Inactivation of MTOR promotes autophagy-mediated epithelial injury in particulate matter-induced airway inflammation.
TL;DR: The present study provides a mechanistic explanation for how airway epithelium localized MTOR-autophagy axis regulates PM-induced airway injury, suggesting that activation of MTOR and/or suppression of autophagy in local airway might be effective therapeutic strategies for PM-related airway disorders.
Abstract: Particulate matter (PM) is able to induce airway epithelial injury, while the detailed mechanisms remain unclear. Here we demonstrated that PM exposure inactivated MTOR (mechanistic target of rapam...
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01 Mar 2017
TL;DR: Recent advances in understanding of mTOR function, regulation, and importance in mammalian physiology are reviewed and how the mTOR-signaling network contributes to human disease is highlighted.
Abstract: The mechanistic target of rapamycin (mTOR) coordinates eukaryotic cell growth and metabolism with environmental inputs, including nutrients and growth factors. Extensive research over the past two decades has established a central role for mTOR in regulating many fundamental cell processes, from protein synthesis to autophagy, and deregulated mTOR signaling is implicated in the progression of cancer and diabetes, as well as the aging process. Here, we review recent advances in our understanding of mTOR function, regulation, and importance in mammalian physiology. We also highlight how the mTOR signaling network contributes to human disease and discuss the current and future prospects for therapeutically targeting mTOR in the clinic.
2,014 citations
TL;DR: This work has shown that exercise-mediated bidirectional regulation of autophagy can prevent cardiovascular diseases and therefore exercise training is beneficial to the cardiovascular system.
45 citations
TL;DR: A sub-chronic low level exposure to PM can have an adverse effect on lung health, which should be taken into consideration for the planning of roads and residential buildings.
Abstract: Air pollution is a ubiquitous problem and comprises gaseous and particulate matter (PM). Epidemiological studies have clearly shown that exposure to PM is associated with impaired lung function and...
45 citations
TL;DR: Wang et al. as mentioned in this paper investigated the protection of Astragaloside IV (AS-IV) from PM2.5-induced lung injury in rats and rat alveolar macrophages (NR8383 cells).
Abstract: Introduction Prolonged exposure to air polluted with airborne fine particulate matter (PM2.5) can increase respiratory disease risk. Astragaloside IV (AS-IV) is one of the main bioactive substances in the traditional Chinese medicinal herb, Astragalus membranaceus Bunge. AS-IV has numerous pharmacological properties; whereas there are few reports on the prevention of PM2.5-induced lung injury by AS-IV through modulation of the autophagic pathway. This study aimed to investigate the protective effects and the underlying mechanisms of AS-IV in PM2.5-induced lung injury rats and rat alveolar macrophages (NR8383 cells). Methods The pneumotoxicity model was established by intratracheal injection of PM2.5 in rats, and PM2.5 challenge in NR8383 cells. The severity of lung injury was evaluated by wet weight to dry weight ratio and McGuigan pathology scoring. Inflammatory factors and oxidative stress were detected through ELISA. The expressions of p-PI3K, p-Akt, and p-mTOR proteins were analyzed by immunohistochemistry. Immunofluorescence and transmission electron microscopy were used to detect autophagosomes. The expressions of autophagy marker protein (LC3B and p62), PI3K/Akt/mTOR signaling and NF-κB translocation were detected by Western blot in lung tissue and NR8383 cells. Results After PM2.5 stimulation, rats showed severe inflammation and oxidative stress, along with inhibition of autophagy in lung tissue. AS-IV not only decreased pulmonary inflammation and oxidative stress by inhibiting nuclear factor kappa B translocation, but also regulated autophagy by inhibiting PI3K/Akt/mTOR signaling. After treatment with 3-methyladenine (a classic PI3K inhibitor, blocking the formation of autophagosomes), the protective effect of AS-IV on PM2.5-induced lung injury was further strengthened. In parallel, using Western blot, immunohistochemistry, and transmission electron microscopy, we demonstrated that AS-IV restore autophagic flux mainly through regulating the degradation of autophagosomes rather than suppressing the formation in vivo and in vitro. Conclusion Our data indicated that AS-IV protects from PM2.5-induced lung injury in vivo and in vitro by inhibiting the PI3K/Akt/mTOR pathway to regulate autophagy and inflammation.
28 citations
TL;DR: E Epidemiological and experimental studies were reviewed in two parts according to the size and source of particles and various functions of the altered miRNAs were discussed and predicted potential biological mechanism participated in particulate matter-induced health effects.
25 citations
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TL;DR: Results of older bio-kinetic studies with NSPs and newer epidemiologic and toxicologic studies with airborne ultrafine particles can be viewed as the basis for the expanding field of nanotoxicology, which can be defined as safety evaluation of engineered nanostructures and nanodevices.
