Refinement of the taxonomic structure of 16SrXI and 16SrXIV phytoplasmas of gramineous plants using multilocus sequence typing

Phytoplasmas that infect gramineous plants, including Napier grass stunt, sugarcane whiteleaf, sugarcane grassy shoot, and Bermuda grass whiteleaf, have been classified into two closely related groups, 16SrXI and 16SrXIV, based on the 16S ribosomal RNA (rRNA) gene. Subsequently, phytoplasmas associated with coconut and Areca palm in southern India and Sri Lanka have been added into the 16SrXI group. However, the 16S rRNA gene gives relatively poor resolution between these phytoplasmas. In this study, a new set of universal phytoplasma primers that amplify approximately 1 kb of the leucyl transfer RNA synthetase (leuS) gene have been validated on a broad range of phytoplasma taxonomic groups. These have been used along with partial sequences of the secA gene to clarify the taxonomic classification of 16SrXI and 16SrXIV phytoplasmas. Based on this data, the sugarcane whiteleaf and grassy shoot phytoplasmas appear to be the same phytoplasma. The Napier grass stunt phytoplasma forms a distinct group from the Bermuda grass whiteleaf and sugarcane phytoplasmas, suggesting that Napier grass stunt should be in its own ‘Candidatus Phytoplasma sp.’. The phytoplasmas associated with coconut and arecanut in southern India and Sri Lanka, which are in the same 16SrXI group, appear in different groups based on secA analysis

Characterisation of Immune and Neuroinflammatory Changes Associated with Chemotherapy-Induced Peripheral Neuropathy

Chemotherapy-induced peripheral neuropathy (CIPN) and associated neuropathic pain is a debilitating adverse effect of cancer treatment. Current understanding of the mechanisms underpinning CIPN is limited and there are no effective treatment strategies. In this study, we treated male C57BL/6J mice with 4 cycles of either Paclitaxel (PTX) or Oxaliplatin (OXA) over a week and tested pain hypersensitivity and changes in peripheral immune responses and neuroinflammation on days 7 and 13 post 1st injection. We found that both PTX and OXA caused significant mechanical allodynia. In the periphery, PTX and OXA significantly increased circulating CD4+ and CD8+ T-cell populations. OXA caused a significant increase in the percentage of interleukin-4+ lymphocytes in the spleen and significant down-regulation of regulatory T (T-reg) cells in the inguinal lymph nodes. However, conditional depletion of T-reg cells in OXA-treated transgenic DEREG mice had no additional effect on pain sensitivity. Furthermore, there was no leukocyte infiltration into the nervous system of OXA- or PTX-treated mice. In the peripheral nervous system, PTX induced expression of the neuronal injury marker activating transcription factor-3 in IB4+ and NF200+ sensory neurons as well as an increase in the chemokines CCL2 and CCL3 in the lumbar dorsal root ganglion. In the central nervous system, PTX induced significant astrocyte activation in the spinal cord dorsal horn, and both PTX and OXA caused reduction of P2ry12+ homeostatic microglia, with no measurable changes in IBA-1+ microglia/macrophages in the dorsal and ventral horns. We also found that PTX induced up-regulation of several inflammatory cytokines and chemokines (TNF-α, IFN-γ, CCL11, CCL4, CCL3, IL-12p70 and GM-CSF) in the spinal cord. Overall, these findings suggest that PTX and OXA cause distinct pathological changes in the periphery and nervous system, which may contribute to chemotherapy-induced neuropathic pain

Metastatic phenotype and immunosuppressive tumour microenvironment in pancreatic ductal adenocarcinoma: Key role of the urokinase plasminogen activator (PLAU)

