Abnormalities in the transition betweenα-helices andβ-sheets(α-βtransition)may lead to devastating neurodegenerative diseases,such as Parkinson's syndrome and Alzheimer's disease.Ionic liquids(ILs)are pote...Abnormalities in the transition betweenα-helices andβ-sheets(α-βtransition)may lead to devastating neurodegenerative diseases,such as Parkinson's syndrome and Alzheimer's disease.Ionic liquids(ILs)are potential drugs for targeted therapies against these diseases because of their excellent bioactivity and designability of ILs.However,the mechanism through which ILs regulate the aα-βtransition remains unclear.Herein,a combination of GPU-accelerated microsecond molecular dynamics simulations,correlation analysis,and machine learning was used to probe the dynamicalα-βtransition process induced by ILs of 1-alkyl-3-methylimidazolium chloride([C_(n)mim]cl)and its molecular mechanism.Interestingly,the cation of [C_(n)mim]+in ILs can spontaneously insert into the peptides as free ions(n≤10)and clusters(n≥11).Such insertion can significantly inhibit theα-β,transition and the inhibiting ability for the clusters is more significant than that of free ions,where[Ciomim]+and[C_(12)mim]+can reduce the maximumβ-sheet content of the peptide by 18.5% and 44.9%,respectively.Furthermore,the correlation analysis and machine learning method were used to develop a predictive model accounting for the influencing factors on theα-βtransition,which could accurately predict the effect of ILs on theα-βtransition.Overall,these quantitative results may not only deepen the understanding of the role of ILs in theα-βtransition but also guide the development of the IL-based treatments for related diseases.展开更多
Objective To investigate changes in the delayed rectifier K + channel (Kv) function and the regulation of Kv by the protein kinase C (PKC) pathway in bronchial myocytes from asthmatic rats. Methods The Kv currents an...Objective To investigate changes in the delayed rectifier K + channel (Kv) function and the regulation of Kv by the protein kinase C (PKC) pathway in bronchial myocytes from asthmatic rats. Methods The Kv currents and membrane potentials in bronchial myocytes from asthmatic rats and from controls were observed, using whole cell voltage- and current-patch clamp techniques.Results Bronchial myocytes from asthmatic rats showed a significant reduction in Kv-current density (51.6±9.4 pA/pF, n=14, P<0.01) in comparison with those from control rats (72.4±12.3 pA/pF, n=14) at +50 mV. The current-voltage relationship curve exhibited a significant downward shift. Bronchial myocytes from asthmatic rats had no significantly different capacitances (P>0.05), but had more positive membrane potential ( P<0.01) compared with those from controls. 1 μmol/L phorbol 12-myristate 13-acetate, a PKC activator, caused an obvious reduction in Kv-current density (P<0.01) and a significant downward shift in the current-voltage relationship curve, an effect which was partly abolished by 1 μmol/L Ro31-8220 (a PKC inhibitor); 1 μmol/L phorbol 12-myristate 13-acetate caused more positive membrane potential (Em), from -36.8±5.7 mV to -30.4±7.3 mV, in rat bronchial myocytes (P<0.05). This effect was partly abolished by 1 μmol/L Ro31-8220. Conclusions Bronchial myocytes from asthmatic rats have inhibited Kv function, more positive membrane potential, and higher excitability, all of which can also be induced by PKC activation. These characteristics may contribute to the development of airway hyperreactivity in asthma.展开更多
Background Hypoxic pulmonary hypertension (HPH) is initiated by inhibition of O 2 sensitive, voltage gated (Kv) channels in pulmonary arterial smooth muscle cells (PASMCs) The mechanism of hypoxic pulmonary hyp...Background Hypoxic pulmonary hypertension (HPH) is initiated by inhibition of O 2 sensitive, voltage gated (Kv) channels in pulmonary arterial smooth muscle cells (PASMCs) The mechanism of hypoxic pulmonary hypertension has not yet been fully elucidated The mitochondrial ATP sensitive K + channel (MitoK ATP ) is extremely sensitive to hypoxia, and is a decisive factor in the control of mitochondrial membrane potential (ΔΨ m) This study investigated the changes of cell membrane potential and Kv channel in cultured human pulmonary artery smooth muscle cell (hPASMC) exposed to 24 hour hypoxia, and explored the role of MitoK ATP and ΔΨ m in this condition Methods Fresh human lung tissues were obtained from the patients undergoing a chest operation hPASMCs were isolated, cultured, and divided into 6 groups: ① control group, cultured under normoxia; ② diazoxide group, cultured in normoxia with diazoxide, an opener of MitoK ATP ; ③ 5 HD group, cultured in normoxia with sodium 5 hydroxydecanoate (5 HD), an antagonist of MitoK ATP ; ④ 24 hour hypoxia group; ⑤ 24 hour hypoxia + diazoxide group; and ⑥ 24 hour hypoxia + 5HD group Whole cell patch clamp technique was used to trace the cell membrane K + currents The expressions of cell membrane Kv1 