Ubiquitin E3 Ligases in Lung Disease

Diseases of the lung form the one of the largest causes of death globally. Inflammatory diseases such as Acute Respiratory Distress Syndrome, and fibrosis such as interstitial lung disease, in particular have high mortality rates with limited therapy. Thus, there is an unmet public health need for new avenues of intervention. Inflammatory, fibrotic, and nutrient lung diseases are driven by cellular signaling pathways, leading to pathological cell responses. Effector lung cells naturally dampen these deleterious signaling pathways; dysfunction of these dampening mechanisms play causal roles in lung disease, notably through excessive destruction of critical signal transduction proteins. Modulation of signal transduction protein degradation may have therapeutic effect by controlling deleterious signaling. The ubiquitin-proteasome system is the major cellular mechanism controlling protein degradation. Ubiquitin E3 ligase proteins are a critical part of ubiquitination, specifically targeting substrates for degradation. Research shows the importance of protein degradation in lung disease, however the potential to identify and inhibit specific E3-ligase-substrate interactions remains unexplored. Through both candidate-based and unbiased high-throughput screening techniques, we probed the importance of E3 ligases in lung disease through their targeted degradation of signal transduction proteins, and the therapeutic potential of E3 ligase inhibition. We investigated three aspects of lung disease – 1) inflammation and innate immunity, 2) fibrosis and interstitial lung disease, and 3) regulation of nutrient sensing mechanisms. Here we report multiple E3 ligase-substrate axes, including those associated with fibrosis: FIEL1-PIAS4; KLHL42-PPP2R5e, with innate immunity: PPP1R11-TLR2, RNF113A-CXCR4, KIAA0317-SOCS2, RNFT2-IL3Ra, and with nutrient sensing: RNF186-SESN2. We observed that E3 ligases potently control inflammatory signaling through control of cytokine receptors and signal modulators during acute inflammation and bacterial infection. We uncovered that E3 ligases are significantly associated with fibrotic signaling in interstitial lung fibrosis, and can be targeted by small molecules. Finally, we detected new mechanisms of nutrient sensor control leading to manipulation of anabolism. These results show the criticality of ubiquitin e3 ligases in the biology of lung inflammation, fibrosis, and nutrient sensing. Further, these studies validate ubiquitin E3 ligases as potential targets for therapeutic intervention to provide new tools to combat lung diseases

Inter-decadal variation in diadromous and potamodromous fish assemblages in a near pristine tropical dryland river

Freshwater ecosystems are both incredibly biodiverse and highly threatened globally. Variation in environmental parameters including habitat and flow can substantially affect many ecological processes within riverine aquatic communities, but the ties between such parameters and ecology are neither well studied nor understood. In highly variable tropical dryland river systems, assessing such relationships requires data collection over inter-decadal time scales, which is not typically permitted on development schedules driven over short periods (including election and funding cycles). Here, we used seine net sampling data collected over an 18-year period in the tropical dryland Fitzroy River, Western Australia, to assess how environmental and temporal factors including habitat, seasonality, and inter-annual variation in wet season magnitude affect the community assemblage structure, recruitment, and growth of aquatic species in dryland rivers. Results demonstrated that macrohabitat (main channel vs floodplain creek) and the magnitude of wet season rains and resultant flooding both had a substantial influence on biotic communities, alongside seasonal and diel variation. The magnitude of wet season flooding (measured as river discharge volume) had the greatest impact on assemblage composition within floodplain creek habitats and was a significant driver of recruitment rates and growth of recruits and adults of several species examined. This study highlights key considerations for conserving dryland river systems and constituent biota. Specifically, these are maintaining (a) rhythmicity of flow within each year, (b) diversity of flow volume between years, and (c) a variety of habitat types including ephemeral, semi-permanent, and permanent shallow floodplain and deeper main channel pools, in order to support a diverse array of generalist and specialist diadromous and potamodromous fishes

Recruitment of a critically endangered sawfish into a riverine nursery depends on natural flow regimes

The freshwater sawfish (Pristis pristis) was recently listed as the most Evolutionarily Distinct and Globally Endangered (EDGE) animal. The Fitzroy River in the remote Kimberley region of north-western Australia represents a significant stronghold for the species, which uses the freshwater reaches of the river as a nursery. There is also mounting pressure to develop the water resources of the region for agriculture that may substantially affect life history dynamics of sawfish in this system. However, the relationship between hydrology and population dynamics of freshwater sawfish was unknown. We used standardized catch data collected over 17 years to determine how wet season volume influences recruitment of freshwater sawfish into their riverine nursery. Negligible recruitment occurred in years with few days of high flood levels (above 98th percentile of cease-to-flow stage height), and relatively high recruitment occurred in years with 14 or more days of high flood levels. This relationship is indicative of a distinct boom-or-bust cycle, whereby freshwater sawfish rely almost entirely on the few years with large wet season floods, and the brief periods of highest water levels within these years, to replenish juvenile populations in the Fitzroy River nursery. This has direct implications for sustainable water resource management for the Fitzroy River basin in order to preserve one of the last known intact nursery habitats for this globally threatened species