BackgroundPrevious studies have revealed the role of dysregulated urokinase plasminogen activator (encoded by PLAU) expression and activity in several pathways associated with cancer progression. However, systematic investigation into the association of PLAU expression with factors that modulate PDAC (pancreatic ductal adenocarcinoma) progression is lacking, such as those affecting stromal (pancreatic stellate cell, PSC)-cancer cell interactions, tumour immunity, PDAC subtypes and clinical outcomes from potential PLAU inhibition.MethodsThis study used an integrated bioinformatics approach to identify prognostic markers correlated with PLAU expression using different transcriptomics, proteomics, and clinical data sets. We then determined the association of dysregulated PLAU and correlated signatures with oncogenic pathways, metastatic phenotypes, stroma, immunosuppressive tumour microenvironment (TME) and clinical outcome. Finally, using an in vivo orthotopic model of pancreatic cancer, we confirmed the predicted effect of inhibiting PLAU on tumour growth and metastasis.ResultsOur analyses revealed that PLAU upregulation is not only associated with numerous other prognostic markers but also associated with the activation of various oncogenic signalling pathways, aggressive phenotypes relevant to PDAC growth and metastasis, such as proliferation, epithelial-mesenchymal transition (EMT), stemness, hypoxia, extracellular cell matrix (ECM) degradation, upregulation of stromal signatures, and immune suppression in the tumour microenvironment (TME). Moreover, the upregulation of PLAU was directly connected with signalling pathways known to mediate PSC-cancer cell interactions. Furthermore, PLAU upregulation was associated with the aggressive basal/squamous phenotype of PDAC and significantly reduced overall survival, indicating that this subset of patients may benefit from therapeutic interventions to inhibit PLAU activity. Our studies with a clinically relevant orthotopic pancreatic model showed that even short-term PLAU inhibition is sufficient to significantly halt tumour growth and, importantly, eliminate visible metastasis.ConclusionElevated PLAU correlates with increased aggressive phenotypes, stromal score, and immune suppression in PDAC. PLAU upregulation is also closely associated with the basal subtype type of PDAC; patients with this subtype are at high risk of mortality from the disease and may benefit from therapeutic targeting of PLAU

Role of Pancreatic Tumour-Derived Exosomes and Their Cargo in Pancreatic Cancer-Related Diabetes

One of the most common and deadly types of pancreatic cancer (PC) is pancreatic ductal adenocarcinoma (PDAC), with most patients succumbing to the disease within one year of diagnosis. Current detection strategies do not address asymptomatic PC; therefore, patients are diagnosed at an advanced stage when curative treatment is often no longer possible. In order to detect PC in asymptomatic patients earlier, the risk factors that could serve as reliable markers need to be examined. Diabetic mellitus (DM) is a significant risk factor for this malignancy and can be both a cause and consequence of PC. Typically, DM caused by PC is known as new-onset, pancreatogenic, pancreoprivic, or pancreatic cancer-related diabetes (PCRD). Although PCRD is quite distinct from type 2 DM (T2DM), there are currently no biomarkers that differentiate PCRD from T2DM. To identify such biomarkers, a better understanding of the mechanisms mediating PCRD is essential. To this end, there has been a growing research interest in recent years to elucidate the role of tumour-derived exosomes and their cargo in the pathogenesis of PCRD. Exosomes derived from tumours can be recognized for their specificity because they reflect the characteristics of their parent cells and are important in intercellular communication. Their cargo consists of proteins, lipids, and nucleic acids, which can be transferred to and alter the behaviour of recipient cells. This review provides a concise overview of current knowledge regarding tumour-derived exosomes and their cargo in PCRD and discusses the potential areas worthy of further study

Neuropathic Pain in Animal Models of Nervous System Autoimmune Diseases

Neuropathic pain is a frequent chronic presentation in autoimmune diseases of the nervous system, such as multiple sclerosis (MS) and Guillain-Barre syndrome (GBS), causing significant individual disablement and suffering. Animal models of experimental autoimmune encephalomyelitis (EAE) and experimental autoimmune neuritis (EAN) mimic many aspects of MS and GBS, respectively, and are well suited to study the pathophysiology of these autoimmune diseases. However, while much attention has been devoted to curative options, research into neuropathic pain mechanisms and relief has been somewhat lacking. Recent studies have demonstrated a variety of sensory abnormalities in different EAE and EAN models, which enable investigations of behavioural changes, underlying mechanisms, and potential pharmacotherapies for neuropathic pain associated with these diseases. This review examines the symptoms, mechanisms, and clinical therapeutic options in these conditions and highlights the value of EAE and EAN animal models for the study of neuropathic pain in MS and GBS

Australian scorpion Hormurus waigiensis venom fractions show broad bioactivity through modulation of bio-impedance and cytosolic calcium

