Project description:Chronic, low-dose UV irradiation (UVR) leads to premature ageing of the skin characterised by wrinkles and loss of elasticity. Although the aged appearance of photoexposed skin may take years to manifest, the biochemical and molecular damage that underpins photoageing can occur following a single physiological dose of UVR. Understanding the damage mechanisms that are elicited in skin following acute UVR could help to inform strategies to delay photoageing. Targeted approaches show that UVR alters the abundance and structure of selected ECM proteins and protein assemblies, and these processes are driven by UV-induced reactive oxygen species (ROS). However, due to limitations in proteomic analysis, it has been difficult to evaluate the effects of acute UVR on an entire ECM-enriched proteome, containing hundreds of proteins. Peptide location fingerprinting (PLF) is a proteomic analysis tool that can identify structural changes in hundreds of proteins across different treatment groups using a non-targeted approach. The aim of this study was to use PLF to identify proteins within an ECM-enriched proteome that is structurally altered in response to UV. To
confirm the utility of PLF, structural changes in native type-I collagen, known to be UV-resistant, and purified human fibronectin, known to be UV susceptible, were evaluated following UVR at 50 mJ/cm2 and 500 mJ/cm2. Results show that native type-I collagen displays no significant structural changes in response to UVR, whereas UV irradiated human tissue fibronectin shows significant structural changes within the functional domains binding fibrin/heparin and collagen. Using a ECM-enriched proteome in vitro, PLF identifies 25 proteins from amongst a proteome of 977 proteins that show structural changes in response to acute UVR (100 mJ/cm2). The highly variable UV chromophore content among this group of 25 proteins suggests that abundance of UV chromophores alone cannot account for the structural changes observed in response to UVR. Protein interaction analysis (STRING) shows that UV targeted proteins are involved in collagen fibril formation, glycosaminoglycan metabolism and protein translation, and assessment of protein domain organization (Uniprot) shows that acute UV alters domains involved in ECM binding (COL5A1, versican) and myosin motility. In conclusion, this study identifies a select group of extracellular and intracellular dermal proteins that are susceptible to acute UVR and identifies the specific protein domains in which acute UV-mediated damage occurs.
Project description:Ultraviolet radiation (UVR) is a major environmental stressor for terrestrial plants. Here we investigated genetic responses to acute broadband UVR exposure in the highly desiccation-tolerant mosses Syntrichia caninervis and Syntrichia ruralis, using a comparative transcriptomics approach. We explored whether UVR protection is physiologically plastic and induced by UVR exposure, addressing the following questions: (1) What is the timeline of changes in the transcriptome with acute UVR exposure in these two species? (2) What genes are involved in the UVR response? and (3) How do the two species differ in their transcriptomic response to UVR? There were remarkable differences between the two species after 10 and 30 min of UVR exposure, including no overlap in significantly differentially abundant transcripts (DATs) after 10 min of UVR exposure and more than twice as many DATs for S. caninervis as there were for S. ruralis. Photosynthesis-related transcripts were involved in the response of S. ruralis to UVR, while membrane-related transcripts were indicated in the response of S. caninervis. In both species, transcripts involved in oxidative stress and those important for desiccation tolerance (such as late embryogenesis abundant genes and early light-inducible protein genes) were involved in response to UVR, suggesting possible roles in UVR tolerance and cross-talk with desiccation tolerance in these species. The results of this study suggest potential UVR-induced responses that may have roles outside of UVR tolerance, and that the response to URV is different in these two species, perhaps a reflection of adaptation to different environmental conditions.
Project description:Bone tissue is comprised of collagen, non-collagenous proteins, and hydroxyapatite and the SIBLING (small integrin binding, N-linked glycoprotein) family of proteins is the primary group of non-collagenous proteins. By replicating the native interactions between collagen and the SIBLING proteins at the interface of an implant, it is believed that a bone scaffold will more easily integrate with the surrounding tissue. In this work, bone sialoprotein, osteopontin (OPN), dentin sialoprotein (DSP), dentin phosphoprotein (DPP), C-terminal fragment of dentin matrix protein 1 (DMP1-C), and proteoglycan versions of DSP (DSP-PG) and DMP1 (DMP1-PG) were tested individually to determine their roles in collagen fibrillogenesis and the prevention of denaturation. It was shown that DSP and DPP slowed down fibrillogenesis, while other SIBLINGs had limited impact. In addition, the denaturation time was faster in the presence of DSP and OPN, indicating a negative impact. The role of calcium ions in these processes was also investigated. The presence of calcium ions sped up fibrillogenesis in all scenarios tested, but it had a negative impact by reducing the extent. Calcium also sped up the denaturation in most cases, with the exception of DMP1-C and DSP where the opposite was seen. Calcium had a similar effect on the proteoglycan variants in the fibrillogenesis process, but had no impact on the denaturation process in the presence of these two. It is believed that incorporating DMP1-C or DSP on the surface of a bone implant may improve the collagen interactions with the implant, thereby facilitating improved osteointegration.
