Down-regulation of tissue inhibitor of matrix metalloprotease-1 (TIMP-1) in aged human skin contributes to matrix degradation and impaired cell growth and survival

Wound treatment with curcumin prevents hypertrophic scarring and promotes remodeling by inhibiting fibroblast activation and regulating collagen deposition

More and more attention is paid to the prevention of hypertrophic scars (HS). This study aimed to investigate the mechanisms of topical curcumin application in alleviating HS secondary to wounds. Human dermal fibroblasts (HDFs) were cultured with transforming growth factor-β1 and varying concentrations of curcumin for 48 h. The proliferation activity, apoptosis and migration of HDFs were detected by CCK-8 assay, EdU assay, flow cytometry and wound healing assay, respectively. The expression of proteins implicated in fibroblast activation and collagen deposition was determined by Western blotting (WB). Curcumin (25 μmol/L, 28 days) was applied to rabbit ear wounds, and hypertrophic scarring was evaluated grossly and microscopically. We found that curcumin inhibited the proliferation and migration of HDFs and promoted cell apoptosis in a concentration-dependent manner. Curcumin at 10 and 25 μmol/L concentrations reduced the expression of Ki-67 and α-smooth muscle actin and increased cleaved caspase-3 expression and Bax/Bcl-2 ratio. Although the protein levels of collagen-I (COL-I), COL-III, matrix metalloproteinase-2 (MMP-2) and tissue inhibitor of metalloproteinase-1 (TIMP-1) were down-regulated, COL-III/COL-I and MMP-2/TIMP-1 ratios were maintained. Curcumin decreased the Manchester scar scale score, scar elevation index and collagen volume fraction of rabbit ear scars. Immunohistochemical results were generally consistent with the WB data. Unlike suppression of TIMP-1 in the entire region of the scar, curcumin reduced MMP-2 expression only in the edge part, which might be related to the alteration of cell polarity and orientation of fibroblasts. In conclusion, curcumin facilitates high-quality scars after wound healing by regulating fibroblast activation and collagen deposition.

Relationship Between Epidermal Matrix Metalloproteinase-1 and Dermal Collagen Reduction in Skin Subjected to Chronic Sun Exposure

Background/Objectives: Temporary decreases in dermal collagen caused by artificial ultraviolet exposure are largely affected by increased epidermis-derived matrix metalloproteinase (MMP)-1 levels. However, the role of epidermal MMP-1 in dermal tissue remodeling induced by chronic sun exposure remains unclear. This study aimed to clarify the involvement of epidermal and dermal MMP-1 in dermal collagen reduction induced by chronic sun exposure. Methods: Immunofluorescent staining of 30 facial skin tissue samples was performed to visualize MMP-1. The fluorescence intensity of epidermal MMP-1 observed on microscopic images was analyzed in relation to the severity of dermal tissue remodeling and the dermal collagen fiber density. A similar correlation analysis of the number of dermal MMP-1-positive cells was also performed. Results: Epidermal MMP-1 was observed in the stratum spinosum of skin without severe tissue remodeling; however, in skin with severe dermal tissue remodeling, MMP-1 was localized throughout the epidermis. The epidermal MMP-1 signal area and dermal collagen fiber density were negatively correlated (ρ = -0.383; p = 0.0002; n = 90). However, the ratio of dermal MMP-1-positive cells to total dermal cells was only negatively correlated with the collagen fiber density in skin that was not severely remodeled (ρ = -0.746; p = 0.001; n = 15). Conclusions: Epidermal MMP-1 is involved in the tissue remodeling of skin that is subjected to chronic sun exposure and short-term ultraviolet radiation exposure. However, dermal-cell-derived MMP-1 may be involved in biological processes that require an immediate collagen degradation response. The results of this study demonstrate the importance of controlling epidermal MMP-1 to inhibit dermal tissue remodeling induced by chronic sun exposure and provide new insights that are beneficial to the development of anti-photoaging skincare cosmetics.

Impact of Vitamin D on Skin Aging, and Age-Related Dermatological Conditions

Human skin is a physical and biochemical barrier that protects the internal body from the external environment. Throughout a person's life, the skin undergoes both intrinsic and extrinsic aging, leading to microscopic and macroscopic changes in its morphology. In addition, the repair processes slow with aging, making the older population more susceptible to skin diseases. Intrinsic factors associated with advanced age gradually degrade the dermal collagen matrix, resulting in fine wrinkles and reduced elasticity; this is accelerated in post-menopausal women due to estrogen deficiency. In contrast, extrinsic factors associated with advanced age, primarily caused by exposure to ultraviolet (UV) radiation, lead to coarse wrinkles, solar elastosis, hyperkeratosis, irregular pigmentation, and skin cancers. UVB radiation, while contributing to skin photo-aging, also induces the cutaneous synthesis of vitamin D. Vitamin D, in turn, protects the skin from oxidative stress, inflammation, and DNA damage, thereby delaying both chronological and photo-aging. Moreover, research has demonstrated an association between lower vitamin D levels and a higher prevalence of certain cutaneous diseases. This review explores and summarizes the critical role of vitamin D in skin aging and age-related skin diseases. The data presented highlight the importance of maintaining vitamin D adequacy throughout life.

Extracellular vesicles from human urine-derived stem cells delay aging through the transfer of PLAU and TIMP1

Aging increases the risks of various diseases and the vulnerability to death. Cellular senescence is a hallmark of aging that contributes greatly to aging and aging-related diseases. This study demonstrates that extracellular vesicles from human urine-derived stem cells (USC-EVs) efficiently inhibit cellular senescence in vitro and in vivo. The intravenous injection of USC-EVs improves cognitive function, increases physical fitness and bone quality, and alleviates aging-related structural changes in different organs of senescence-accelerated mice and natural aging mice. The anti-aging effects of USC-EVs are not obviously affected by the USC donors' ages, genders, or health status. Proteomic analysis reveals that USC-EVs are enriched with plasminogen activator urokinase (PLAU) and tissue inhibitor of metalloproteinases 1 (TIMP1). These two proteins contribute importantly to the anti-senescent effects of USC-EVs associated with the inhibition of matrix metalloproteinases, cyclin-dependent kinase inhibitor 2A (P16INK4a), and cyclin-dependent kinase inhibitor 1A (P21cip1). These findings suggest a great potential of autologous USC-EVs as a promising anti-aging agent by transferring PLAU and TIMP1 proteins.

Osteoporosis and dermatoporosis: a review on the role of vitamin D

Osteoporosis (OP) and Dermatoporosis (DP) are expressions of the aging process at the skin and bone levels, respectively. Both conditions are associated with increased morbidity for elderly people, and this requires necessary interventions. They share many common risk factors; among these, vitamin D (VD) deficiency appears to have a role. VD is involved in either disease with many mechanisms, among which immunomodulation. VD deficiency has been linked to OP because it inhibits the body's capacity to absorb calcium and maintain optimal bone health. Available evidence suggests that proper vitaminosis D also appears to be vital in preventing skin age-related issues. DP is often seen in elderly individuals, particularly those with long-term sun exposure and a history of chronic sun damage. VD deficiency can be linked to DP, since its involvement in collagen production, epidermal barrier function, inflammation regulation, wound healing, and sun protection. Aim of this review is to summarize the most updated existing evidence on the role of VD in the development of fragility syndromes such as DP and OP and the possible benefits of VD supplementation as a simple and harmful weapon against aging.

