Rapamycin protects mouse skin from ultraviolet B-induced photodamage by modulating Hspb2-mediated autophagy and apoptosis

BACKGROUND

Continuous exposure to UVB is the main extrinsic cause of skin photodamage, which is associated with oxidative stress, DNA damage, apoptosis and degradation of collagen. Rapamycin, a mechanistic target inhibitor of rapamycin complex 1 (mTORC1), has been shown to play a crucial role anti-tumor and aging retardation, but its mechanism of action in UVB-induced photodamage still remains unknown. In this study, we investigated the role of rapamycin and Hspb2 (also known as Hsp27) in UVB-induced photodamage in mice.

METHODS AND RESULTS

We constructed skin acute photodamage models on the ears of WT and Hspb2 KO mice, respectively, and administered rapamycin treatment. Histological results showed that knockout of the hspb2 exacerbated the skin damage, as evidenced by thickening of the epidermis, breakage and disruption of collagen fibers and reduction in their number, which is reversed by rapamycin treatment. In addition, hspb2 knockout promoted UVB-induced apoptosis and reduced autophagy levels, with a significant increase in p53 levels and Bax/Bcl-2 ratio, a reduction in LC3II/I ratio and an increase in p62 levels in the KO mice compared to those in WT mice after the same dose of UVB irradiation. Rapamycin was also found to inhibit collagen degradation induced by hspb2 knockdown through activation of the TGF-β/Smad signaling pathway.

CONCLUSIONS

Rapamycin can alleviate skin photodamage from Hspb2 knockout to some extent. It may be a potential therapeutic drug for skin photodamage. In this study, we investigated the role of rapamycin and Hspb2 in UVB-induced photodamage in mice. Histological results showed that knockout of the hspb2 exacerbated the skin damage, as evidenced by thickening of the epidermis, breakage and disruption of collagen fibers and reduction in their number, which is reversed by rapamycin treatment. In addition, hspb2 knockout promoted UVB-induced apoptosis and reduced autophagy levels. Rapamycin was also found to inhibit collagen degradation induced by hspb2 knockdown through activation of the TGF-β/Smad signaling pathway. We conclude that rapamycin and Hspb2 exert a synergistic protective effect in skin photodamage.

Predicting the Risk of Nail Involvement in Psoriasis Patients: Development and Assessment of a Predictive Nomogram

BACKGROUND

Nail involvement has a tremendous impact on psoriasis patients. Early detection and prompt intervention of psoriatic nail damage are necessary.

METHODS

A total of 4290 patients confirmed to have psoriasis between June 2020 and September 2021 were recruited from the Follow-up Study of Psoriasis database. Among them, 3920 patients were selected and divided into the nail involvement group (n = 929) and the non-nail involvement group (n = 2991) by inclusion and exclusion criteria. Univariate and multivariable logistic regression analyses were performed to identify the predictors of nail involvement for the nomogram. Calibration plots, the receiver operating characteristic (ROC) curve, and decision curve analysis (DCA) were used to evaluate the discriminative and calibrating ability and clinical utility of the nomogram.

RESULTS

Sex, age at onset, duration, smoking, drug allergy history, comorbidity, sub-type of psoriasis, scalp involvement, palmoplantar involvement, genital involvement, and PASI score were selected to establish the nomogram for nail involvement. AUROC (0.745; 95% CI: 0.725-0.765) indicated the satisfactory discriminative ability of the nomogram. The calibration curve showed favorable consistency, and the DCA showed the good clinical utility of the nomogram.

CONCLUSION

A predictive nomogram with good clinical utility was developed to assist clinicians in evaluating the risk of nail involvement in psoriasis patients.

