Background and Aims
Hepatic sinusoidal cells are known actors in the fibrogenic response to injury. Activated hepatic stellate cells (HSCs), liver sinusoidal endothelial cells, and Kupffer cells are ...responsible for sinusoidal capillarization and perisinusoidal matrix deposition, impairing vascular exchange and heightening the risk of advanced fibrosis. While the overall pathogenesis is well understood, functional relations between cellular transitions during fibrogenesis are only beginning to be resolved. At single‐cell resolution, we here explored the heterogeneity of individual cell types and dissected their transitions and crosstalk during fibrogenesis.
Approach and Results
We applied single‐cell transcriptomics to map the heterogeneity of sinusoid‐associated cells in healthy and injured livers and reconstructed the single‐lineage HSC trajectory from pericyte to myofibroblast. Stratifying each sinusoidal cell population by activation state, we projected shifts in sinusoidal communication upon injury. Weighted gene correlation network analysis of the HSC trajectory led to the identification of core genes whose expression proved highly predictive of advanced fibrosis in patients with nonalcoholic steatohepatitis (NASH). Among the core members of the injury‐repressed gene module, we identified plasmalemma vesicle–associated protein (PLVAP) as a protein amply expressed by mouse and human HSCs. PLVAP expression was suppressed in activated HSCs upon injury and may hence define hitherto unknown roles for HSCs in the regulation of microcirculatory exchange and its breakdown in chronic liver disease.
Conclusions
Our study offers a single‐cell resolved account of drug‐induced injury of the mammalian liver and identifies key genes that may serve important roles in sinusoidal integrity and as markers of advanced fibrosis in human NASH.
Persistent, unresolved inflammation in adipose tissue is a major contributor to obesity-associated metabolic complications. However, the molecular links between lipid-overloaded adipocytes and ...inflammatory immune cells in obese adipose tissues remain elusive. Here we identified adipocyte-secreted microRNA-34a (miR-34a) as a key mediator through its paracrine actions on adipose-resident macrophages. The expression of miR-34a in adipose tissues was progressively increased with the development of dietary obesity. Adipose-selective or adipocyte-specific miR-34a-KO mice were resistant to obesity-induced glucose intolerance, insulin resistance, and systemic inflammation, and this was accompanied by a significant shift in polarization of adipose-resident macrophages from proinflammatory M1 to antiinflammatory M2 phenotype. Mechanistically, mature adipocyte-secreted exosomes transported miR-34a into macrophages, thereby suppressing M2 polarization by repressing the expression of Krüppel-like factor 4 (Klf4). The suppressive effects of miR-34a on M2 polarization and its stimulation of inflammatory responses were reversed by ectopic expression of Klf4 in both bone marrow-derived macrophages and adipose depots of obese mice. Furthermore, increased miR-34a expression in visceral fat of overweight/obese subjects correlated negatively with reduced Klf4 expression, but positively with the parameters of insulin resistance and metabolic inflammation. In summary, miR-34a was a key component of adipocyte-secreted exosomal vesicles that transmitted the signal of nutrient overload to the adipose-resident macrophages for exacerbation of obesity-induced systemic inflammation and metabolic dysregulation.
The prenatal origins of cancer Marshall, Glenn M; Carter, Daniel R; Cheung, Belamy B ...
Nature reviews. Cancer,
04/2014, Letnik:
14, Številka:
4
Journal Article
Recenzirano
Odprti dostop
The concept that some childhood malignancies arise from postnatally persistent embryonal cells has a long history. Recent research has strengthened the links between driver mutations and embryonal ...and early postnatal development. This evidence, coupled with much greater detail on the cell of origin and the initial steps in embryonal cancer initiation, has identified important therapeutic targets and provided renewed interest in strategies for the early detection and prevention of childhood cancer.
The function of neural circuits and networks can be controlled, in part, by modulating the synchrony of their components' activities. Network hypersynchrony and altered oscillatory rhythmic activity ...may contribute to cognitive abnormalities in Alzheimer disease (AD). In this condition, network activities that support cognition are altered decades before clinical disease onset, and these alterations predict future pathology and brain atrophy. Although the precise causes and pathophysiological consequences of these network alterations remain to be defined, interneuron dysfunction and network abnormalities have emerged as potential mechanisms of cognitive dysfunction in AD and related disorders. Here, we explore the concept that modulating these mechanisms may help to improve brain function in these conditions.