5 mRNA and protein were determined by RT PCR and Western blot technique, respectively The relative changes in mitochondrial potential were tested with rhodamine fluorescence (R 123) technique Results After exposure to diazoxide for 24 hours, the intensity of R 123 fluorescence in normoxic hPASMCs was significantly increased compared with control group ( P <0 05), but there were no significant changes in these tests after the hPASMCs had been exposed to 5 HD for 24 hours Twenty four hour hypoxia or 24 hour hypoxia + diazoxide could markedly increase the intensity of R 123 fluorescence in hPASMC and the changes were more significant in 24 hour hypoxia +diazoxide group than in 24 hour hypoxia group ( P <0 05) although 5 HD could partly weaken the effect of 24 hour hypoxia on the intensity of R 123 fluorescence After exposure to diazoxide for 24 hours, the cell membrane K + currents and the expression of cell membrane Kv1 5 mRNA and protein in normoxic hPASMCs were significantly decreased compared with control group ( P <0 05), but there were no significant changes in these tests after the hPASMCs had been exposed to 5 HD for 24 hours Also, 24 hour hypoxia or 24 hour hypoxia + diazoxide decreased the cell membrane K + currents and the expression of Kv1 5 mRNA and protein ( P <0 05) but the changes were more significant in 24 hour hypoxia + diazoxide group than in 24 hour hypoxia group ( P <0 05) Again, 5 HD could partly weaken the inhibitory effect of 24 hour hypoxia on the cell membrane K + currents and the expression of Kv1 5 mRNA or protein ( P <0 05) Conclusions The opening of MitoK ATP followed by a depolarization of ΔΨ m in hypoxia might contribute to the alterations in the expression of cell membrane Kv1 5 mRNA and protein leading to change in the cell membrane potential of hypoxic hPASMCs This might be a mechanism of the development of hypoxic pulmonary hypertension展开更多
The genetic bases and molecular mechanisms involved in the assembly and function of the flagellum components as well as in the regulation of the flagellar movement are not fully understood, especially in humans. There...The genetic bases and molecular mechanisms involved in the assembly and function of the flagellum components as well as in the regulation of the flagellar movement are not fully understood, especially in humans. There are several causes for sperm immotility, of which some can be avoided and corrected, whereas other are related to genetic defects and deserve full investigation to give a diagnosis to patients. This review was performed after an extensive literature search on the online databases PubMed, ScienceDirect, and Web of Science. Here, we review the involvement of regulatory pathways responsible for sperm motility, indicating possible causes for sperm immotility. These included the calcium pathway, the cAMP-dependent protein kinase pathway, the importance of kinases and phosphatases, the function of reactive oxygen species, and how the regulation of cell volume and osmolarity are also fundamental components. We then discuss main gene defects associated with specific morphological abnormalities. Finally, we slightly discuss some preventive and treatments approaches to avoid development of conditions that are associated with unspecified sperm immotility. We believe that in the near future, with the development of more powerful techniques, the genetic causes of sperm immotility and the regulatory mechanisms of sperm motility will be better understand, thus enabling to perform a full diagnosis and uncover new therapies.展开更多
Rebound depolarization （RD） is a response to the offset from hyperpolarization of the neuronal mem- brane potential and is an important mechanism for the synaptic processing of inhibitory signals. In the present stu...Rebound depolarization （RD） is a response to the offset from hyperpolarization of the neuronal mem- brane potential and is an important mechanism for the synaptic processing of inhibitory signals. In the present study, we characterized RD in neurons of the rat medial geniculate body （MGB）, a nucleus of the auditory thala- mus, using whole-cell patch-clamp and brain slices. RD was proportional in strength to the duration and magnitude of the hyperpolarization; was effectively blocked by Ni2＋ or Mibefradil; and was depressed when the resting membrane potential was hyperpolarized by blocking hyperpolarization-activated cyclic nucleotide-gated （HCN） channels with ZD7288 or by activating G-protein-gated inwardly-rectifying K＋ （GIRK） channels with baclofen. Our results demonstrated that RD in MGB neurons, which is carried by T-type Ca2＋ channels, is critically regulated by HCN channels and likely by GIRK channels.展开更多
基金the National Natural Science Foundation of China(21834006,22078322,21978293,and 21978027)the Youth Innovation Promotion Association of CAS(2021046,Y2021046)State Key Laboratory of Treatments and Recycling for Organic Effluents by Adsorption in Petroleum and Chemical Industry(SDHY2114).
