Recombinant protein of the first two ectodomains of cadherin 23 from erl mice shows impairment in Ca2+-dependent proteolysis protection

The erl mouse is a mouse model of nonsyndromic autosomal recessive deafness (DFNB12) on the C57BL/6J background. This project was carried out to express the first two ectodomains of cadherin 23 (CDH23 EC1+2) of erl mice in Escherichia coli and identify the Ca²⁺-binding ability of the recombinant protein. DNA sequences of CDH23 EC1+2 from wild type and erl mice were synthesized and cloned into pBV220 plasmids. Recombinant plasmids were transformed into Escherichia coli and expression of CDH23 EC1+2 was induced by increasing the temperature from 30 °C to 42 °C. The proteins were analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and antigenicity of proteins was identified by Western Blotting. Inclusion bodies were denatured in 8 M urea, purified by ion-exchange and gel filtration chromatography and refolded with dialysis in buffer containing 0.1% sarkosyl. The Ca²⁺-binding ability of CDH23 EC1+2 was determined by Ca²⁺-dependent proteolysis protection. The results showed that the sizes and sequences of inserts in recombinant plasmids were consistent with expectation and that the recombinant proteins were found mainly in the form of inclusion bodies which maintain antigenicity. After refolding, the secondary structures of recombinant proteins were measured by circular dichroism (CD) spectra. Moreover, CDH23 EC1+2 from the erl mice showed less Ca²⁺-dependent proteolysis protection comparing with that of the wild type control. We therefore concluded that impairment of Ca²⁺-dependent protein interaction was likely involved in the progressive hearing loss in erl mice. The results may aid in understanding the mechanism of hearing loss in DFNB12.

Ribonucleic acid interference knockdown of IL-6 enhances the efficacy of cisplatin in laryngeal cancer stem cells by down-regulating the IL-6/STAT3/HIF1 pathway

Background

Cisplatin has been used in the treatment of many cancers, including laryngeal cancer; however, its efficacy can be reduced due to the development of drug resistance. This study aimed to investigate whether interleukin-6 (IL-6) knockdown may enhance the efficacy of cisplatin in laryngeal cancer stem cells (CSC) and the potential involvement of the signal transducer and activator of transcription 3 (STAT3) and hypoxia-inducible factor 1 (HIF1) in this effect.

Methods

The ALDH+ and CD44+ CSC in Hep2 human laryngeal squamous cancer cells were identified by the fluorescence-activated cell sorting technique. IL-6, STAT3 and HIF1 mRNA and protein expressions were examined with quantitative real-time polymerase chain reaction and Western blot, respectively. Cell proliferation was measured by MTT assay. Tumorigenicity was measured by a colony formation assay and invasion was determined by a cell invasion assay. Apoptotic cells were counted by flow cytometry. Immunohistochemistry was performed to detect immunoreactive IL-6, STAT3 and HIF1 cells in xenografts.

Results

The mRNA and protein levels of IL-6, STAT3 and HIF1 were significantly increased in Hep2-CSC as compared with those from Hep2 cells. Application of siRNA-IL-6 to knockdown IL-6 resulted in significantly decreased IL-6, STAT3 and HIF1 mRNA and protein levels. IL-6 knockdown reduced cell proliferation, tumorigenicity and invasion and increased apoptosis within CSC. Enhanced degrees of suppression in these parameters were observed when IL-6 knockdown was combined with cisplatin in these CSC. Results from the xenograft study showed that the combination of IL-6 knockdown and cisplatin further inhibited the growth of xenografts as compared with that obtained in the cisplatin-injected group alone. Immunoreactive IL-6, STAT3 and HIF1 cell numbers were markedly reduced in IL-6 knockdown tumor tissues. IL-6, STAT3 and HIF1 immunoreactive cell counts were further reduced in tissue where IL-6 knockdown was combined with cisplatin treatment as compared with tissue receiving cisplatin alone.

Conclusions

IL-6 knockdown can increase chemo-drug efficacy of cisplatin, inhibit tumor growth and reduce the potential for tumor recurrence and metastasis in laryngeal cancer. The IL-6/STAT3/HIF1 pathway may represent an important target for investigating therapeutic strategies for the treatment of laryngeal cancer.