HSP27 Protects Skin From Ultraviolet B -Induced Photodamage by Regulating Autophagy and Reactive Oxygen Species Production

Ultraviolet (UV) irradiation has been well documented to be linked with almost all skin problems we know, and both dermis and epidermis may be affected to varying degrees by UV irradiation. Every time when exposed to sunlight without protection, our skin will step closer to photoaging, leading to irreversible consequences ultimately. Heat shock protein 27 (HSP27) is a vital protein involved in cell growth, autophagy, apoptosis, drug resistance, tumor genesis and metastasis. Evidence suggests that the organism is subjected to various internal and external environmental stresses (heat, oxidative stress, organic toxicants, etc.), and HSP27 with high expression has protective function. However, the expression of HSP27 in coping with UV irradiation have not been examined thoroughly. In this study, photodamage models were developed through different doses of UVB irradiation in human epidermal keratinocytes (HEKs) (30 mJ/cm²), human dermal fibroblasts (HDFs) (150 mJ/cm²) and mouse skin (2,700 mJ/cm²). HSP27 knockdown decreased cell viability and increased the incidence of UVB-induced reactive oxygen species (ROS) production. We got consistent results in vivo and vitro. Compared with that in the UVB group, the expression of LC3B was significantly lower, while the expression of p62 was significantly higher in the UVB + si-HSP27 group. It was also revealed that HSP27 knockdown reduced the expressions of some antioxidants, such as superoxide dismutase (SOD) and catalase (CAT), which accelerated UVB-induced ROS release. Moreover, histological results showed that epidermis was thickened and collagen fibers were disorganized in the UVB + si-HSP27 group. These findings have demonstrated that HSP27 might play a photoprotective role in the UVB-induced skin damage process by maintaining the normal autophagy and antioxidant level. It is implied that HSP27 could be a potential therapeutic target of photodamage. However, determination of the definitive mechanism requires further exploration.

Sulfated polysaccharides and immune response: promoter or inhibitor?

Sulfated polysaccharides, which frequently connect to core protein, are expressed not only on cell surface but also throughout the extracellular matrix. Besides providing structural integrity of cells, sulfated polysaccharides interact with a variety of sulfated polysaccharides-binding proteins, such as growth factors, cytokines, chemokines and proteases. Sulfated polysaccharides play two-edged roles, inhibitor and promoter, in immune response. Some sulfated polysaccharides act as the immunosuppressor by blocking inflammatory signal transduction induced by proinflammatory cytokines, suppressing the activation of complement and inhibiting the process that leukocytes adhere to and pass through endothelium. On the contrary, the interaction between immune cells and sulfated polysaccharides produced by bacteria, endothelial cells and immune cells initiate the occurrence of immune response. It promotes the processes of recognizing and arresting antigen, migrating transendothelium, moving into and out of immune organ and enhancing the proliferation of lymphocyte. The structure of sulfated polysaccharides, such as molecular weight and sulfated sites heterogeneity, especially the degree of disaccharide sulfation, position of the sulfate moiety and organization of sulfated domains, may play critical role in their controversial effects. As a consequence, the interaction between sulfated polysaccharides and sulfated polysaccharide-binding proteins may be changed by modifying the structure of sulfated polysaccharides chains. The administration of drug targeting sulfated polysaccharide-protein interaction may be useful in treating inflammatory related diseases.

Changes of biophysical behavior of k562 cells for p16 gene transfer

p16 gene was transferred into human erythroleukemia cell line K562 that had been subjected to p16 deletion. The changes of biophysical behavior of K562 cells after gene transfer were studied with the micropipette technique. The micropipette data were analyzed with a standard solid viscoelastic model. In comparison to untransfected control K562 cells and the cells transfected with an empty vector, the p16-transfected K562 cells showed an increase in the elastic element K(1), which is inversely proportional to the maximum deformation over a long period of time, whereas the viscous element mu and the other elastic element K(2) showed no significant difference. The results indicate that K562 cells became more rigid after p16 transfer. The p16-transfected K562 cells also had a higher surface charge density. This study contributes to our knowledge about the suppression effect of p16 gene on tumor cell migration and about its use in gene therapy.