Project description:Cannabis cultivation and processing is becoming an important industry in the United States and Canada. The industry employs over 400,000 workers in the United States and is growing rapidly. Both natural sunlight and artificial lamp-generated radiation are commonly used to grow cannabis plants. These optical sources can contain both visible and ultraviolet radiation (UVR) wavelengths, and overexposure to UVR is associated with negative health effects. The severity of these adverse health effects is governed by the specific wavelengths and exposed dose of UVR, yet worker exposure to UVR within cannabis-growing facilities has not been studied. In this study, worker exposure to UVR was assessed at five cannabis production facilities in Washington State, including indoor, outdoor, and shade house facilities. Lamp emission testing was performed at each facility and worker UVR exposures were measured for 87 work shifts. Observations of worker activities and use of personal protective equipment in association with UVR exposure measurements were recorded. For lamp emission measurements, at 3 feet from the center of the lamp, the average irradiances were 4.09 × 10-4, 6.95 × 10-8, 6.76 × 10-9, 3.96 × 10-9, and 1.98 × 10-9 effective W/cm2 for germicidal lamps, metal halide lamps, high-pressure sodium lamps, fluorescent lamps, and light emitting diodes, respectively. The average measured UVR exposure was 2.91 × 10-3 effective J/cm2 (range: 1.54 × 10-6, 1.57 × 10-2 effective J/cm2). Thirty percent of the work shifts monitored exceeded the American Conference for Governmental Industrial Hygienists (ACGIH®) threshold limit value (TLV®) of 0.003 effective J/cm2. Exposures were highest for workers who spent all or part of the work shift outdoors, and solar radiation was the primary source of worker UVR exposure for most of the work shifts that exceeded the TLVs. Outdoor workers can reduce UVR exposure by applying sunscreen and wearing appropriate personal protective equipment. Although the artificial lighting used in the cannabis production facilities included in this study did not contribute substantially to the measured UV exposures, in many cases the lamp emissions would generate theoretical exposures at 3 feet from the center of the lamp that would exceed the TLV. Therefore, employers should choose low UVR emitting lamps for indoor grow operations and should use engineering controls (e.g., door-interlocks to de-energize lamps) to prevent worker exposure to UVR from germicidal lamps.
Project description:One of the most robust examples of self-assembly in living organisms is the formation of collagen architectures. Collagen type I molecules are a crucial component of the extracellular matrix, where they self-assemble into fibrils of well-defined axial striped patterns. This striped fibrillar pattern is preserved across the animal kingdom and is important for the determination of cell phenotype, cell adhesion, and tissue regulation and signaling. The understanding of the physical processes that determine such a robust morphology of self-assembled collagen fibrils is currently almost completely missing. Here, we develop a minimal coarse-grained computational model to identify the physical principles of the assembly of collagen-mimetic molecules. We find that screened electrostatic interactions can drive the formation of collagen-like filaments of well-defined striped morphologies. The fibril axial pattern is determined solely by the distribution of charges on the molecule and is robust to the changes in protein concentration, monomer rigidity, and environmental conditions. We show that the striped fibrillar pattern cannot be easily predicted from the interactions between two monomers but is an emergent result of multibody interactions. Our results can help address collagen remodeling in diseases and aging and guide the design of collagen scaffolds for biotechnological applications.
Project description:The complex interplay between ultraviolet radiation (UVR) and cutaneous viral infections in the context of cancer etiology is challenging to unravel, given the limited information on the independent association between UVR and cutaneous viral infections. Using multiple biomarkers of infection with 24 types of cutaneous human papillomavirus (HPV) and 4 types of polyomaviruses (HPyV), we investigated cross-sectional associations with recent UVR exposure, using skin pigmentation measured by spectrophotometer. Age- and sex-adjusted associations between UVR and viral seropositivity, viral DNA present in eyebrow hairs (EBH) and skin swabs (SSW) were estimated using logistic regression. Beta-HPV seropositivity was associated with viral DNA positivity in EBH (OR = 1.40, 95% CI = 1.05-1.88) and SSW (OR = 1.86, 95% CI = 1.25-2.74). Similar associations were observed for Merkel cell polyomavirus. Participants in the highest tertile of UVR exposure were more likely to be seropositive for beta-HPV (OR = 1.81, 95% CI = 1.16-2.38), and have beta-HPV DNA in EBH (OR = 1.57, 95% CI = 1.06-2.33) and SSW (OR = 2.22, 95% CI = 1.25-3.96), compared to participants with the lowest tertile of UVR exposure. UVR exposure was positively associated with three different markers of beta-HPV infection. Therefore, future studies of HPV associated KC development should address more directly the role of HPV and UVR exposure as potential co-carcinogens.