DNMT3A-mediated down-regulation of microRNA-105 promotes gastric cancer cell proliferation

OBJECTIVE

It has been well-established that microRNAs (miRNAs), a class of short non-coding RNA molecules, play an important role in the development of gastric cancer. In the present study, we focused on miR-105, a novel miRNA not previously linked to gastric cancer.

PATIENTS AND METHODS

36 paired surgically resected gastric cancer tissues and matched adjacent normal tissues were used to detect the expression of miR-105. AGS cells were used to overexpress or silence of miR-105 and to determine its effect on several tumorigenic properties. A cell proliferation enzyme-linked immunosorbent assay was used to analyze the incorporation of BrdU during DNA synthesis of AGS cells. Total cDNA from AGS cells was used to amplify the 3'-UTR of YY1 by PCR and luciferase activity was determined using the Dual-Luciferase Reporter Assay System RESULTS: We found that expression of miR-105 was reduced in gastric cancer tissues, compared with adjacent normal tissues, due to hypermethylation at its promoter region. Overexpression of miR-105 suppressed, whereas its inhibition promoted cell viability and proliferation. We further identified Yin Yang 1 (YY1) as a direct target of miR-105, by which miR-105 exerted its anti-proliferative role. Moreover, we found that DNMT3A was responsible for the down-regulation of miR-105 in gastric cancer cells.

CONCLUSIONS

Our data demonstrate that miR-105 inhibits gastric cancer cell proliferation and progression, which might provide a therapeutical target for cancer therapy.

[Mass spectrometry combined with gene analysis for prenatal diagnosis of glutaric acidemia type Ⅰ]

Objective: To investigate the value of amniotic fluid metabolite detection by mass spectrometry combined with gene mutation analysis in the prenatal diagnosis of glutaric acidemia type Ⅰ (GA-Ⅰ). Method: From January 2009 to December 2016, Department of Pediatric Endocrinology and Genetic, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine carried out prenatal diagnosis for 24 cases of pregnant women with GA-Ⅰproband. 24 pregnant women without organic acidemia proband for conventional prenatal diagnosis at the same period were used as the control group. The pregnant women of the two groups had the amniocentesis at 16 to 20 weeks of gestation.The levels of glutaryl carnitine (C5DC) and octanoylcarnitine (C8) in amniotic fluid were detected by tandem mass spectrometry, and the levels of glutaric acid was determined by gas chromatography-mass spectrometry. All the amniotic fluid cells underwent GCDH gene testing. Result: A total of 4 cases of fetuses were diagnosed by gene mutation analysis combined with mass spectrometry detection, the levels of C5DC (1.58(0.89-2.85) μmol/L), C5DC/C8 (19.74(12.40-25.93))and glutaric acid (129.96 (90.09-66.02) mmol/mol Cr) were significantly higher than the upper limit of the reference, of which in one case with the proband only on mutation was detected, and in the amniotic fluid cells also only one mutation was detected, the diagnosis was made according to the significantly increased levels of amniotic fluid C5DC, C5DC/C8 and glutaric acid. Twenty cases of fetuses were identified as non-GA-Ⅰchildren, of whom in 2 cases of proband only one mutation was detected, and also in amniotic fluid cells one mutation was detected, in 2 cases the diagnosis was excluded because the normal levels of C5DC, C5DC/C8 and glutaric acid. There were 2 cases whose levels of C5DC or glutaric acid were slightly higher than the upper limit of the reference, but the diagnosis was excluded according to genetic testing. Conclusion: Prenatal diagnosis cannot be made by gene analysis when the proband mutation is not clear, and it cannot determine whether the fetus is patient when the mass spectrometry detection of amniotic fluid metabolite is mildly abnormal, while mass spectrometry detection of amniotic fluid C5DC, C5DC/C8 and glutaric acid levels combined with GCDH gene analysis can make up the deficiencies, and make the prenatal diagnosis of GA-Ⅰ more reliably.