Scorpion venoms are a rich source of bioactive molecules, but characterisation of toxin peptides affecting cytosolic Ca2+, central to cell signalling and cell death, is limited. We undertook a functional screening of the venom of the Australian scorpion Hormurus waigiensis to determine the breadth of Ca2+ mobilisation. A human embryonic kidney (HEK293) cell line stably expressing the genetically encoded Ca2+ reporter GCaMP5G and the rabbit type 1 ryanodine receptor (RyR1) was developed as a biosensor. Size-exclusion Fast Protein Liquid Chromatography separated the venom into 53 fractions, constituting 12 chromatographic peaks. Liquid chromatography mass spectroscopy identified 182 distinct molecules with 3 to 63 components per peak. The molecular weights varied from 258 Da—13.6 kDa, with 53% under 1 kDa. The majority of the venom chromatographic peaks (tested as six venom pools) were found to reversibly modulate cell monolayer bioimpedance, detected using the xCELLigence platform (ACEA Biosciences). Confocal Ca2+ imaging showed 9/14 peak samples, with molecules spanning the molecular size range, increased cytosolic Ca2+ mobilization. H. waigiensis venom Ca2+ activity was correlated with changes in bio-impedance, reflecting multi-modal toxin actions on cell physiology across the venom proteome

Role of Pancreatic Stellate Cell-Derived Exosomes in Pancreatic Cancer-Related Diabetes: A Novel Hypothesis

Pancreatic ductal adenocarcinoma (PDAC) is a devastating condition characterised by vague symptomatology and delayed diagnosis. About 30% of PDAC patients report a history of new onset diabetes, usually diagnosed within 3 years prior to the diagnosis of cancer. Thus, new onset diabetes, which is also known as pancreatic cancer-related diabetes (PCRD), could be a harbinger of PDAC. Diabetes is driven by progressive β cell loss/dysfunction and insulin resistance, two key features that are also found in PCRD. Experimental studies suggest that PDAC cell-derived exosomes carry factors that are detrimental to β cell function and insulin sensitivity. However, the role of stromal cells, particularly pancreatic stellate cells (PSCs), in the pathogenesis of PCRD is not known. PSCs are present around the earliest neoplastic lesions and around islets. Given that PSCs interact closely with cancer cells to drive cancer progression, it is possible that exosomal cargo from both cancer cells and PSCs plays a role in modulating β cell function and peripheral insulin resistance. Identification of such mediators may help elucidate the mechanisms of PCRD and aid early detection of PDAC. This paper discusses the concept of a novel role of PSCs in the pathogenesis of PCRD

Presentation_1_Noise-induced hearing loss vulnerability in type III intermediate filament peripherin gene knockout mice.pdf

In the post-natal mouse cochlea, type II spiral ganglion neurons (SGNs) innervating the electromotile outer hair cells (OHCs) of the ‘cochlear amplifier' selectively express the type III intermediate filament peripherin gene (Prph). Immunolabeling showed that Prph knockout (KO) mice exhibited disruption of this (outer spiral bundle) afferent innervation, while the radial fiber (type I SGN) innervation of the inner hair cells (~95% of the SGN population) was retained. Functionality of the medial olivocochlear (MOC) efferent innervation of the OHCs was confirmed in the PrphKO, based on suppression of distortion product otoacoustic emissions (DPOAEs) via direct electrical stimulation. However, “contralateral suppression” of the MOC reflex neural circuit, evident as a rapid reduction in cubic DPOAE when noise is presented to the opposite ear in wildtype mice, was substantially disrupted in the PrphKO. Auditory brainstem response (ABR) measurements demonstrated that hearing sensitivity (thresholds and growth-functions) were indistinguishable between wildtype and PrphKO mice. Despite this comparability in sound transduction and strength of the afferent signal to the central auditory pathways, high-intensity, broadband noise exposure (108 dB SPL, 1 h) produced permanent high frequency hearing loss (24–32 kHz) in PrphKO mice but not the wildtype mice, consistent with the attenuated contralateral suppression of the PrphKO. These data support the postulate that auditory neurons expressing Prph contribute to the sensory arm of the otoprotective MOC feedback circuit.</p