Targeting Hydroxybenzoic Acids to Mitochondria as a Strategy to Delay Skin Ageing: An In Vitro Approach

Targeting antioxidants to mitochondria is considered a promising strategy to prevent cellular senescence and skin ageing. In this study, we investigate whether four hydroxybenzoic acid-based mitochondria-targeted antioxidants (MitoBENs, MB1-4) could be used as potential active ingredients to prevent senescence in skin cells. Firstly, we evaluated the chemical stability, cytotoxicity, genotoxicity and mitochondrial toxicity of all compounds. We followed this by testing the antioxidant protective capacity of the two less toxic compounds on human skin fibroblasts. We then assessed the effects of the best hit on senescence, inflammation and mitochondrial remodeling on a 3D skin cell model, while also testing its mutagenic potential. Cytotoxicity and mitochondrial toxicity rankings were produced: MB3 < MB4 ≃ MB1 < MB2 and MB3 < MB1 < MB4 < MB2, respectively. These results suggest that pyrogallol-based compounds (MB2 and MB4) have lower cytotoxicity. The pyrogallol derivative, MB2, containing a 6-carbon spacer, showed a more potent antioxidant protective activity against hydrogen peroxide cytotoxicity. In a 3D skin cell model, MB2 also decreased transcripts related to senescence. In sum, MB2’s biological safety profile, good chemical stability and lack of mutagenicity, combined with its anti-senescence effect, converts MB2 into a good candidate for further development as an active ingredient for skin anti-ageing products.

Bioreactors for Vocal Fold Tissue Engineering

It is estimated that almost one-third of the United States population will be affected by a vocal fold (VF) disorder during their lifespan. Promising therapies to treat VF injury and scarring are mostly centered on VF tissue engineering strategies such as the injection of engineered biomaterials and cell therapy. VF tissue engineering, however, is a challenging field as the biomechanical properties, structure, and composition of the VF tissue change upon exposure to mechanical stimulation. As a result, the development of long-term VF treatment strategies relies on the characterization of engineered tissues under a controlled mechanical environment. In this review, we highlight the importance of bioreactors as a powerful tool for VF tissue engineering with a focus on the current state of the art of bioreactors designed to mimic phonation in vitro. We discuss the influence of the phonatory environment on the development, function, injury, and healing of the VF tissue and its importance for the development of efficient therapeutic strategies. A concise and comprehensive overview of bioreactor designs, principles, operating parameters, and scalability are presented. An in-depth analysis of VF bioreactor data to date reveals that mechanical stimulation significantly influences cell viability and the expression of proinflammatory and profibrotic genes in vitro. Although the precision and accuracy of bioreactors contribute to generating reliable results, diverse gene expression profiles across the literature suggest that future efforts should focus on the standardization of bioreactor parameters to enable direct comparisons between studies. Impact statement We present a comprehensive review of bioreactors for vocal fold (VF) tissue engineering with a focus on the influence of the phonatory environment on the development, function, injury, and healing of the VFs and the importance of mimicking phonation on engineered VF tissues in vitro. Furthermore, we put forward a strong argument for the continued development of bioreactors in this area with an emphasis on the standardization of bioreactor designs, principles, operating parameters, and oscillatory regimes to enable comparisons between studies.

Identification and validation of pivotal genes related to age-related meniscus degeneration based on gene expression profiling analysis and in vivo and in vitro models detection

BACKGROUND

The componential and structural change in the meniscus with aging would increase the tissue vulnerability of the meniscus, which would induce meniscus tearing. Here, we investigated the molecular mechanism of age-related meniscus degeneration with gene expression profiling analysis, and validate pivotal genes in vivo and in vitro models.

METHODS

The GSE45233 dataset, including 6 elderly meniscus samples and 6 younger meniscus samples, was downloaded from the Gene Expression Omnibus (GEO) database. To screen the differential expression of mRNAs and identify the miRNAs targeting hub genes, we completed a series of bioinformatics analyses, including functional and pathway enrichment, protein-protein interaction network, hub genes screening, and construction of a lncRNA-miRNA-mRNA network. Furthermore, crucial genes were examined in human senescent menisci, mouse senescent meniscus tissues and mouse meniscus cells stimulated by IL-1β.

RESULTS

In total, the most significant 4 hub genes (RRM2, AURKB, CDK1, and TIMP1) and 5 miRNAs (hsa-miR-6810-5p, hsa-miR-4676-5p, hsa-miR-6877-5p, hsa-miR-8085, and hsa-miR-6133) that regulated such 4 hub genes, were finally identified. Moreover, these hub genes were decreased in meniscus cells in vitro and meniscus tissues in vivo, which indicated that hub genes were related to meniscus senescence and could serve as potential biomarkers for age-related meniscus tearing.

CONCLUSIONS

In short, the integrated analysis of gene expression profile, co-expression network, and models detection identified pivotal genes, which elucidated the possible molecular basis underlying the senescence meniscus and also provided prognosis clues for early-onset age-related meniscus tearing.

Alterations in extracellular matrix composition during aging and photoaging of the skin

Human skin is composed of the cell-rich epidermis, the extracellular matrix (ECM) rich dermis, and the hypodermis. Within the dermis, a dense network of ECM proteins provides structural support to the skin and regulates a wide variety of signaling pathways which govern cell proliferation and other critical processes. Both intrinsic aging, which occurs steadily over time, and extrinsic aging (photoaging), which occurs as a result of external insults such as solar radiation, cause alterations to the dermal ECM. In this study, we utilized both quantitative and global proteomics, alongside single harmonic generation (SHG) and two-photon autofluorescence (TPAF) imaging, to assess changes in dermal composition during intrinsic and extrinsic aging. We find that both intrinsic and extrinsic aging result in significant decreases in ECM-supporting proteoglycans and structural ECM integrity, evidenced by decreasing collagen abundance and increasing fibril fragmentation. Intrinsic aging also produces changes distinct from those produced by photoaging, including reductions in elastic fiber and crosslinking enzyme abundance. In contrast, photoaging is primarily defined by increases in elastic fiber-associated protein and pro-inflammatory proteases. Changes associated with photoaging are evident even in young (mid 20s) sun-exposed forearm skin, indicating that proteomic evidence of photoaging is present decades prior to clinical signs of photoaging. GO term enrichment revealed that both intrinsic aging and photoaging share common features of chronic inflammation. The proteomic data has been deposited to the ProteomeXchange Consortium via the PRIDE partner repository with the data set identifier PXD015982.

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Intrinsic aging and photoaging both decrease ECM-supporting proteoglycans and structural ECM.

