (Trm) cell transcriptional profile and demonstrated increased clonal expansion compared with the PD-1(-) counterpart, suggesting antigen-driven expansion of locally adapted cells. Interestingly, this subset was also found increased in target tissues in other human chronic inflammatory diseases. These data indicate that local chronic inflammation drives the induction and expansion of CD8(+) T cells endowed with potential detrimental properties. Together, these findings lay the basis for investigation of PD-1-expressing CD8(+) T cell targeting strategies in human chronic inflammatory diseases.

Caspases are well known for their role as executioners of apoptosis. However, recent studies have revealed that these lethal enzymes also have important mitogenic functions. Caspases can promote proliferation through autonomous regulation of the cell cycle, as well as by induction of secreted signals, which have a profound impact in neighboring tissues. Here, I review the proliferative role of caspases during development and homeostasis, in addition to their key regenerative function during tissue repair upon injury. Furthermore, the emerging properties of apoptotic caspases as drivers of carcinogenesis are discussed, as well as their involvement in other diseases. Finally, I examine further effects of caspases regulating death and survival in a non-autonomous manner. (C) 2017 The Author. Published by Elsevier Ltd.

The in-depth understanding of skin resident memory CD8(+) T lymphocytes (T-RM) may help to uncover strategies for their manipulation during disease. We investigated isolated T-RM from healthy human skin, which expressed the residence marker CD69, and compared them to circulating CD8(+) T cell populations from the same donors. There were significantly increased proportions of CD8(+)CD45RA(-)CD27(-) T cells in the skin that expressed low levels of killer cell lectin-like receptor G1 (KLRG1), CD57, perforin and granzyme B. The CD8(+) T-RM in skin were therefore phenotypically distinct from circulating CD8(+)CD45RA(-)CD27(-) T cells that expressed high levels of all these molecules. Nevertheless, the activation of CD8(+) T-RM with T cell receptor (TCR)/CD28 or interleukin (IL)-2 or IL-15 in vitro induced the expression of granzyme B. Blocking signalling through the inhibitory receptor programmed cell death 1 (PD)-1 further boosted granzyme B expression. A unique feature of some CD8(+) T-RM cells was their ability to secrete high levels of tumour necrosis factor (TNF)- and IL-2, a cytokine combination that was not seen frequently in circulating CD8(+) T cells. The cutaneous CD8(+) T-RM are therefore diverse, and appear to be phenotypically and functionally distinct from circulating cells. Indeed, the surface receptors used to distinguish differentiation stages of blood T cells cannot be applied to T cells in the skin. Furthermore, the function of cutaneous T-RM appears to be stringently controlled by environmental signals in situ.