文摘Abnormalities in the transition betweenα-helices andβ-sheets(α-βtransition)may lead to devastating neurodegenerative diseases,such as Parkinson's syndrome and Alzheimer's disease.Ionic liquids(ILs)are potential drugs for targeted therapies against these diseases because of their excellent bioactivity and designability of ILs.However,the mechanism through which ILs regulate the aα-βtransition remains unclear.Herein,a combination of GPU-accelerated microsecond molecular dynamics simulations,correlation analysis,and machine learning was used to probe the dynamicalα-βtransition process induced by ILs of 1-alkyl-3-methylimidazolium chloride([C_(n)mim]cl)and its molecular mechanism.Interestingly,the cation of [C_(n)mim]+in ILs can spontaneously insert into the peptides as free ions(n≤10)and clusters(n≥11).Such insertion can significantly inhibit theα-β,transition and the inhibiting ability for the clusters is more significant than that of free ions,where[Ciomim]+and[C_(12)mim]+can reduce the maximumβ-sheet content of the peptide by 18.5% and 44.9%,respectively.Furthermore,the correlation analysis and machine learning method were used to develop a predictive model accounting for the influencing factors on theα-βtransition,which could accurately predict the effect of ILs on theα-βtransition.Overall,these quantitative results may not only deepen the understanding of the role of ILs in theα-βtransition but also guide the development of the IL-based treatments for related diseases.
基金ThisstudywassupportedbytheNationalNaturalScienceFoundationofChina (No 3 0 2 70 5 83 ) .
文摘Objective To investigate changes in the delayed rectifier K + channel (Kv) function and the regulation of Kv by the protein kinase C (PKC) pathway in bronchial myocytes from asthmatic rats. Methods The Kv currents and membrane potentials in bronchial myocytes from asthmatic rats and from controls were observed, using whole cell voltage- and current-patch clamp techniques.Results Bronchial myocytes from asthmatic rats showed a significant reduction in Kv-current density (51.6±9.4 pA/pF, n=14, P<0.01) in comparison with those from control rats (72.4±12.3 pA/pF, n=14) at +50 mV. The current-voltage relationship curve exhibited a significant downward shift. Bronchial myocytes from asthmatic rats had no significantly different capacitances (P>0.05), but had more positive membrane potential ( P<0.01) compared with those from controls. 1 μmol/L phorbol 12-myristate 13-acetate, a PKC activator, caused an obvious reduction in Kv-current density (P<0.01) and a significant downward shift in the current-voltage relationship curve, an effect which was partly abolished by 1 μmol/L Ro31-8220 (a PKC inhibitor); 1 μmol/L phorbol 12-myristate 13-acetate caused more positive membrane potential (Em), from -36.8±5.7 mV to -30.4±7.3 mV, in rat bronchial myocytes (P<0.05). This effect was partly abolished by 1 μmol/L Ro31-8220. Conclusions Bronchial myocytes from asthmatic rats have inhibited Kv function, more positive membrane potential, and higher excitability, all of which can also be induced by PKC activation. These characteristics may contribute to the development of airway hyperreactivity in asthma.