Public awareness of stuttering in Shanghai, China

This study reports the results of an investigation of knowledge and public awareness of stuttering among laypersons in Shanghai, China. A total number of 1968 respondents answered a questionnaire including questions about prevalence, onset, gender distribution and occurrence in different cultures, cause, treatment, intelligence and heredity of stuttering. Stuttering appears to be a disorder that most people in the Shanghai area are familiar with, and for several aspects a considerable number of respondents held views that are in line with current knowledge about stuttering. For some aspects though knowledge is limited, indicating a need for disseminating scientific information on stuttering. The results of the present study are compared with a similar Belgium study.

Application of statistically-based experimental designs for the optimization of eicosapentaenoic acid production by the diatom Nitzschia laevis

Statistically based experimental designs were applied to the optimization of medium components and environmental factors for eicosapentaenoic acid (EPA) production by the diatom Nitzschia laevis in heterotrophic conditions. First, the Plackett-Burman design was used to evaluate the effects of variables including medium components and environmental factors on cell growth and EPA production. Among these variables, NaCl, CaCl(2), PI metal solution, pH, and temperature were identified to have the significant effects (with confidence level > 90 %). Subsequently, the concentrations of NaCl, CaCl(2), PI metal solution as well as the values of pH and temperature were optimized using central composite design. The cell growth and EPA production were found to respectively correlate to NaCl, CaCl(2), pH, and temperature that could be represented by second-order polynomial models. The optimal values of the four parameters were determined by response surface and numerical analyses as 8 g/L NaCl, 0.10 g/L CaCl(2), pH 8.5 and 19.8 degrees C for cell dry weight (DW), and 14 g/L NaCl, 0.10 g/L CaCl(2), pH 8.5 and 18 degrees C for EPA production, respectively. The subsequent verification experiments confirmed the validity of the models. This optimization strategy led to a DW of 9 g/L, an EPA yield of 280 mg/L and an EPA productivity of 28 mg/L/d, respectively, which were considerably higher than those obtained in the previous studies.

A perfusion-cell bleeding culture strategy for enhancing the productivity of eicosapentaenoic acid by Nitzschia laevis

A perfusion-cell bleeding culture strategy was developed for enhancing the productivity of eicosapentaenoic acid (EPA) by the diatom Nitzschia laevis. As the strategy combined the concepts of continuous culture and perfusion culture, it allowed continuously and simultaneously harvesting the algal cells and removing inhibitory compounds during the cultivation. Compared with a single operation of continuous culture, the perfusion-cell bleeding culture greatly enhanced the steady-state biomass concentration, biomass productivity, EPA yield, EPA productivity and glucose utilization efficiency. The perfusion-cell bleeding culture also allowed higher biomass productivity and EPA productivity than the single perfusion culture did. At a bleeding rate of 0.67 day(-1) and a perfusion rate of 0.6 day(-1), the EPA productivity achieved 175 mg l(-1) day(-1), which is the highest ever reported in microalgal cultures.

The POU homeodomain protein Oct-1 binds Cis-regulatory element essential for the human GnRH upstream promoter activity in JEG-3 cells

In previous studies, we have localized four specific nuclear protein-binding elements in the human GnRH upstream promoter. To test whether these four elements are reproductive tissue specific, we placed the four elements upstream to a thymidine kinase (TK) promoter/luciferase reporter gene, and transfected the constructs into human placental choriocarcinoma (JEG-3) cells. The 272-bp fragment (-994 to -723) containing the four elements can drive heterologous TK promoter expression in JEG-3 cells about 15 times more than that of basal TK promoter activity. Deletion of element 4 (E4, -987/-968) significantly decreased (4-fold) the luciferase activity. Further deletion of the other elements (E3 individual, -960/-940 or E3 and E2 in combination, -919/-896) only slightly decreased the luciferase activity. In contrast, deletion of element 1 (E1, -876/-851) caused a 2-fold loss of luciferase activity and elimination of E2 and E3 only lost less than 2-fold of the luciferase activity. Study performed with 5' end deletion of this region confirmed these observations. Furthermore, E4 DNA-protein complex can be supershifted by Oct-1 antibody, indicating that Oct-1 binds to E4. These results clearly demonstrated that all four elements are required to confer tissue-specific expression of the hGnRH gene in JEG-3 cells. However, the E4 is the most important for the tissue-specific expression of the hGnRH gene in JEG-3 cells. Oct-1 factor binds with E4 element and may be involved in the mediation of the human GnRH upstream promoter activity.