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Intrinsic aging produces reductions in elastic fiber and crosslinking enzyme abundance.

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Photoaging results in increases in pro-inflammatory proteases and elastic fiber abundance.

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Intrinsic aging and photoaging share common features associated with chronic inflammation.

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Proteomic changes associated with photoaging are evident decades prior to clinical aging signs.

Esculetin Prevents the Induction of Matrix Metalloproteinase-1 by Hydrogen Peroxide in Skin Keratinocytes

Background

Reactive oxygen species (ROS) are involved in various cellular diseases. Excessive ROS can cause intracellular oxidative stress, resulting in a calcium imbalance and even aging. In this study, we evaluated the protective effect of esculetin on oxidative stress-induced aging in human HaCaT keratinocytes.

Methods

Human keratinocytes were pretreated with esculetin for 30 minutes and treated with H₂O₂. Then, the protective effects on oxidative stress-induced matrix metalloproteinase (MMP)-1 were detected by Flou-4-AM staining, reverse transcription-PCR, Western blotting, and quantitative fluorescence assay.

Results

Esculetin prevented H₂O₂-induced aging by inhibiting MMP-1 mRNA, protein, and activity levels. In addition, esculetin decreased abnormal levels of phospho-MEK1, phospho-ERK1/2, phospho-SEK1, phospho-JNK1/2, c-Fos, and phospho-c-Jun and inhibited activator protein 1 binding activity.

Conclusions

Esculetin prevented excessive levels of intracellular calcium and reduced the expression levels of aging-related proteins.

Scarless wound healing: From development to senescence

An essential element of tissue homeostasis is the response to injuries, cutaneous wound healing being the most studied example. In the adults, wound healing aims at quickly restoring the barrier function of the skin, leading however to scar, a dysfunctional fibrotic tissue. On the other hand, in fetuses a scarless tissue regeneration takes place. During ageing, the wound healing capacity declines; however, in the absence of comorbidities a higher quality in tissue repair is observed. Senescent cells have been found to accumulate in chronic unhealed wounds, but more recent reports indicate that their transient presence may be beneficial for tissue repair. In this review data on skin wound healing and scarring are presented, covering the whole spectrum from early embryonic development to adulthood, and furthermore until ageing of the organism.

Connective Tissue and Age-Related Diseases

We begin this chapter by describing normal characteristics of several pertinent connective tissue components, and some of the basic changes they undergo with ageing. These alterations are not necessarily tied to any specific disease or disorders, but rather an essential part of the normal ageing process. The general features of age-induced changes, such as skin wrinkles, in selected organs with high content of connective or soft tissues are discussed in the next part of the chapter. This is followed by a section dealing with age-related changes in specific diseases that fall into at least two categories. The first category encompasses common diseases with high prevalence among mostly ageing populations where both genetic and environmental factors play roles. They include but may not be limited to atherosclerosis and coronary heart disease, type II diabetes, osteopenia and osteoporosis, osteoarthritis, tendon dysfunction and injury, age-related disorders of spine and joints. Disorders where genetics plays the primary role in pathogenesis and progression include certain types of progeria, such as Werner syndrome and Hutchinson-Gilford progeria belong to the second category discussed in this chapter. These disorders are characterized by accelerated signs and symptoms of ageing. Other hereditary diseases or syndromes that arise from mutations of genes encoding for components of connective tissue and are less common than diseases included in the first group will be discussed briefly as well, though they may not be directly associated with ageing, but their connective tissue undergoes some changes compatible with ageing. Marfan and Ehlers-Danlos syndromes are primary examples of such disorders. We will probe the role of specific components of connective tissue and extracellular matrix if not in each of the diseases, then at least in the main representatives of these disorders.

Matrix Metalloproteinases and Tissue Inhibitor of Metalloproteinases in Inflammation and Fibrosis of Skeletal Muscles

In skeletal muscles, levels and activity of Matrix MetalloProteinases (MMPs) and Tissue Inhibitors of MetalloProteinases (TIMPs) have been involved in myoblast migration, fusion and various physiological and pathological remodeling situations including neuromuscular diseases. This has opened perspectives for the use of MMPs' overexpression to improve the efficiency of cell therapy in muscular dystrophies and resolve fibrosis. Alternatively, inhibition of individual MMPs in animal models of muscular dystrophies has provided evidence of beneficial, dual or adverse effects on muscle morphology or function. We review here the role played by MMPs/TIMPs in skeletal muscle inflammation and fibrosis, two major hurdles that limit the success of cell and gene therapy. We report and analyze the consequences of genetic or pharmacological modulation of MMP levels on the inflammation of skeletal muscles and their repair in light of experimental findings. We further discuss how the interplay between MMPs/TIMPs levels, cytokines/chemokines, growth factors and permanent low-grade inflammation favor cellular and molecular modifications resulting in fibrosis.

Human tissue inhibitor of metalloproteinases-1 improved wound healing in diabetes through its anti-apoptotic effect

Impaired wound healing accompanies severe cell apoptosis in diabetic patients. Tissue inhibitor of metalloproteinases-1 (TIMP-1) was known to have effects on promoting growth and anti-apoptosis for cells. We aimed to determine the actual levels of TIMP-1 and cell apoptosis in: (i) the biopsies of diabetic and non-diabetic foot tissue and (ii) the human fibroblasts with or without treatments of advanced glycation end-products (AGEs). Next, we aimed to determine the improved levels of cell apoptosis and wound healing after the treatments of either active protein of TIMP-1 or in vivo expression of gene therapy vector-mediated TIMP-1 in both the human fibroblasts and the animal model of diabetic rats. The levels of TIMP-1 were significantly reduced in diabetic skin tissues and in AGEs-treated fibroblasts. Both AGEs-treated cells were effectively protected from apoptosis by active protein of TIMP-1 at appropriate dose level. So did the induced in vivo TIMP-1 expression after gene delivery. Similar effects were also found on the significant improvement of impaired wound healing in diabetic rats. We concluded that TIMP-1 improved wound healing through its anti-apoptotic effect. Treatments with either active protein TIMP-1 or TIMP-1 gene therapy delivered in local wound sites may be used as a strategy for accelerating diabetic wound healing.

Resveratrol, 4' Acetoxy Resveratrol, R-equol, Racemic Equol or S-equol as Cosmeceuticals to Improve Dermal Health

Phytochemicals are botanical compounds used in dermatology applications as cosmeceuticals to improve skin health. Resveratrol and equol are two of the best-known polyphenolic or phytoestrogens having similar chemical structures and some overlapping biological functions to 17β-estradiol. Human skin gene expression was reviewed for 28 different biomarkers when resveratrol, 4′ acetoxy resveratrol (4AR), R-equol, racemic equol or S-equol were tested. Sirtuin 1 activator (SIRT 1) was stimulated by resveratrol and 4AR only. Resveratrol, R-equol and racemic equol were effective on the aging biomarkers proliferating cell nuclear factor (PCNA), nerve growth factor (NGF), 5α-reductase and the calcium binding proteins S100 A8 and A9. Racemic equol and 4AR displayed among the highest levels for the collagens, elastin and tissue inhibitor of the matrix metalloproteinase 1 (TIMP 1). S-equol displayed the lowest level of effectiveness compared to the other compounds. The 4AR analog was more effective compared to resveratrol by 1.6-fold. R-equol and racemic equol were almost equal in potency displaying greater inhibition vs. resveratrol or its 4′ analog for the matrix metalloproteinases (MMPs), but among the inflammatory biomarkers, resveratrol, 4AR, R-equol and racemic equol displayed high inhibition. Thus, these cosmeceuticals display promise to improve dermal health; however, further study is warranted to understand how phytochemicals protect/enhance the skin.