Abstract: Although humans have been exposed to airborne nanosized particles (NSPs; < 100 nm) throughout their evolutionary stages, such exposure has increased dramatically over the last century due to anthropogenic sources. The rapidly developing field of nanotechnology is likely to become yet another source through inhalation, ingestion, skin uptake, and injection of engineered nanomaterials. Information about safety and potential hazards is urgently needed. Results of older bio-kinetic studies with NSPs and newer epidemiologic and toxicologic studies with airborne ultrafine particles can be viewed as the basis for the expanding field of nanotoxicology, which can be defined as safety evaluation of engineered nanostructures and nanodevices. Collectively, some emerging concepts of nanotoxicology can be identified from the results of these studies. When inhaled, specific sizes of NSPs are efficiently deposited by diffusional mechanisms in all regions of the respiratory tract. The small size facilitates uptake into cells and transcytosis across epithelial and endothelial cells into the blood and lymph circulation to reach potentially sensitive target sites such as bone marrow, lymph nodes, spleen, and heart. Access to the central nervous system and ganglia via translocation along axons and dendrites of neurons has also been observed. NSPs penetrating the skin distribute via uptake into lymphatic channels. Endocytosis and biokinetics are largely dependent on NSP surface chemistry (coating) and in vivo surface modifications. The greater surface area per mass compared with larger-sized particles of the same chemistry renders NSPs more active biologically. This activity includes a potential for inflammatory and pro-oxidant, but also antioxidant, activity, which can explain early findings showing mixed results in terms of toxicity of NSPs to environmentally relevant species. Evidence of mitochondrial distribution and oxidative stress response after NSP endocytosis points to a need for basic research on their interactions with subcellular structures. Additional considerations for assessing safety of engineered NSPs include careful selections of appropriate and relevant doses/concentrations, the likelihood of increased effects in a compromised organism, and also the benefits of possible desirable effects. An interdisciplinary team approach (e.g., toxicology, materials science, medicine, molecular biology, and bioinformatics, to name a few) is mandatory for nanotoxicology research to arrive at an appropriate risk assessment.
7,092 citations
"Inactivation of MTOR promotes autop..." refers background in this paper
...Recently, several studies have already demonstrated that PM is able to deposit in the respiratory tract or come into alveoli, consequently induces impairment of airway epithelial barrier, oxidative stress, autophagy, DNA damage, and genomic instability [3,4]....
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TL;DR: Recent advances in understanding of mTOR function, regulation, and importance in mammalian physiology are reviewed and how the mTOR signaling network contributes to human disease is highlighted.
4,719 citations
TL;DR: This study suggests that autophagic proteins regulate NALP3-dependent inflammation by preserving mitochondria integrity and cytosolic translocation of mitochondrial DNA in response to lipopolysaccharide and ATP in macrophages.
Abstract: Autophagy, a cellular process for organelle and protein turnover, regulates innate immune responses. Here we demonstrate that depletion of the autophagic proteins LC3B and beclin 1 enhanced the activation of caspase-1 and secretion of interleukin 1β (IL-1β) and IL-18. Depletion of autophagic proteins promoted the accumulation of dysfunctional mitochondria and cytosolic translocation of mitochondrial DNA (mtDNA) in response to lipopolysaccharide (LPS) and ATP in macrophages. Release of mtDNA into the cytosol depended on the NALP3 inflammasome and mitochondrial reactive oxygen species (ROS). Cytosolic mtDNA contributed to the secretion of IL-1β and IL-18 in response to LPS and ATP. LC3B-deficient mice produced more caspase-1-dependent cytokines in two sepsis models and were susceptible to LPS-induced mortality. Our study suggests that autophagic proteins regulate NALP3-dependent inflammation by preserving mitochondrial integrity.
2,352 citations
01 Mar 2017
TL;DR: Recent advances in understanding of mTOR function, regulation, and importance in mammalian physiology are reviewed and how the mTOR-signaling network contributes to human disease is highlighted.
Abstract: The mechanistic target of rapamycin (mTOR) coordinates eukaryotic cell growth and metabolism with environmental inputs, including nutrients and growth factors. Extensive research over the past two decades has established a central role for mTOR in regulating many fundamental cell processes, from protein synthesis to autophagy, and deregulated mTOR signaling is implicated in the progression of cancer and diabetes, as well as the aging process. Here, we review recent advances in our understanding of mTOR function, regulation, and importance in mammalian physiology. We also highlight how the mTOR signaling network contributes to human disease and discuss the current and future prospects for therapeutically targeting mTOR in the clinic.
2,014 citations
"Inactivation of MTOR promotes autop..." refers background in this paper
...Generally, MTOR complex 1 is considered as the master regulator of autophagy [5,6]....
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...Extensive studies have established a dominant role for MTOR in regulating cellular growth and metabolism in response to growth factors and nutrients, and reveal that MTOR signaling pathway is implicated in the progression of cancer, obesity, type 2 diabetes, as well as the aging process [5]....
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TL;DR: In vivo and in vitro evidence supports the concept that the IL-6 system plays an unexpected positive role in local inflammatory reactions by amplifying leukocyte recruitment.
1,081 citations
"Inactivation of MTOR promotes autop..." refers background in this paper
...Additionally, IL6 induces the production of proinflammatory cytokines such as IL17 and IL23 via IL6RA (interleukin 6 receptor, alpha) in mature neutrophils to establish a Th17 cells-polarizing positive feedback loop [32,34]....
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