[Tissue culture induced translocation conferring powdery mildew resistance between wheat and Dasypyrum villosum and its marker-assisted selection]

Glutamate oxaloacetate transaminase (GOT) electrophoretic analyses were performed in 175 regenerants arising from immature embryos of crosses between wheat (Triticum aestivum L.) and 6D/6V substitution stocks. The GOT-V2 coding specific enzyme band was absent in two regenerants, designated 98R149 and 98R159 respectively, originated from cross of Yi 4095 and 6D/6V substitution stock c.v. RW15. Pm21 gene linked SCARs (Sequence Characterized Amplified Regions) analysis indicated that 6VS chromosome arms existed in 98R149 and 98R159. Fluorescence in situ hybridization with total genomic DNA extracted from Dasypyrum villosum (L.) as a probe confirmed the occurrence of translocation between 6V chromosome and a wheat one in the two regenerants mentioned above. 98R149 and 98R159 were immune to powdery mildew (Erysiphe graminisDC. f. sp. tritici) inoculation with mix races collected from Hebei Province. The results of the present paper added another feasible example of useful translocations via tissue culture.

Effects of morphine on rheological properties of rat red blood cells

To evaluate the effect of morphine on red blood cells, in vivo and in vitro rat models of morphine dependence were established. Rheological properties of rat red cells were measured by ektacytometry; the biophysical changes in the membrane of rat red cells were measured by the Fourier-Transformed Infrared technique (FT-IR) and the fluorescence depolarization method. The results show that the membrane fluidity of red cells was greatly reduced by morphine and the secondary structure of membrane proteins was changed. This suggests that morphine affects the rat red cell membrane directly, rather than through opioids-receptors.

A novel perfusion system for animal cell cultures by two step sequential sedimentation

A novel perfusion system was developed for high density culture of animal cells. The system consists of an airlift bioreactor, a setting tank and a flat settler. Both the settling tank and flat settler have two connecting pipes for transporting the cells from and back to the reactor, respectively. Thus, the cell flow in the settlers can be controlled in uni-direction, avoiding the countercurrent flow of the cells. During perfusion cultures, the cells firstly settled in the settling tank, then, unsettled cells in the tank were transferred to the flat settler for re-settling. With the application of the system to hybridoma cell cultures, it was found that the maximum viable cell density, monoclonal antibody concentration and average productivity were 1.31 x 107 cells ml-1, 400 mg l-1 and 461 mg l-1 d-1, respectively, which were much higher than those of a batch culture. Both theoretical analysis and experimental results showed a much higher separation efficiency in such a two-step sedimentation system than that in a conventional one-step sedimentation system. In addition, the volumetric ratio of the sedimentation devices to the culture volume in our developed system is much lower, which may be potentially useful on an industrial-scale.

An animal model to study erythrocyte senescence with a narrow time window of erythrocyte production: alterations in osmotic fragility and deformability of erythrocytes during their life span

Using the model in which the entire RBC population was nearly synchronously produced following the induction of spherocytic anemia in the rabbit with antibody serum, we determined the changes of RBC osmotic fragility and deformability with aging. The results showed that the osmotic fragility increased with the RBC aging process in a nonlinear manner, being much more profound in the later part of the RBC life span. The RBC deformation index (DI) was measured by an ektacytometry. It is found that the DI decreased with RBC aging in a nonlinear fashion, with increasingly greater changes in the later part of the RBC life span. The alterations of RBC mechanical properties with aging may be attributable to a number of factors, including changes of RBC size and shape, and the viscoelasticity of the cytoplasm and membrane.