The efficacy of human placenta-derived mesenchymal stem cells on radiation enteropathy along with proteomic biomarkers predicting a favorable response

BACKGROUND

Radiation enteropathy is a common complication in patients with abdominopelvic cancer, but no treatment has yet been established. Stem cell therapy may be a viable therapeutic option because intestinal stem cells are highly vulnerable to ionizing radiation (IR) and stem cell loss explains its intractability to general treatment. Here, we investigated either prophylactic or therapeutic efficacy of human placenta-derived mesenchymal stem cells (hPDSCs) against radiation enteropathy and could identify biomarkers predicting a favorable response to stem cell therapy.

METHODS

We challenged a radiation-induced enteropathy model with hPDSCs. After sacrifice, we checked the gross anatomy of small intestine, histology gross, and analyzed that, accompanied with molecular changes implicated in this model.

RESULTS

hPDSCs significantly improved the outcome of mice induced with either radiation enteropathy or lethal radiation syndrome (P < 0.01). hPDSCs exerted inhibitory actions on inflammatory cytokines, the re-establishment of epithelium homeostasis was completed with increasing endogenous restorative processes as assessed with increased levels of proliferative markers in the hPDSCs group, and a significant inhibition of IR-induced apoptosis. The preservation of cells expressing lysozyme, and Musashi-1 were significantly increased in the hPDSC treatment group. Both preventive and therapeutic efficacies of hPDSCs were noted against IR-induced enteropathy. Label-free quantification was used to identify biomarkers which predict favorable responses after hPDSC treatment, and finally glutathione S-transferase-mu type, interleukin-10, and peroxiredoxin-2 were validated as proteomic biomarkers predicting a favorable response to hPDSCs in radiation enteropathy.

CONCLUSIONS

hPDSCs may be a useful prophylactic and therapeutic cell therapy for radiation enteropathy.

Skin aging and oxidative stress: Equol's anti-aging effects via biochemical and molecular mechanisms

Oxygen in biology is essential for life. It comes at a cost during normal cellular function, where reactive oxygen species (ROS) are generated by oxidative metabolism. Human skin exposed to solar ultra-violet radiation (UVR) dramatically increases ROS production/oxidative stress. It is important to understand the characteristics of human skin and how chronological (intrinsic) aging and photo-aging (extrinsic aging) occur via the impact of ROS production by cascade signaling pathways. The goal is to oppose or neutralize ROS insults to maintain good dermal health. Botanicals, as active ingredients, represent one of the largest categories used in dermatology and cosmeceuticals to combat skin aging. An emerging botanical is equol, a polyphenolic/isoflavonoid molecule found in plants and food products and via gastrointestinal metabolism from precursor compounds. Introductory sections cover oxygen, free radicals (ROS), oxidative stress, antioxidants, human skin aging, cellular/molecular ROS events in skin, steroid enzymes/receptors/hormonal actions and genetic factors in aging skin. The main focus of this review covers the characteristics of equol (phytoestrogenic, antioxidant and enhancement of extracellular matrix properties) to reduce skin aging along with its anti-aging skin influences via reducing oxidative stress cascade events by a variety of biochemical/molecular actions and mechanisms to enhance human dermal health.

Serum from calorie-restricted animals delays senescence and extends the lifespan of normal human fibroblasts in vitro

The cumulative effects of cellular senescence and cell loss over time in various tissues and organs are considered major contributing factors to the ageing process. In various organisms, caloric restriction (CR) slows ageing and increases lifespan, at least in part, by activating nicotinamide adenine dinucleotide (NAD⁺)-dependent protein deacetylases of the sirtuin family. Here, we use an in vitro model of CR to study the effects of this dietary regime on replicative senescence, cellular lifespan and modulation of the SIRT1 signaling pathway in normal human diploid fibroblasts. We found that serum from calorie-restricted animals was able to delay senescence and significantly increase replicative lifespan in these cells, when compared to serum from ad libitum fed animals. These effects correlated with CR-mediated increases in SIRT1 and decreases in p53 expression levels. In addition, we show that manipulation of SIRT1 levels by either over-expression or siRNA-mediated knockdown resulted in delayed and accelerated cellular senescence, respectively. Our results demonstrate that CR can delay senescence and increase replicative lifespan of normal human diploid fibroblasts in vitro and suggest that SIRT1 plays an important role in these processes. (185 words).

Antiphotoaging effect of conditioned medium of dedifferentiated adipocytes on skin in vivo and in vitro: a mechanistic study

Photoaging of skin occurs partially due to decreased synthesis and increased degradation of dermal collagen. Antiphotoaging therapy aims to counteract these effects. This study aimed to investigate whether secretory factors from dedifferentiated adipocytes (DAs) could alleviate photoaging in human dermal fibroblasts (HDFs) and in mice and to clarify the underlying mechanism. DAs were acquired and verified based on cellular biomarkers and multilineage differentiation potential. The concentrations of several cytokines in conditioned medium from DAs (DA-CM) were determined. In vivo pathological changes, collagen types I and III, and matrix metalloproteinase (MMP)-1 and -3 were evaluated following the injection of 10-fold concentrated DA-CM into photoaged mice. In vitro, the effect of DA-CM on stress-induced premature senescence in HDFs was investigated by 5-ethynyl-2'-deoxyuridine (EdU) staining and β-galactosidase staining. The influence of DA-CM and transforming growth factor-β1 (TGF-β1) on the secretion of collagen types I and III, MMP-1, and MMP-3 in HDFs was evaluated by ELISA. In vivo, we found that subcutaneously injected 10-fold concentrated DA-CM increased the expression of collagen types I and III. In vitro, DA-CM clearly mitigated the decreased cell proliferation and delayed the senescence status in HDFs induced by ultraviolet B (UVB). HDFs treated with DA-CM exhibited higher collagen types I and III secretion and significantly lower MMP-1 and MMP-3 secretion. The TGF-β1-neutralizing antibody could partially reduce the recovery effect. Our results suggest that DAs may be useful for aging skin and their effects are mainly due to secreted factors, especially TGF-β1, which stimulate collagen synthesis and alleviate collagen degradation in HDFs.