Project description:Collagen deposition contributes to both high mammographic density and breast cancer progression. Low stromal PTEN expression has been observed in as many as half of breast tumors and is associated with increases in collagen deposition, however the mechanism connecting PTEN loss to increased collagen deposition remains unclear. Here, we demonstrate that Pten knockout in fibroblasts using an Fsp-Cre;PtenloxP/loxP mouse model increases collagen fiber number and fiber size within the mammary gland. Pten knockout additionally upregulated Sparc transcription in fibroblasts and promoted collagen shuttling out of the cell. Interestingly, SPARC mRNA expression was observed to be significantly elevated in the tumor stroma as compared to the normal breast in several patient cohorts. While SPARC knockdown via shRNA did not affect collagen shuttling, it notably decreased assembly of exogenous collagen. In addition, SPARC knockdown decreased fibronectin assembly and alignment of the extracellular matrix in an in vitro fibroblast-derived matrix model. Overall, these data indicate upregulation of SPARC is a mechanism by which PTEN regulates collagen deposition in the mammary gland stroma.
Project description:Collagen, the most abundant protein in mammals, is able to form fibrils, which have central role in tissue repair, fibrosis, and tumor invasion. As a component of skin, tendons, and cartilages, this protein contacts with any implanted materials. An inherent problem associated with implanted prostheses is their propensity to be coated with host proteins shortly after implantation. Also, silicone implants undergoing relatively long periods of contact with blood can lead to formation of thrombi and emboli. In this paper, we demonstrate the existence of interactions between siloxanes and collagen. Low-molecular-weight cyclic siloxane (hexamethylcyclotrisiloxane-D3) and polydimethylsiloxanes (PDMS) forming linear chains, ranging in viscosity from 20 to 12,000 cSt, were analyzed. We show that D3 as well as short-chain PDMS interact with collagen, resulting in a decrease in fibrillogenesis. However, loss of collagen native structure does not occur because of these interactions. Rather, collagen seems to be sequestered in its native form in an interlayer formed by collagen-siloxane complexes. On the other hand, silicone molecules with longer chains (i.e., PDMS with viscosity of 1000 and 12,000 cSt, the highest viscosity analyzed here) demonstrate little interaction with this protein and do not seem to affect collagen activity.
Project description:ObjectivesJob exposure matrices (JEMs) are important tools for estimating occupational exposures in study populations where only information on industry and occupation (I&O) are available. JEMs The objective of this work was to create JEMs for solar and artificial ultraviolet radiation (UVR) using a US standardized coding scheme.MethodsUsing U.S. Census Bureau industry and occupation codes, separate lists of I&O pairs were developed for solar and artificial UVR by a panel of Certified Industrial Hygienists who assigned exposure ratings to I&O pairs with potential exposure. Parameters for exposure included prevalence (P) and frequency (F) for solar UVR and P, F, and intensity (I) for artificial UVR. Prevalence, or percent of all workers employed in an I&O pair who were exposed, was categorically rated: 0 to <1, 1 to <20; 20 to <80, and ≥80. Frequency of exposure, defined by the number of hours per week workers were exposed, was categorically rated: 0 to <5, 5 to <20, 20 to <35, and ≥35 h per week. For artificial UVR only, intensity of exposure was assigned three ratings: low, low with rare excursions, and >low under normal conditions. Discrepant ratings were resolved via consensus.ResultsAfter excluding I&O pairs assigned P and F ratings of 0 (solar UVR) and P, F, and I ratings of 0 (artificial UVR) from the JEM, 9206 I&O pairs were rated for solar UVR and 2010 I&O pairs for artificial UVR. For solar UVR, 723 (7.9% of all rated pairs) had ratings in the highest category for P and F; this group included 45 occupations in varied industries. Construction and extraction occupations represented most of the occupations (n = 20; 44%), followed by farming, fishing, and forestry occupations (n = 6; 13%). For artificial UVR, 87 I&O pairs (4.3% of all rated pairs) had maximum ratings for P, F, and I; these comprised a single occupation (welding, soldering, and brazing workers) in diverse industries.ConclusionsJEMs for solar and artificial UVR were developed for a broad range of I&O pairs in the US population and are available for use by researchers conducting occupational epidemiological studies.
Project description:The extracellular matrix (ECM) is a complex mixture composed of fibrillar collagens as well as additional protein and carbohydrate components. Proteoglycans (PGs) contribute to the heterogeneity of the ECM and play an important role in its structure and function. While the small leucine rich proteoglycans (SLRPs), including decorin and lumican, have been studied extensively as mediators of collagen fibrillogenesis and organization, the function of large matrix PGs in collagen matrices is less well known. In this study, we showed that different matrix PGs have distinct roles in regulating collagen behaviors. We found that versican, a large chondroitin sulfate PG, promotes collagen fibrillogenesis in a turbidity assay and upregulates cell-mediated collagen compaction and reorganization, whereas aggrecan, a structurally-similar large PG, has different and often opposing effects on collagen. Compared to versican, decorin and lumican also have distinct functions in regulating collagen behaviors. The different ways in which matrix PGs interact with collagen have important implications for understanding the role of the ECM in diseases such as fibrosis and cancer, and suggest that matrix PGs are potential therapeutic targets.