Relative sea-level rise around East Antarctica during Oligocene glaciation

During the middle and late Eocene (∼48-34 Myr ago), the Earth's climate cooled and an ice sheet built up on Antarctica. The stepwise expansion of ice on Antarcticainduced crustal deformation and gravitational perturbations around the continent. Close to the ice sheet, sea level rosedespite an overall reduction in the mass of the ocean caused by the transfer of water to the ice sheet. Here we identify the crustal response to ice-sheet growth by forcing a glacial-hydro isostatic adjustment model with an Antarctic ice-sheet model. We find that the shelf areas around East Antarctica first shoaled as upper mantle material upwelled and a peripheral forebulge developed. The inner shelf subsequently subsided as lithosphere flexure extended outwards from the ice-sheet margins. Consequently the coasts experienced a progressive relative sea-level rise. Our analysis of sediment cores from the vicinity of the Antarctic ice sheet are in agreement with the spatial patterns of relative sea-level change indicated by our simulations. Our results are consistent with the suggestion that near-field processes such as local sea-level change influence the equilibrium state obtained by an icesheet grounding line

Influence of management practice on the microbiota of a critically endangered species: A longitudinal study of kākāpō chick faeces and associated nest litter

Background: The critically endangered kākāpō is a flightless, nocturnal parrot endemic to Aotearoa New Zealand. Recent efforts to describe the gastrointestinal microbial community of this threatened herbivore revealed a low-diversity microbiota that is often dominated by Escherichia-Shigella bacteria. Given the importance of associated microbial communities to animal health, and increasing appreciation of their potential relevance to threatened species conservation, we sought to better understand the development of this unusual gut microbiota profile. To this end, we conducted a longitudinal analysis of faecal material collected from kākāpō chicks during the 2019 breeding season, in addition to associated nest litter material. Results: Using an experimental approach rarely seen in studies of threatened species microbiota, we evaluated the impact of a regular conservation practice on the developing kākāpō microbiota, namely the removal of faecal material from nests. Artificially removing chick faeces from nests had negligible impact on bacterial community diversity for either chicks or nests (p > 0.05). However, the gut microbiota did change significantly over time as chick age increased (p < 0.01), with an increasing relative abundance of Escherichia-Shigella coli over the study period and similar observations for the associated nest litter microbiota (p < 0.01). Supplementary feeding substantially altered gut bacterial diversity of kākāpō chicks (p < 0.01), characterised by a significant increase in Lactobacillus bacteria. Conclusions: Overall, chick age and hand rearing conditions had the most marked impact on faecal bacterial communities. Similarly, the surrounding nest litter microbiota changed significantly over time since a kākāpō chick was first placed in the nest, though we found no evidence that removal of faecal material influenced the bacterial communities of either litter or faecal samples. Taken together, these observations will inform ongoing conservation and management of this most enigmatic of bird species

Senolytic vaccination: a new mandate for cardiovascular health?

Senescent cell accumulation is increasingly associated with a number of age-related cardiovascular diseases. Now, a new manuscript in Nature Aging suggests that a novel vaccine-based strategy might provide a targeted method to eliminate the senescent cell population

The Human IL-22 Receptor Is Regulated through the Action of the Novel E3 Ligase Subunit FBXW12, Which Functions as an Epithelial Growth Suppressor

Interleukin- (IL-) 22 signaling is protective in animal models of pneumonia and bacteremia by Klebsiella pneumoniae and mediates tissue recovery from influenza and Staph aureus infection. We recently described processing of mouse lung epithelial IL-22 receptor (IL-22R) by ubiquitination on the intracellular C-terminal. To identify cellular factors that regulate human IL-22R, we screened receptor abundance while overexpressing constituents of the ubiquitin system and identify that IL-22R can be shuttled for degradation by multiple previously uncharacterized F-box protein E3 ligase subunits. We observe that in human cells IL-22R is destabilized by FBXW12. FBXW12 causes depletion of endogenous and plasmid-derived IL-22R in lung epithelia, binds the E3 ligase constituent Skp-1, and facilitates ubiquitination of IL-22R in vitro. FBXW12 knockdown with shRNA increases IL-22R abundance and STAT3 phosphorylation in response to IL-22 cytokine treatment. FBXW12 shRNA increases human epithelial cell growth and cell cycle progression with enhanced constitutive activity of map kinases JNK and ERK. These findings indicate that the heretofore-undescribed protein FBXW12 functions as an E3 ligase constituent to ubiquitinate and degrade IL-22R and that therapeutic FBXW12 inhibition may enhance IL-22 signaling and bolster mucosal host defense and infection containment

Novel PDE4 inhibitors derived from Chinese medicine forsythia.

Cyclic adenosine monophosphate (cAMP) is a crucial intracellular second messenger molecule that converts extracellular molecules to intracellular signal transduction pathways generating cell- and stimulus-specific effects. Importantly, specific phosphodiesterase (PDE) subtypes control the amplitude and duration of cAMP-induced physiological processes and are therefore a prominent pharmacological target currently used in a variety of fields. Here we tested the extracts from traditional Chinese medicine, Forsythia suspense seeds, which have been used for more than 2000 years to relieve respiratory symptoms. Using structural-functional analysis we found its major lignin, Forsynthin, acted as an immunosuppressant by inhibiting PDE4 in inflammatory and immune cell. Moreover, several novel, selective small molecule derivatives of Forsythin were tested in vitro and in murine models of viral and bacterial pneumonia, sepsis and cytokine-driven systemic inflammation. Thus, pharmacological targeting of PDE4 may be a promising strategy for immune-related disorders characterized by amplified host inflammatory response