基金Thestudywassupportedbya grantfromtheNationalNaturalScienceFoundationofChina (No 3 0 3 70 62 3 )
文摘Background Hypoxic pulmonary hypertension (HPH) is initiated by inhibition of O 2 sensitive, voltage gated (Kv) channels in pulmonary arterial smooth muscle cells (PASMCs) The mechanism of hypoxic pulmonary hypertension has not yet been fully elucidated The mitochondrial ATP sensitive K + channel (MitoK ATP ) is extremely sensitive to hypoxia, and is a decisive factor in the control of mitochondrial membrane potential (ΔΨ m) This study investigated the changes of cell membrane potential and Kv channel in cultured human pulmonary artery smooth muscle cell (hPASMC) exposed to 24 hour hypoxia, and explored the role of MitoK ATP and ΔΨ m in this condition Methods Fresh human lung tissues were obtained from the patients undergoing a chest operation hPASMCs were isolated, cultured, and divided into 6 groups: ① control group, cultured under normoxia; ② diazoxide group, cultured in normoxia with diazoxide, an opener of MitoK ATP ; ③ 5 HD group, cultured in normoxia with sodium 5 hydroxydecanoate (5 HD), an antagonist of MitoK ATP ; ④ 24 hour hypoxia group; ⑤ 24 hour hypoxia + diazoxide group; and ⑥ 24 hour hypoxia + 5HD group Whole cell patch clamp technique was used to trace the cell membrane K + currents The expressions of cell membrane Kv1 5 mRNA and protein were determined by RT PCR and Western blot technique, respectively The relative changes in mitochondrial potential were tested with rhodamine fluorescence (R 123) technique Results After exposure to diazoxide for 24 hours, the intensity of R 123 fluorescence in normoxic hPASMCs was significantly increased compared with control group ( P <0 05), but there were no significant changes in these tests after the hPASMCs had been exposed to 5 HD for 24 hours Twenty four hour hypoxia or 24 hour hypoxia + diazoxide could markedly increase the intensity of R 123 fluorescence in hPASMC and the changes were more significant in 24 hour hypoxia +diazoxide group than in 24 hour hypoxia group ( P <0 05) although 5 HD could partly weaken the effect of 24 hour hypoxia on the intensity of R 123 fluorescence After exposure to diazoxide for 24 hours, the cell membrane K + currents and the expression of cell membrane Kv1 5 mRNA and protein in normoxic hPASMCs were significantly decreased compared with control group ( P <0 05), but there were no significant changes in these tests after the hPASMCs had been exposed to 5 HD for 24 hours Also, 24 hour hypoxia or 24 hour hypoxia + diazoxide decreased the cell membrane K + currents and the expression of Kv1 5 mRNA and protein ( P <0 05) but the changes were more significant in 24 hour hypoxia + diazoxide group than in 24 hour hypoxia group ( P <0 05) Again, 5 HD could partly weaken the inhibitory effect of 24 hour hypoxia on the cell membrane K + currents and the expression of Kv1 5 mRNA or protein ( P <0 05) Conclusions The opening of MitoK ATP followed by a depolarization of ΔΨ m in hypoxia might contribute to the alterations in the expression of cell membrane Kv1 5 mRNA and protein leading to change in the cell membrane potential of hypoxic hPASMCs This might be a mechanism of the development of hypoxic pulmonary hypertension
文摘The genetic bases and molecular mechanisms involved in the assembly and function of the flagellum components as well as in the regulation of the flagellar movement are not fully understood, especially in humans. There are several causes for sperm immotility, of which some can be avoided and corrected, whereas other are related to genetic defects and deserve full investigation to give a diagnosis to patients. This review was performed after an extensive literature search on the online databases PubMed, ScienceDirect, and Web of Science. Here, we review the involvement of regulatory pathways responsible for sperm motility, indicating possible causes for sperm immotility. These included the calcium pathway, the cAMP-dependent protein kinase pathway, the importance of kinases and phosphatases, the function of reactive oxygen species, and how the regulation of cell volume and osmolarity are also fundamental components. We then discuss main gene defects associated with specific morphological abnormalities. Finally, we slightly discuss some preventive and treatments approaches to avoid development of conditions that are associated with unspecified sperm immotility. We believe that in the near future, with the development of more powerful techniques, the genetic causes of sperm immotility and the regulatory mechanisms of sperm motility will be better understand, thus enabling to perform a full diagnosis and uncover new therapies.
基金supported by the National Basic Research Development Program of China(2011CB504506 and2012CB932502)the National Natural Science Foundation of China(81570915,81371503 and 31170965)the Open Fund from CAS Key Laboratory of Brain Function and Diseases,China(2012-3)
文摘Rebound depolarization （RD） is a response to the offset from hyperpolarization of the neuronal mem- brane potential and is an important mechanism for the synaptic processing of inhibitory signals. In the present study, we characterized RD in neurons of the rat medial geniculate body （MGB）, a nucleus of the auditory thala- mus, using whole-cell patch-clamp and brain slices. RD was proportional in strength to the duration and magnitude of the hyperpolarization; was effectively blocked by Ni2＋ or Mibefradil; and was depressed when the resting membrane potential was hyperpolarized by blocking hyperpolarization-activated cyclic nucleotide-gated （HCN） channels with ZD7288 or by activating G-protein-gated inwardly-rectifying K＋ （GIRK） channels with baclofen. Our results demonstrated that RD in MGB neurons, which is carried by T-type Ca2＋ channels, is critically regulated by HCN channels and likely by GIRK channels.