Anti-glycative effects of asiatic acid in human keratinocyte cells

Background: Human skin keratinocyte (HaCaT) cells served to examine effects of asiatic acid (AA) at 1, 2, 4 and 8 μM against advanced glycative endproduct (AGE)-modified bovine serum albumin (BSA) induced glycative stress. Results: AGE-BSA treatment reduced cell viability; and increased reactive oxygen species, nitric oxide, protein carbonyl, interleukin (IL)-1beta and tumor necrosis factor-alpha levels in HaCaT cells. Yet AA pretreatments decreased these oxidative and inflammatory factors, dose-dependently lowering nitric oxide synthase activity and expression. AGE-BSA raised activity and expression of caspase-3 and caspase-8. AA pretreatments at 2-8 μM decreased activity and expression of these two caspases. AGE-BSA declined collagen I expression, but enhanced matrix metalloproteinase (MMP)-1, MMP-8 and MMP-9 protein expression. AA pretreatments at 2-8 μM maintained collagen I expression, and reduced three MMPs expression. AGE-BSA also up-regulated RAGE (receptor of AGE), p-p38 and p-JNK expression. AA pretreatments at 2-8 μM suppressed RAGE expression, and at 1-8 μM down-regulated p-p38 and p-JNK expression. Conclusion: Asiatic acid, via its anti-glycative activity, could protect skin. Thus, this compound could be developed as an external agent and applied for personalized medicine.

Skin Hydration and Collagen Synthesis of AF-343 in HS68 Cell Line and NC/Nga Mice by Filaggrin Expression and Suppression of Matrix Metallopreteinase

Extract of Taraxacum platycarpum (AF-343) has been reported to have several biological properties such as skin hydration and anti-inflammatory effects. Although clinical evidences of skin hydration and antiinflammatory effect were proven in clinical trial, precise mechanism of skin hydration was not fully understood yet. In this study, we have focused skin hydration mechanism related filaggrin, collagen, and matrix metalloproteinase (MMP) in vitro and animal study. Herein, skin hydration mechanism of AF-343 is due to recovery of filaggrin in mice model and increased production of collagen with suppression of matrix MMP in vitro fibroblast cell line.

Hepatic apoptosis can modulate liver fibrosis through TIMP1 pathway

Apoptotic injury participates in hepatic fibrosis, but the molecular mechanisms are not well understood. The present study aimed to investigate the role of inducible TIMP1 in the pathogenesis of hepatic apoptosis-fibrosis. Apoptosis was induced with GCDC, LPS, and alcohol in precision-cut liver slices or bile duct ligation (BDL) in rats, as reflected by caspase-3 activity, TUNEL assay, and apoptosis-related gene profiles. The hepatic fibrosis was detected with Picrosirius staining, hydroxyproline determination, and expression profiling of fibrosis-related genes. Levels of TIMP1 were upregulated by the hepatic apoptosis, but downregulated by caspase inhibitor. The inducible TIMP1 was apoptosis-dependent. Once TIMP1 was inhibited with treatment of TIMP1-siRNA, the fibrotic response was reduced as demonstrated by hydroxyproline assay. In addition, the expression of fibrosis-related genes aSMA, CTGF, and TGFb2r were down-regulated subsequent to the treatment of TIMP1-siRNA. TIMP1 could mediate the expression of fibrosis-related genes. TIMP1 was transcriptionally regulated by nuclear factor c-Jun as demonstrated by EMSA and ChIP assay. The treatment of c-Jun siRNA could significantly decrease the expression of TIMP1 induced by alcohol, GCDC, or LPS treatment. Hepatic apoptosis induces the expression of TIMP1. Inducible TIMP1 can modulate the expression of fibrosis-related genes in liver. TIMP1 pathway is a potential target for therapeutic intervention of fibrotic liver diseases.

Transcriptional events during the recovery from MRSA lung infection: a mouse pneumonia model

Community associated methicillin-resistant Staphylococcus aureus (CA-MRSA) is an emerging threat to human health throughout the world. Rodent MRSA pneumonia models mainly focus on the early innate immune responses to MRSA lung infection. However, the molecular pattern and mechanisms of recovery from MRSA lung infection are largely unknown. In this study, a sublethal mouse MRSA pneumonia model was employed to investigate late events during the recovery from MRSA lung infection. We compared lung bacterial clearance, bronchoalveolar lavage fluid (BALF) characterization, lung histology, lung cell proliferation, lung vascular permeability and lung gene expression profiling between days 1 and 3 post MRSA lung infection. Compared to day 1 post infection, bacterial colony counts, BALF total cell number and BALF protein concentration significantly decreased at day 3 post infection. Lung cDNA microarray analysis identified 47 significantly up-regulated and 35 down-regulated genes (p<0.01, 1.5 fold change [up and down]). The pattern of gene expression suggests that lung recovery is characterized by enhanced cell division, vascularization, wound healing and adjustment of host adaptive immune responses. Proliferation assay by PCNA staining further confirmed that at day 3 lungs have significantly higher cell proliferation than at day 1. Furthermore, at day 3 lungs displayed significantly lower levels of vascular permeability to albumin, compared to day 1. Collectively, this data helps us elucidate the molecular mechanisms of the recovery after MRSA lung infection.

Processed Panax ginseng, Sun Ginseng Increases Type I Collagen by Regulating MMP-1 and TIMP-1 Expression in Human Dermal Fibroblasts

In the present study, effects of sun ginseng (SG) on the collagen synthesis and the proliferation of dermal fibroblast were investigated. Collagen synthesis was measured by assaying procollagen type I C-peptide production. In addition, the level of matrix metalloproteinase (MMP)-1 was assessed by western blot analysis. SG suppressed the MMP-1 protein level in a dose-dependent manner. In contrast, SG dose-dependently increased tissue inhibitors of MMP (TIMP)-1 production in fibroblasts. SG increased type I collagen production directly and/or indirectly by reducing MMP-1 and stimulating TIMP-1 production in human dermal fibroblasts. SG dose-dependently induced fibroblast proliferation and this, in turn, can trigger more collagen production. These results suggest that SG may be a potential pharmacological agent with anti-aging properties in cultured human skin fibroblast.

Transcriptome characterization by RNA-Seq reveals the involvement of the complement components in noise-traumatized rat cochleae

Acoustic trauma, a leading cause of sensorineural hearing loss in adults, induces a complex degenerative process in the cochlea. Although previous investigations have identified multiple stress pathways, a comprehensive analysis of cochlear responses to acoustic injury is still lacking. In the current study, we used the next-generation RNA-sequencing (RNA-Seq) technique to sequence the whole transcriptome of the normal and noise-traumatized cochlear sensory epithelia (CSE). CSE tissues were collected from rat inner ears 1d after the rats were exposed to a 120-dB (sound pressure level) noise for 2 h. The RNA-Seq generated over 176 million sequence reads for the normal CSE and over 164 million reads for the noise-traumatized CSE. Alignment of these sequences with the rat Rn4 genome revealed the expression of over 17,000 gene transcripts in the CSE, over 2000 of which were exclusively expressed in either the normal or noise-traumatized CSE. Seventy-eight gene transcripts were differentially expressed (70 upregulated and 8 downregulated) after acoustic trauma. Many of the differentially expressed genes are related to the innate immune system. Further expression analyses using quantitative real time PCR confirmed the constitutive expression of multiple complement genes in the normal organ of Corti and the changes in the expression levels of the complement factor I (Cfi) and complement component 1, s subcomponent (C1s) after acoustic trauma. Moreover, protein expression analysis revealed strong expression of Cfi and C1s proteins in the organ of Corti. Importantly, these proteins exhibited expression changes following acoustic trauma. Collectively, the results of the current investigation suggest the involvement of the complement components in cochlear responses to acoustic trauma.