[Effects of hypoxia on the phenotype transformation of human dermal fibroblasts to myofibroblasts and the mechanism]

Objective: To investigate the effects of hypoxia on the phenotype transformation of human dermal fibroblasts to myofibroblasts and the mechanism. Methods: The third passage of healthy adult human dermal fibroblasts in logarithmic phase were cultured in DMEM medium containing 10% fetal bovine serum for the following five experiments. (1) In experiments 1, 2, and 3, cells were divided into normoxia group and hypoxia group according to the random number table, with 10 dishes in each group. Cells of normoxia group were cultured in incubator containing 21% oxygen, while those of hypoxia group with 1% oxygen. At post culture hour (PCH) 0 and 48, 5 dishes of cells were collected from each group, respectively. mRNA expressions of markers of myofibroblasts including alpha smooth muscle actin (α-SMA), type Ⅰ collagen, and type Ⅲ collagen of cells were determined with real time fluorescent quantitative reverse transcription polymerase chain reaction in experiment 1. Protein expressions of α-SMA, type Ⅰ collagen, and type Ⅲ collagen of cells were determined with Western blotting in experiment 2. The protein expression of nuclear factor-kappa B (NF-κB) of cells was determined with Western blotting in experiment 3. (2) In experiment 4, cells were divided into normoxia group, hypoxia group, and hypoxia+ pyrrolidine dithiocarbamate (PDTC) group according to the random number table, with 5 dishes in each group. Cells in the former two groups were treated the same as those in experiment 1. Cells in hypoxia+ PDTC group were treated the same as those in hypoxia group plus adding 4 mL PDTC with a final molarity of 10 μmol/L in the culture medium. At PCH 48, the protein expression of NF-κB of cells was determined with Western blotting. (3) In experiment 5, cells were divided into normoxia group, hypoxia group, hypoxia+ PDTC group, and normoxia+ PDTC group according to the random number table, with 5 dishes in each group. Cells in the former three groups were treated the same as those in experiment 4. Cells in normoxia+ PDTC group were treated the same as those in normoxia group plus adding 4 mL PDTC with a final molarity of 10 μmol/L in the culture medium. At PCH 48, protein expressions of α-SMA, type Ⅰ collagen, and type Ⅲ collagen of cells were determined with Western blotting. Data were processed with analysis of variance of factorial design, one-way analysis of variance, and LSD-t test. Results: (1) Compared with those of normoxia group at corresponding time point, mRNA expressions and protein expressions of α-SMA, type Ⅰ collagen, and type Ⅲ collagen and the protein expression of NF-κB in fibroblasts of hypoxia group were not changed obviously at PCH 0 (with t values from -1.21 to 2.04, P values above 0.05), while mRNA expressions and protein expressions of α-SMA, type Ⅰ collagen, and type Ⅲ collagen and the protein expression of NF-κB significantly increased at PCH 48 (with t values from -12.57 to -3.44, P values below 0.01). (2) At PCH 48, the protein expression of NF-κB in fibroblasts of hypoxia group was 0.83±0.12, significantly higher than that of normoxia group (0.17±0.06, t=-16.96, P<0.001). The protein expression of NF-κB in fibroblasts of hypoxia+ PDTC group was 0.31±0.08, significantly lower than that of hypoxia group (t=12.73, P<0.001). (3) At PCH 48, protein expressions of α-SMA, type Ⅰ collagen, and type Ⅲ collagen in fibroblasts of hypoxia group were 0.73±0.09, 1.25±0.10, and 1.16±0.07, respectively, significantly higher than those of normoxia group (0.14±0.06, 0.87±0.08, and 0.77±0.13, respectively, with t values from 9.24 to 11.24, P values below 0.001). The protein expression of α-SMA in fibroblasts of normoxia+ PDTC group was 0.24±0.07, significantly higher than that of normoxia group (t=4.22, P<0.01). Protein expressions of type Ⅰ collagen and type Ⅲ collagen in fibroblasts of normoxia+ PDTC group were 0.25±0.06 and 0.32±0.11, respectively, significantly lower than those of normoxia group (with t values respectively -4.31 and -3.88, P values below 0.01). Protein expressions of α-SMA, type Ⅰ collagen, and type Ⅲ collagen in fibroblasts of hypoxia+ PDTC group were 0.09±0.08, 0.38±0.12, and 0.47±0.08, respectively, significantly lower than those of hypoxia group (with t values from 11.78 to 22.98, P values below 0.001). Conclusions: Hypoxia can significantly up-regulate the expressions of α-SMA, type Ⅰ collagen, and type Ⅲ collagen in human dermal fibroblasts, which may promote the phenotype transformation of fibroblasts to myofibroblasts, and this is likely to be associated with the activation of NF-κB signal pathway.