An animal model to study erythrocyte senescence with a narrow time window of erythrocyte production

Using the method of inducing spherocytic anemia in the rabbit with antibody serum, we have developed an animal model in which red blood cells (RBCs) can nearly grow synchronously. With this model, we determined that the surface charge density on the RBC membrane decreased with cell aging. The change was not linear, being much more profound in the latter half of RBC life span. There was a positive correlation between the mean RBC density and its "age" (r = 0.847, p < 0.01). However, the density distribution of the RBCs at the same "age" showed a broad range, and the density values for RBC groups with different ages showed considerable overlap. This indicates that the density gradient technique can be used to separate RBC population into fractions with different mean ages, but has a low resolving power for obtaining individual RBCs of a given "age".

A study of effects of WGA and ConA on RBC membrane receptors using a new ektacytometric method

With a new ektacytometry, we studied the relation between the microstructure of red blood cell (RBC) membrane and the rheological properties of RBCs in a shear flow field of low viscosity. The main contributions of this paper are as follows: 1. The hemorheological meanings of the orientation index (DI)or and the small deformation index (DI)d were explored. (DI)or is an overall rheological index depending on the deformability and morphology of RBCs. The better the physiological shape of RBCs is maintained, the greater the (DI)or is. (DI)d can be used to describe the lipid fluidity of RBC membrane. Such an explanation for the meaning of (DI)d has been forcefully supported by our experiments using electron spin resonance (ESR) and fluorescence polarization. 2. The influence of wheat germ agglutinin (WGA) of different concentrations on the lipid fluidity of membrane is different from that of concanavalin A (ConA). The lipid fluidity of membrane changes with WGA concentration treating RBCs and there is a maximum value for the membrane fluidity at a specific concentration of WGA. However, the deformability of membrane described by the integrate deformation index (IDI) monotonically decreased with the increase in WGA concentration treating RBCs. 3. It is concluded that the increase in the lipid fluidity of red cell membrane is not necessarily associated with the improvement of RBC deformability.

[A clinical study on the effect of kaisailu on alleviating neonatal jaundice]

The effects of kaisailu defecation on alleviating neonatal jaundice were studied. 203 case of newborns fed with total mother breast milk were divided into two groups: experimental group (100 cases) received routine treatment and kaisailu (10 ml per rectum) control group (103 cases) only received routine treatment. The findings were as follows: excretory time of meconium in experimental group was more ahead than that in control group; the excretory meconium volume of the first time was obviously higher in experimental group; time of meconium changed yellow was distinctly shorter and the bilirubin index (measured by transcortical bilirubin method) lowered more rapidly in experimental group than that in control group. The results suggested that kaisailu defecation can alleviate neonatal jaundice.

A study of RBC aggregation-sedimentation phenomenon with conductivity method

In this paper, we present a conductivity method for measuring the RBC (red blood cell) aggregation-sedimentation phenomenon and the theoretical analysis of this phenomenon. A theory describing the RBC aggregation-sedimentation phenomenon with the conductivity method is proposed and the formula of the l-t function which depicts the RBC aggregation-sedimentation process is given. We put forward the aggregation index and sedimentation factor describing the RBC aggregation-sedimentation phenomenon for the first time.

[On the relation between substance P and physostigmine on cardiovascular control in rabbit brain]

Using an electromagnetic flowmeter technique, the cardiac output as measured by blood flow in the aortic arch was measured during intracerebroventricular injection (icv.) of Substance P (SP) and physostigmine in 47 anesthetized rabbits. Carotid artery blood pressure and heart rate were recorded. After icv of SP (20 micrograms/20 microliters) or physostigmine (60 micrograms/20 microliters), both cardiac output and mean artery pressure were increased. Pretreatment with icv. of atropine (150 micrograms/20 microliters) did not alter the effect of SP, but the effect of physostigmine was blocked by pretreatment with SP blocker (25 micrograms/20 microliters). These findings suggest that cerebral SP is involved in cholinergic mechanisms on the central control of blood pressure.