Accumulated evidence from experimental animal models suggests that neuronal loss within the dorsal horn is involved in the development and/or maintenance of peripheral neuropathic pain. However, to ...date, no study has specifically investigated whether such neuroanatomical changes also occur at this level in humans. Using brain imaging techniques, we sought to determine whether anatomical changes were present in the spinal trigeminal nucleus in subjects with chronic orofacial neuropathic pain. In 22 subjects with painful trigeminal neuropathy and 44 pain-free controls, voxel-based morphometry of T1-weighted anatomical images and diffusion tensor images were used to assess regional gray matter volume and microstructural changes within the brainstem. In addition, deterministic tractography was used to assess the integrity of ascending pain pathways. Orofacial neuropathic pain was associated with significant regional gray matter volume decreases, fractional anisotropy increases, and mean diffusivity decreases within the spinal trigeminal nucleus, specifically the subnucleus oralis. In addition, tractography revealed no significant differences in diffusivity properties in the root entry zone of the trigeminal nerve, the spinal trigeminal tract, or the ventral trigeminothalamic tracts in painful trigeminal neuropathy subjects compared with controls. These data reveal that chronic neuropathic pain in humans is associated with discrete alterations in the anatomy of the primary synapse. These neuroanatomical changes may be critical for the generation and/or maintenance of pathological pain.
Parkinson's disease (PD) and dementia with Lewy bodies (DLB) are among the human synucleinopathies, which show alpha‐synuclein immunoreactive neuronal and/or glial aggregations and progressive ...neuronal loss in selected brain regions (eg, substantia nigra, ventral tegmental area, pedunculopontine nucleus). Despite several studies about brainstem pathologies in PD and DLB, there is currently no detailed information available regarding the presence of alpha‐synuclein immunoreactive inclusions (i) in the cranial nerve, precerebellar, vestibular and oculomotor brainstem nuclei and (ii) in brainstem fiber tracts and oligodendroctyes. Therefore, we analyzed the inclusion pathologies in the brainstem nuclei (Lewy bodies, LB; Lewy neurites, LN; coiled bodies, CB) and fiber tracts (LN, CB) of PD and DLB patients. As reported in previous studies, LB and LN were most prevalent in the substantia nigra, ventral tegmental area, pedunculopontine and raphe nuclei, periaqueductal gray, locus coeruleus, parabrachial nuclei, reticular formation, prepositus hypoglossal, dorsal motor vagal and solitary nuclei. Additionally we were able to demonstrate LB and LN in all cranial nerve nuclei, premotor oculomotor, precerebellar and vestibular brainstem nuclei, as well as LN in all brainstem fiber tracts. CB were present in nearly all brainstem nuclei and brainstem fiber tracts containing LB and/or LN. These findings can contribute to a large variety of less well‐explained PD and DLB symptoms (eg, gait and postural instability, impaired balance and postural reflexes, falls, ingestive and oculomotor dysfunctions) and point to the occurrence of disturbances of intra‐axonal transport processes and transneuronal spread of the underlying pathological processes of PD and DLB along anatomical pathways.
Endocrine tumours of the pancreas Öberg, Kjell; Eriksson, Barbro
Baillière's best practice & research. Clinical gastroenterology,
10/2005, Letnik:
19, Številka:
5
Journal Article
Recenzirano
Endocrine pancreatic tumours (EPTs) are uncommon tumours occurring in approximately 1 in 100 000 of the population, representing 1–2% of all pancreatic neoplasms. Some of the tumours may be part of ...multiple endocrine neoplasia type one (MEN-1) syndrome or von Hippel–Lindau (vHL) disease. EPTs are classified as functioning or non-functioning tumours on the basis of their clinical manifestation. The biochemical diagnosis of EPT is based on hormones and amines released. Besides specific markers such as insulin, there are also general tumour markers such as chromogranin A, which is the most valuable marker and has been reported to be increased in plasma in 50–80% of patients with EPTs and correlates with tumour burden. The location of endocrine tumours of the pancreas includes different techniques, from endoscopic investigations to scintigraphy (e.g. somatostatin receptor scintigraphy) and positron emission tomography. The medical treatment of endocrine pancreatic tumours consists of chemotherapy, somatostatin analogues and α-interferon. None of these can cure a patient with malignant disease. In future, therapy will be custom-made and based on current knowledge of tumour biology and molecular genetics.
Objective:
A study was undertaken to examine the neuropathological substrates of cognitive dysfunction and dementia in Parkinson disease (PD).
Methods:
One hundred forty patients with a clinical ...diagnosis of PD and either normal cognition or onset of dementia 2 or more years after motor symptoms (PDD) were studied. Patients with a clinical diagnosis of dementia with Lewy bodies were excluded. Autopsy records of genetic data and semiquantitative scores for the burden of neurofibrillary tangles, senile plaques, Lewy bodies (LBs), and Lewy neurites (LNs) and other pathologies were used to develop a multivariate logistic regression model to determine the independent association of these variables with dementia. Correlates of comorbid Alzheimer disease (AD) were also examined.