Characterization of an entomopathogenic fungi target integument protein, Bombyx mori single domain von Willebrand factor type C, in the silkworm, Bombyx mori

The insect cuticle works as the first line of defence to protect insects from pathogenic infections and water evaporation. However, the old cuticle must be shed in order to enter the next developmental stage. During each ecdysis, moulting fluids are produced and secreted into the area among the old and new cuticles. In a previous study, the protein Bombyx mori single domain von Willebrand factor type C (BmSVWC; BGIBMGA011399) was identified in the moulting fluids of Bo. mori and demonstrated to regulate ecdysis. In this study we show that in Bo. mori larvae, BmSVWC primarily locates to the integument (epidermal cells and cuticle), wing discs and head. During the moulting stage, BmSVWC is released into the moulting fluids, and is then produced again by epidermal cells after ecdysis. Fungal infection was shown to decrease the amount of BmSVWC in the cuticle, which indicates that BmSVWC is a target protein of entomopathogenic fungi. Thus, BmSVWC is mainly involved in maintaining the integrity of the integument structure, which serves to protect insects from physical damage and pathogenic infection.

[Clinical presentation of Kleine-Levin syndrome]

Objective: To analyze the clinical features of Kleine-Levin syndrome (KLS) patients. Methods: Clinical data of 44 patients with KLS of the Sleep Center of Peking University People's Hospital from January 2002 to July 2013 were systematically reviewed. The predisposing factors and clinical presentations were summarized, and compared with the data from a Western KLS study with a large subjects number. Nocturnal polysomnography (PSG) and multiple sleep latency test (MSLT) were conducted during relapse and remission period, respectively. HLA-DQB1*0602 gene were screened and analyzed. Results: Among the 44 patients, 28(63.6%) were men and 16(36.4%) were women, with a mean age of (18.3±8.9) years old. Most patients developed the symptoms during adolescence. Infection or fever was the most common trigger for episode. The main clinical presentations were 44(100.0%) hypersomnia, 31(70.5%) forgetfulness, 26(59.1%) decreased appetites, 24(54.5%) juvenile behavior, 18(40.9%) depression, etc. Compared with the Western study, it showed that our patients had decreased instead of increased appetite. The PSG testing did not have remarkable findings. MSLT showed mean sleep latency was significantly shorter during relapse than during remission [(10.4±5.4) vs (15.3±3.4) min, P=0.009]. HLA-DQB1*0602 was positive in 12 of 40(30.0%) patients, which was similar to the data in the Chinese population. Conclusions: KLS has various clinical characteristics. The presentation of appetite may be different between Chinese and western KLS patients.

[Correlation of gastric cancer and effects of vitamin D receptor gene FokⅠ polymorphism on C-reactive protein and D-dimer in Uygur nationality patients]

OBJECTIVE

This study aimed to determine the correlation of Uygur gastric cancer and the polymorphism effects of vitamin D receptor gene FokⅠ on C-reactive protein and D-dimer.

METHODS

Method of random sampling was used to select 147 Uygur patients with gastric cancer who admitted at Tumor Hospital of Xinjing Medical University (Group A) and 151 healthy controls with the same nationality (Group B). Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method was used to determine FokⅠ loci polymorphism in both groups to identify the gastric cancer susceptibility gene. All patients were divided into Group FF (Group a) and Group Ff+ ff (Group b) by PCR-RFLP according to the f-gene carrier to compare the expression level of C-reactive protein and D-dimer.

RESULTS

The expression frequency of the f allelic gene of patients with gastric cancer was higher than that of healthy control patients (57.8% vs 47.4%, P<0.05). The carriers of the f allelic gene (Ff+ ff) had increased risk of gastric cancer (OR=2.85). Measurement levels of C-reactive protein and D-dimer in the f allelic gene group were higher than those of the non-f allelic gene group (4.72±1.65 vs 2.81±0.93, and 2.79±1.21 vs 1.09±0.65, respectively), and the differences were statistically significant (P<0.05).

CONCLUSIONS

The FokⅠ loci polymorphism of vitamin D receptor gene was related to gastric cancer susceptibility in Uygur. f allelic gene may be one of the risk factors of gastric cancer in Uygur. Moreover, f allelic gene may be a factor that increased the level of C-reactive protein and D-dimer in Uygur patients with gastric cancer.

Hearing Improvement in A/J Mice via the Mouse Nerve Growth Factor

Objectives

To investigate the otoprotective effects of mouse nerve growth factor (mNGF) in A/J mice.