Extracellular regulated kinase 1/2 signaling is a critical regulator of interleukin-1β-mediated astrocyte tissue inhibitor of metalloproteinase-1 expression

Astrocytes are essential for proper central nervous system (CNS) function and are intricately involved in neuroinflammation. Despite evidence that immune-activated astrocytes contribute to many CNS pathologies, little is known about the inflammatory pathways controlling gene expression. Our laboratory identified altered levels of tissue inhibitor of metalloproteinase (TIMP)-1 in brain lysates from human immunodeficiency virus (HIV)-1 infected patients, compared to age-matched controls, and interleukin (IL)-1β as a key regulator of astrocyte TIMP-1. Additionally, CCAAT enhancer binding protein (C/EBP)β levels are elevated in brain specimens from HIV-1 patients and the transcription factor contributes to astrocyte TIMP-1 expression. In this report we sought to identify key signaling pathways necessary for IL-1β-mediated astrocyte TIMP-1 expression and their interaction with C/EBPβ. Primary human astrocytes were cultured and treated with mitogen activated protein kinase-selective small molecule inhibitors, and IL-1β. TIMP-1 and C/EBPβ mRNA and protein expression were evaluated at 12 and 24 h post-treatment, respectively. TIMP-1 promoter-driven luciferase plasmids were used to evaluate TIMP-1 promoter activity in inhibitor-treated astrocytes. These data show that extracellular regulated kinase (ERK) 1/2-selective inhibitors block IL-1β-induced astrocyte TIMP-1 expression, but did not decrease C/EBPβ expression in parallel. The p38 kinase (p38K) inhibitors partially blocked both IL-1β-induced astrocyte TIMP-1 expression and C/EBPβ expression. The ERK1/2-selective inhibitor abrogated IL-1β-mediated increases in TIMP-1 promoter activity. Our data demonstrate that ERK1/2 activation is critical for IL-1β-mediated astrocyte TIMP-1 expression. ERK1/2-selective inhibition may elicit a compensatory response in the form of enhanced IL-1β-mediated astrocyte C/EBPβ expression, or, alternatively, ERK1/2 signaling may function to moderate IL-1β-mediated astrocyte C/EBPβ expression. Furthermore, p38K activation contributes to IL-1β-induced astrocyte TIMP-1 and C/EBPβ expression. These data suggest that ERK1/2 signals downstream of C/EBPβ to facilitate IL-1β-induced astrocyte TIMP-1 expression. Astrocyte ERK1/2 and p38K signaling may serve as therapeutic targets for manipulating CNS TIMP-1 and C/EBPβ levels, respectively.

Pluripotent stem cell-engineered cell sheets reassembled with defined cardiovascular populations ameliorate reduction in infarct heart function through cardiomyocyte-mediated neovascularization

Although stem cell therapy is a promising strategy for cardiac restoration, the heterogeneity of transplanted cells has been hampering the precise understanding of the cellular and molecular mechanisms. Previously, we established a cardiovascular cell differentiation system from mouse pluripotent stem cells, in which cardiomyocytes (CMs), endothelial cells (ECs), and mural cells (MCs) can be systematically induced and purified. Combining this with cell sheet technology, we generated cardiac tissue sheets reassembled with defined cardiovascular populations. Here, we show the potentials and mechanisms of cardiac tissue sheet transplantation in cardiac function after myocardial infarction (MI). Transplantation of the cardiac tissue sheet to a rat MI model showed significant and sustained improvement of systolic function accompanied by neovascularization. Reduction of the infarct wall thinning and fibrotic length indicated the attenuation of left ventricular remodeling. Cell tracing with species-specific fluorescent in situ hybridization after transplantation revealed a relatively early loss of transplanted cells and an increase in endogenous neovascularization in the proximity of the graft, suggesting an indirect angiogenic effect of cardiac tissue sheets rather than direct CM contributions. We prospectively dissected the functional mechanisms with cell type-controlled sheet analyses. Sheet CMs were the main source of vascular endothelial growth factor. Transplantation of sheets lacking CMs resulted in the disappearance of neovascularization and subsequent functional improvement, indicating that the beneficial effects of the sheet were achieved by sheet CMs. ECs and MCs enhanced the sheet functions and structural integration. Supplying CMs to ischemic regions with cellular interaction could be a strategic key in future cardiac cell therapy.

Impact of intense pulsed light irradiation on cultured primary fibroblasts and a vascular endothelial cell line

The aim of this study was to determine the effects of intense pulsed light (IPL) on cell proliferation and the secretion of vascular endothelial growth factor (VEGF) and matrix metalloproteinases (MMPs) in human fibroblasts and vascular endothelial cell lines, and to investigate the effects of IPL on the mRNA expression levels of type I and III procollagens in cultured human fibroblasts. Foreskin fibroblasts and a vascular endothelial cell line (ECV034) were cultured and treated with various wavelengths and doses of IPL irradiation. After culture for 1, 12, 24 and 48 h following IPL irradiation, fibroblasts and the vascular endothelial cell line were harvested for investigation of morphological changes by light microscopy, cell proliferation viability by MTT assay, and VEGF and MMP secretions by ELISA. The mRNA expression levels of type I and III procollagens in the fibroblasts were detected by RT-PCR. No marked morphological changes were observed in the cultured fibroblasts compared with the control. Cell growth and cellular viability were increased in fibroblasts 24 and 48 h after IPL irradiation. The levels of type I and III procollagen mRNA expression in fibroblasts increased in a time-dependent manner. However, the IPL management had no impact on VEGF and MMP secretion levels in fibroblasts and the ECV034 cell line at any time-point after irradiation as well as cell morphology and cellular proliferation. IPL irradiation may induce cellular proliferation and promote the expression of procollagen mRNAs directly in cultured primary fibroblasts, which may primarily contribute to photorejuvenation.