Results:
Niney‐two PD patients developed dementia, and 48 remained cognitively normal. Severity of cortical LB (CLB)/LN pathology was positively associated with dementia (p < 0.001), with an odds ratio (OR) of 4.06 (95% confidence interval CI, 1.87–8.81), as was apolipoprotein E4 (APOE4) genotype (p = 0.018; OR, 4.19; 95% CI, 1.28–13.75). A total of 28.6% of all PD cases had sufficient pathology for comorbid AD, of whom 89.5% were demented. The neuropathological diagnosis of PDD+AD correlated with an older age of PD onset (p = 0.001; OR, 1.12; 95% CI, 1.04–1.21), higher CLB/LN burden (p = 0.037; OR, 2.48; 95% CI, 1.06–5.82), and cerebral amyloid angiopathy severity (p = 0.032; OR, 4.16; 95% CI, 1.13–15.30).
Interpretation:
CLB/LN pathology is the most significant correlate of dementia in PD. Additionally, APOE4 genotype may independently influence the risk of dementia in PD. AD pathology was abundant in a subset of patients, and may modify the clinical phenotype. Thus, therapies that target α‐synuclein, tau, or amyloid β could potentially improve cognitive performance in PD. ANN NEUROL 2012;72:587–598
Understanding the origin of myofibroblasts in kidney is of great interest because these cells are responsible for scar formation in fibrotic kidney disease. Recent studies suggest epithelial cells ...are an important source of myofibroblasts through a process described as the epithelial-to-mesenchymal transition; however, confirmatory studies in vivo are lacking. To quantitatively assess the contribution of renal epithelial cells to myofibroblasts, we used Cre/Lox techniques to genetically label and fate map renal epithelia in models of kidney fibrosis. Genetically labeled primary proximal epithelial cells cultured in vitro from these mice readily induce markers of myofibroblasts after transforming growth factor β1 treatment. However, using either red fluorescent protein or β-galactosidase as fate markers, we found no evidence that epithelial cells migrate outside of the tubular basement membrane and differentiate into interstitial myofibroblasts in vivo . Thus, although renal epithelial cells can acquire mesenchymal markers in vitro , they do not directly contribute to interstitial myofibroblast cells in vivo . Lineage analysis shows that during nephrogenesis, FoxD1-positive(+ ) mesenchymal cells give rise to adult CD73+ , platelet derived growth factor receptor β+ , smooth muscle actin-negative interstitial pericytes, and these FoxD1-derivative interstitial cells expand and differentiate into smooth muscle actin+ myofibroblasts during fibrosis, accounting for a large majority of myofibroblasts. These data indicate that therapeutic strategies directly targeting pericyte differentiation in vivo may productively impact fibrotic kidney disease.
Background The role of pancreatic cyst fluid DNA analysis in evaluating pancreatic cysts remains unclear. Objective Our purpose was to evaluate the utility of a detailed DNA analysis of pancreatic ...cyst fluid to diagnose mucinous and malignant cysts. Design Prospective, multicenter study. Patients Patients with pancreatic cysts presenting for EUS evaluation. Intervention EUS-guided pancreatic cyst aspirates cytology evaluation, carcinoembryonic antigen (CEA) level determination, and a detailed DNA analysis; incorporating DNA quantification, k- ras mutation and multiple allelic loss analysis, mutational amplitude, and sequence determination. Main Outcome Measurements Cyst fluid analysis compared with surgical pathologic or malignant cytologic examination. Results The study cohort consisted of 113 patients with 40 malignant, 48 premalignant, and 25 benign cysts. Cyst fluid k- ras mutation was helpful in the diagnosis of mucinous cysts (odds ratio 20.9, specificity 96%), whereas receiver-operator characteristic curve analysis indicated optimal cutoff points for allelic loss amplitude (area under the curve AUC 0.79; optimal value > 65%) and CEA (AUC 0.74; optimal value >148 ng/mL). Components of DNA analysis detecting malignant cysts included allelic loss amplitude over 82% (AUC 0.9) and high DNA amount (optical density ratio >10, AUC 0.79). The criteria of a high amplitude k- ras mutation followed by allelic loss showed maximum specificity (96%) for malignancy. All malignant cysts with negative cytologic evaluation (10/40) could be diagnosed as malignant by using DNA analysis. Limitations Limited follow-up, selection bias. Conclusions Elevated amounts of pancreatic cyst fluid DNA, high-amplitude mutations, and specific mutation acquisition sequences are indicators of malignancy. The presence of a k- ras mutation is also indicative of a mucinous cyst. DNA analysis should be considered when cyst cytologic examination is negative for malignancy.
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