Methods

The mice at postnatal day 7 (P7) were randomly separated into a mNGF treated group (mNGF group) and a distilled water (for injection) treated group (control group). The mNGF dissolved in distilled water or distilled water alone was given to the mice once every other day from P7 by intramuscular injection in the hips. The otoprotective effects of mNGF in A/J mice were observed in a time course manner. The thresholds of auditory-evoked brainstem response (ABR) were tested from the age of the 3rd to the 8th week. Sections of the inner ears were stained by hematoxylin and eosin, and spiral ganglion neurons (SGNs) were observed at the age of the 3rd, the 6th,and the 8th week. Counts of whole mount outer hair cells (OHCs) in the cochleae were made at the age of 8 weeks. Expression of apoptosis related genes was determined by quantitative real-time polymerase chain reaction and Western blotting.

Results

ABR thresholds of the mNGF group were significantly lower than those of the control group at the age of the 6th and the 8th week. Moreover, the mNGF preserved OHC and SGN in the mouse cochleae in this period. Further experiments showed that the expression of caspase genes (including caspase-3) was inhibited in the mouse inner ears in the mNGF group.

Conclusion

The mNGF improves hearing in A/J mice by preserving SGN and OHC in the cochleae.

High-salt diet induces outward remodelling of efferent arterioles in mice with reduced renal mass

AIM

The glomerular filtration rate (GFR) falls progressively in chronic kidney disease (CKD) which is caused by a reduction in the number of functional nephrons. The dysfunctional nephron exhibits a lower glomerular capillary pressure that is induced by an unbalance between afferent and efferent arteriole. Therefore, we tested the hypothesis that oxidative stress induced by CKD differentially impairs the structure or function of efferent vs. afferent arterioles.

METHODS

C57BL/6 mice received sham operations (sham) or 5/6 nephrectomy (RRM) and three months of normal- or high-salt diet or tempol. GFR was assessed from the plasma inulin clearance, arteriolar remodelling from media/lumen area ratio, myogenic responses from changes in luminal diameter with increases in perfusion pressure and passive wall compliance from the wall stress/strain relationships.

RESULTS

Mice with RRM fed a high salt (vs. sham) had a lower GFR (553 ± 25 vs. 758 ± 36 μL min^-1  g^-1 kidney, P < 0.01) and a larger efferent arteriolar diameter (9.6 ± 0.8 vs. 7.4 ± 0.7 μm, P < 0.05) resulting in a lower media/lumen area ratio (1.4 ± 0.1 vs. 2.4 ± 0.2, P < 0.01). These alterations were corrected by tempol. The myogenic responses of efferent arterioles were about one-half that of afferent arterioles and were unaffected by RRM or salt. Passive wall compliance was reduced by high salt in both afferent and efferent arterioles.

CONCLUSION

A reduction in renal mass with a high-salt diet induces oxidative stress that leads to an outward eutrophic remodelling in efferent arterioles and reduced wall compliance in both afferent and efferent arterioles. This may contribute to the lower GFR in this model of CKD.

Homozygous DNAH1 frameshift mutation causes multiple morphological anomalies of the sperm flagella in Chinese

This study aimed to investigate the genetic pathogeny of multiple morphological anomalies of the flagella (MMAF), which is a genetically heterogeneous disorder leading to male infertility. Nine patients with severe asthenozoospermia caused by MMAF were recruited. Whole genome sequencing and Sanger sequencing were performed, and we found that four of the nine patients were affected by the same homozygous frameshift mutation c.11726_11727delCT (p.[Pro3909ArgfsTer33]) in exon 73 of dynein axonemal heavy chain 1 ( DNAH1 ) gene. The parents and the sibling of proband 1 were all identified as heterozygous carriers. This mutation was distinct from previously reported DNAH1 mutations associated with MMAF and only affected the East Asian group. Furthermore, the variant DNAH1 protein could not be detected in spermatozoa by Western blot or immunofluorescence staining although DNAH1 mRNA was expressed in the spermatozoa. Scanning electron microscopy and transmission electron microscopy analysis showed the anomalies in sperm flagella morphology and ultrastructure in patients carrying this genetic variant. In conclusion, our results add to knowledge of the genetic pathogeny of MMAF and further confirmed the effectiveness of genetic screening in the diagnosis of MMAF.