Effects of Herbal Medicinal Formulas on Suppressing Viral Replication and Modulating Immune Responses

The Chinese medicinal herbs Radix Isatidis and Viola yedoensis Makino have been suggested to possess antiviral activity. This study tests whether these and other Chinese and Western herbal medicinal formulas can modulate the immune functions involving virus-suppression in BALB/c mouse. We first confirmed the extract from Viola yedoensis Makino, but not from Radix Isatidis, the traditional Chinese medicine (TCM) formula Chui-Uren-Chien (CUC), or a Western homeopathic medicinal drink Método Canova, could inhibit the replications of herpes simplex virus-1 and enterovirus 71 in the human neuroblastoma SK-N-SH cell line. Subsequently, the same herbal extracts and drink underwent toxicity and immunomodulatory tests on mice of 5–7 weeks old. After 8 weeks of feeding different herbal medicinal formulas, no hepatic or renal toxicity was noted in any tested animal; whereas among the immune function evaluations, only the mice treated with CUC extract were found to be associated with significant increases (p < 0.05) in both the level of plasma IgG and the percentage of monocyte in blood mononuclear cells as well as the activation of macrophage Raw264.7 cells for nitric oxide production, suggesting its role in modulating the non-specific immune response. Analyses using protein arrays showed CUC was the most potent herbal medicinal formula eliciting fluctuations in plasma cytokine and chemokine concentrations. Taking all experimental data together, we conclude Chui-Uren-Chien possesses immunomodulatory capability in mouse, but none of the herbal medicinal formulas tested here are involved in strengthening antiviral immunity.

Notochordal cells protect nucleus pulposus cells from degradation and apoptosis: implications for the mechanisms of intervertebral disc degeneration

Introduction

The relative resistance of non-chondrodystrophic (NCD) canines to degenerative disc disease (DDD) may be due to a combination of anabolic and anti-catabolic factors secreted by notochordal cells within the intervertebral disc (IVD) nucleus pulposus (NP). Factors known to induce DDD include interleukin-1 beta (IL-1ß) and/or Fas-Ligand (Fas-L). Therefore we evaluated the ability of notochordal cell conditioned medium (NCCM) to protect NP cells from IL-1ß and IL-1ß +FasL-mediated cell death and degeneration.

Methods

We cultured bovine NP cells with IL-1ß or IL-1ß+FasL under hypoxic serum-free conditions (3.5% O₂) and treated the cells with either serum-free NCCM or basal medium (Advanced DMEM/F-12). We used flow cytometry to evaluate cell death and real-time (RT-)PCR to determine the gene expression of aggrecan, collagen 2, and link protein, mediators of matrix degradation ADAMTS-4 and MMP3, the matrix protection molecule TIMP1, the cluster of differentiation (CD)44 receptor, the inflammatory cytokine IL-6 and Ank. We then determined the expression of specific apoptotic pathways in bovine NP cells by characterizing the expression of activated caspases-3, -8 and -9 in the presence of IL-1ß+FasL when cultured with NCCM, conditioned medium obtained using bovine NP cells (BCCM), and basal medium all supplemented with 2% FBS.

Results

NCCM inhibits bovine NP cell death and apoptosis via suppression of activated caspase-9 and caspase-3/7. Furthermore, NCCM protects NP cells from the degradative effects of IL-1ß and IL-1ß+Fas-L by up-regulating the expression of anabolic/matrix protective genes (aggrecan, collagen type 2, CD44, link protein and TIMP-1) and down-regulating matrix degrading genes such as MMP-3. Expression of ADAMTS-4, which encodes a protein for aggrecan remodeling, is increased. NCCM also protects against IL-1+FasL-mediated down-regulation of Ank expression. Furthermore, NP cells treated with NCCM in the presence of IL-1ß+Fas-L down-regulate the expression of IL-6 by almost 50%. BCCM does not mediate cell death/apoptosis in target bovine NP cells.

Conclusions

Notochordal cell-secreted factors suppress NP cell death by inhibition of activated caspase-9 and -3/7 activity and by up-regulating genes contributing anabolic activity and matrix protection of the IVD NP. Harnessing the restorative powers of the notochordal cell could lead to novel cellular and molecular strategies in the treatment of DDD.

CCAAT/enhancer binding protein β expression is increased in the brain during HIV-1-infection and contributes to regulation of astrocyte tissue inhibitor of metalloproteinase-1

Human immunodeficiency virus (HIV)-1-associated neurocognitive disorders (HAND) associated with infection and activation of mononuclear phagocytes (MP) in the brain, occur late in disease. Infected/activated MP initiate neuroinflammation activating glial cells and ultimately disrupting neuronal function. Astrocytes secrete tissue inhibitor of metalloproteinase (TIMP)-1 in response to neural injury. Altered TIMP-1 levels are implicated in several CNS diseases. CCAAT enhancer-binding protein β (C/EBPβ), a transcription factor, is expressed in rodent brains in response to neuroinflammation, implicating it in Alzheimer's, Parkinson's, and HAND. Here, we report that C/EBPβ mRNA levels are elevated and its isoforms differentially expressed in total brain tissue lysates of HIV-1-infected and HIV-1 encephalitis patients. In vitro, HAND-relevant stimuli additively induce C/EBPβ nuclear expression in human astrocytes through 7 days of treatment. Over-expression of C/EBPβ increases TIMP-1 promoter activity, mRNA, and protein levels in human astrocytes activated with interleukin-1β. Knockdown of C/EBPβ with siRNA decreases TIMP-1 mRNA and protein levels. These data suggest that C/EBPβ isoforms are involved in complex regulation of astrocyte TIMP-1 production during HIV-1 infection; however, further studies are required to completely understand their role during disease progression.

Redox-control of matrix metalloproteinase-1: a critical link between free radicals, matrix remodeling and degenerative disease

Many degenerative disease processes associated with aging result from enhanced extracellular matrix (ECM) breakdown. Concomitant with aberrant matrix destruction are alterations in levels of reactive oxygen species (ROS) generating and detoxification systems. ROS function as second messengers due to their ability to react with wide range of biomolecules resulting in modification of an array of signaling networks. ROS can activate upstream kinases (MKK) responsible for MAPK activation and restrict the activity of their inhibitory phosphatases. Here we focus on the redox-sensitive signaling components that control the expression of MMP-1, which is largely responsible for maintaining ECM homeostasis. Numerous disease processes are associated with shifts in steady state ROS levels that influence overall ECM degradation. This review highlights the redox-sensitive regulatory signals that control the expression of the primary initiating protease MMP-1 and provides strong rational for the use of antioxidant based therapies for treatment of degenerative disorders associated with aberrant matrix destruction.

Collagen extracts derived from young and aged mice demonstrate different structural properties and cellular effects in three-dimensional gels

Three-dimensional (3D) type I collagen gels are increasingly utilized to simulate extracellular matrix (ECM) in vivo, but little is known about the effects of age on this model. Collagen was extracted from young (4-6 months) and aged (20-24 months) mice tails and compared. The collagens appeared similar by electrophoresis. However, relative to young, aged collagen formed fibrils slower and generated 3D gels with smaller diameter, less dense fibrils (75 vs 34 nm diameter and 8 vs 3.5% area, for young and aged respectively, p < 0.02). Correspondingly, aged collagen gels were more malleable and contractible (5% vs 19% compression, p < .02, and 73% vs 15.5% area, p < .01, for young and aged, respectively). Fibroblasts cultured within young and aged collagen gels had differential expression of a limited number of genes and proteins corresponding to specific integrins and matrix components. In summary, collagen extracted from young and aged mice is an effective means to examine the influence of aging on functional properties of ECM that are relevant in vivo.

Effect of chloroquine phosphate treatment on serum MMP-9 and TIMP-1 levels in patients with systemic lupus erythematosus

Antimalarials are widely used for the treatment of systemic lupus erythematosus. However, their mechanisms of action have not been fully elucidated. Literature data indicate that matrix metalloproteinases may play a role in the immune response and tissue damage that occur in autoimmune skin diseases. The aim of this study was to determine the effect of 3 months of chloroquine treatment on serum levels of MMP-9 and TIMP-1 in patients with systemic lupus erythematosus. The study group consisted of 25 patients with systemic lupus erythematosus and 25 sex- and age-matched healthy volunteers. Before drug administration, serum levels of MMP-9 and TIMP-1 were determined by enzyme-linked immunosorbent assay. The same procedure was performed after chloroquine treatment. We found significantly higher median serum levels of MMP-9 in patients with systemic lupus erythematosus before therapy (57.20 ng/ml) when compared with controls (44.50 ng/ml) (p < 0.001). After chloroquine therapy the median MMP-9 serum level of systemic lupus erythematosus patients decreased significantly (43 ng/ml; p < 0.001). Before treatment the median TIMP-1 serum level in the patients with systemic lupus erythematosus was significantly higher than in the control group (500 vs. 200 ng/ml; p < 0.001), and after therapy it increased significantly (750 ng/ml TIMP-1; p < 0.001). The results suggest that chloroquine treatment may affect the matrix metalloproteinase network, and this effect may contribute to the immunoregulatory and anti-inflammatory properties of antimalarials.

Regulation of cytokine signaling and T-cell recruitment in the aging mouse brain in response to central inflammatory challenge

Aging is often accompanied by increased levels of inflammatory molecules in the organism, but age-related changes in the brain response to inflammatory challenges still require clarification. We here investigated in mice whether cytokine signaling and T-cell neuroinvasion undergo age-related changes. We first analyzed the expression of molecules involved in T-cell infiltration and cytokine signaling regulation in the septum and hippocampus of 2-3 months and 20- to 24-month-old mice at 4h after intracerebroventricular injections of tumor necrosis factor (TNF)-alpha or interferon-gammaversus saline injections. Transcripts of the chemokine CXCL9, intercellular adhesion molecule (ICAM)-1 and suppressor of cytokine signaling molecules (SOCS) 1 and 3 were increased in both age groups after cytokine injection; microglia-derived matrix metalloproteinase (MMP) 12 mRNA was induced in old mice also after control saline injections. Age-related changes in ICAM-1 protein expression and T-cell infiltration were then analyzed in mice of 3-4, 8-9 and 15-16 months at 48h after TNF-alpha injections. ICAM-1 immunoreactivity, and Western blotting in striatum, septum, hippocampus and hypothalamus showed progressive age-related enhancement of TNF-alpha-elicited ICAM-1 upregulation. Double immunofluorescence revealed ICAM-1 expression in microglia and astrocytic processes. CD3(+), CD4(+) and CD8(+) T-cells exhibited progressive age-related increases in brain parenchyma and choroid plexus after cytokine exposure. The findings indicate that the brain responses to inflammatory challenges are not only preserved with advancing age, but also include gradual amplification of ICAM-1 expression and T-cell recruitment. The data highlight molecular and cellular correlates of age-related increase of brain sensitivity to inflammatory stimuli, which could be involved in altered brain vulnerability during aging.

Two new lipoaminoacids with complementary modes of action: new prospects to fight out against skin aging

The mode of action of two cosmetic active ingredients (AIs), palmitoyl glycine (PG) and cocoyl alanine (CA) was studied with cDNA array experiments and quantitative PCR confirmations, which were performed on experimentally aged human fibroblasts. These preliminary studies revealed complementary profiles. Thus, specific supplementary investigations were then carried out for each AI. Protocols used were based either on in vitro models: (i) biochemical assays, (ii) monolayer cell culture (primary human fibroblasts and keratinocytes) and (iii) the model of capillary-like tube formation by human endothelial cells or on ex vivo models, i.e. topically treated skin explants and both immunohistochemical and Chromameter(TM) investigations. New prospects are proposed to fight out against skin aging. Indeed, PG and CA showed complementary properties and thus enabled a regulation or a restoration effect on main aging-associated disorders. Thus, they can not only act on tissue architecture, cell-cell interactions and extracellular matrix protection but also on inflammation, cell longevity, skin immune system protection, skin radiance and stem cell survey. Finally, a clinical trial performed on Caucasian women confirmed AI anti-wrinkle efficacy, which was superior to that of a market reference ingredient. In the future, complementary experiments enabling a better understanding of the aging-induced decline of epidermal stem cells would be of a great interest.

Age-dependent increases in interstitial collagenase and MAP Kinase levels are exacerbated by superoxide dismutase deficiencies

Many age-associated degenerative diseases commonly involve degradation of the extracellular matrix and aberrant matrix metalloproteinase-1 (MMP-1) expression. In diverse cell lines MMP-1 or interstitial collagenase (CL) expression is tightly regulated through a network of signals involving reactive oxygen species (ROS). However, whether the in vivo age-associated increase in CL expression is also sensitive to ROS-mediated signaling has not been established. To evaluate the contribution of ROS to the age-dependent increase in CL we monitored the levels of murine CL in two well-established models of oxidant stress. Analysis of murine CL levels in mice deficient in either of the intracellular superoxide dismutases (Sod2(+/-) or Sod1(-/-)) revealed its age- and redox-dependent expression relative to WT controls. Both age- and redox-dependent increases in murine CL expression were associated with elevations in phosphorylation of the MAP Kinases, Erk, JNK and p38. CL expression was highest in renal and skeletal muscle tissue from the aged Sod1(-/-) mice and was associated with a decrease in collagen staining. These findings suggest that MAPK signaling and CL production are both age- and redox-responsive. The redox sensitivity of age-associated CL expression suggests that degenerative disease associated with aberrant matrix remodeling and oxidant stress may be amenable to antioxidant-based therapies.

Cellular senescence, ageing and disease

Cellular senescence is the irreversible growth arrest of individual mitotic cells, which as a consequence display a radically altered phenotype that is thought to impair tissue function and predispose tissues to disease development and/or progression as they gradually accumulate. However, in the past, research into mechanisms of ageing has commonly been researched and treated separately from disease development. This may partly be due to the lack of understanding concerning mechanisms of ageing and the difficulty in implementing what was known into models of disease development. Only in the last 10 years, with increasing knowledge of the senescent phenotype and the ability to detect senescent cells in human tissues, have biologists been able to investigate the relationship between cellular senescence and disease. This review therefore brings together and discusses recent findings which suggest that cellular senescence does contribute to ageing and the development/progression of disease.