Low cytotoxic quinoline-4-carboxylic acids derived from vanillin precursors as potential human dihydroorotate dehydrogenase inhibitors.

Twenty novel 2-substituted quinoline-4-carboxylic acids bearing amide moiety were designed and synthesized by Doebner reaction. Human dihydroorotate dehydrogenase (hDHODH) was recognized as a biological target and all compounds were screened as potential hDHODH inhibitors in an enzyme inhibition assay. The prepared heterocycles were also evaluated for their cytotoxic effects on the healthy HaCaT cell line while lipophilic properties were considered on the basis of experimentally determined logD values at physiological pH. The most promising compound 5j, with chlorine at para-position of terminal phenyl ring, showed good hDHODH inhibitory activity, low cytotoxicity, and optimal lipophilicity. The bioactive conformation of 5j on the hDHODH, determined by means of molecular docking, revealed the compound's pharmacology and provide guidelines for further lead optimization.

Potent human dihydroorotate dehydrogenase inhibitory activity of new quinoline-4-carboxylic acids derived from phenolic aldehydes: Synthesis, cytotoxicity, lipophilicity and molecular docking studies.

A series of novel 2-substituted quinoline-4-carboxylic acids was synthesized by Doebner reaction starting from freely available protocatechuic aldehyde and vanillin precursors. Human dihydroorotate dehydrogenase (hDHODH) was recognised as a clear molecular target for these heterocycles. All compounds were also tested for their antiproliferative potential against three cancer cells (MCF-7, A549, A375) and one normal cell line (HaCaT) to evaluate the selective cytotoxicity. Quinoline derivatives 3f and 3g were identified as potent hDHODH inhibitors while 3k and 3l demonstrated high cytotoxic activity against MCF-7 and A375 cells and good selectivity. In addition, the logD7.4 values obtained by the experimental method were found to be in the range from -1.15 to 1.69. The chemical structures of all compounds were confirmed by IR, NMR and elemental analysis. The compounds pharmacology on the molecular level was revealed by means of molecular docking, highlighting the structural differences that distinguish highly active from medium and low active hDHODH inhibitors.

In vitro effects of 635 nm photobiomodulation under hypoxia/reoxygenation culture conditions.

Photobiomodulation (PBM), especially in the red wavelength range, has been demonstrated to be an effective treatment option for superficial and chronic wounds. However, ischemia and subsequent reperfusion can further challenge wound healing. Therefore, we investigated the effect of pulsed red LED light at 635 nm on cellular function in an in-vitro model of hypoxia/reoxygenation (H/R) challenge. Mouse myoblasts and fibroblasts were incubated in oxygen-deprived starvation medium (hypoxia) for 3 h after which the media was changed to oxygenated, fully supplemented media to simulate reperfusion. Cells were then treated with pulsed red LED light at a wavelength of 635 nm at 40 mW/cm2. Mitochondrial respiratory activity, ATP production and ROS levels were analysed immediately post-illumination. The effects on cellular metabolic activity and proliferation were measured at 6 h and 24 h and apoptosis/necrosis was measured at 24 h post-illumination. Our results show that both cell types reacted differently to H/R challenge and PBM. PBM of H/R-challenged cells enhanced mitochondrial activity and rescued decreased ATP levels, with significant effects in fibroblasts. This was associated with increased cell proliferation rates in both cell types. The increase was again more pronounced in fibroblasts. Our study concluded that PBM with red LED light significantly restored ATP levels during H/R and effectively promoted cell growth under both normoxic and H/R conditions. In clinical applications, PBM has been repeatedly reported to resolve difficult clinical situations in which ischemia/reperfusion injuries are a major issue. Our study confirms the beneficial effects of PBM especially in H/R-challenged cells.

Mechanical Stimulation of Fibroblasts by Extracorporeal Shock Waves: Modulation of Cell Activation and Proliferation Through a Transient Proinflammatory Milieu.

Extracorporeal shock waves (ESWTs) are "mechanical" waves, widely used in regenerative medicine, including soft tissue wound repair. Although already being used in the clinical practice, the mechanism of action underlying their biological activities is still not fully understood. In the present paper we tried to elucidate whether a proinflammatory effect may contribute to the regenerative potential of shock waves treatment. For this purpose, we exposed human foreskin fibroblasts (HFF1 cells) to an ESWT treatment (100 pulses using energy flux densities of 0.19 mJ/mm2 at 3 Hz), followed by cell analyses after 5 min, up to 48 h. We then evaluated cell proliferation, reactive oxygen species generation, ATP release, and cytokine production. Cells cultured in the presence of lipopolysaccharide (LPS), to induce inflammation, were used as a positive control, indicating that LPS-mediated induction of a proinflammatory pattern in HFF1 increased their proliferation. Here, we provide evidence that ESWTs affected fibroblast proliferation through the overexpression of selected cytokines involved in the establishment of a proinflammatory program, superimposable to what was observed in LPS-treated cells. The possibility that inflammatory circuits can be modulated by ESWT mechanotransduction may disclose novel hypothesis on their biological underpinning and expand the fields of their biomedical application.

The impact of wavelengths of LED light-therapy on endothelial cells.

Low level light therapy receives increasing interest in the fields of tissue regeneration and wound healing. Several in vivo studies demonstrated the positive effects of LLLT on angiogenesis. This study aimed to investigate the underlying properties in vitro by comparing the effects of light therapy by light emitting diodes of different wavelengths on endothelial cells in vitro. Human umbilical vein endothelial cells were treated with either 475 nm, 516 nm or 635 nm light. Control cells were not illuminated. 2D proliferation was quantified by manual counting. HUVEC migration was analyzed by performing a 2D wound scratch assay and a 3D bead assay. The influence of LLLT on early vasculogenic events was determined in a 3D fibrin co-culture model with adipose-derived stem cells. Stimulation with both red and green pulsed LED light significantly increased HUVEC proliferation and 3D migration. Moreover, HUVEC showed increased 2D migration potential with green light stimulation. The treatment with blue light was ineffective. Several parameters showed that green light was even more potent to stimulate proliferation and migration of endothelial cells than clinically well-established red light therapy. Further studies have to focus on intracellular mechanisms induced by different wavelengths in order to optimize this promising therapy in tissue regeneration.

Low level light therapy by LED of different wavelength induces angiogenesis and improves ischemic wound healing.

BACKGROUND AND OBJECTIVE: Low-level light therapy (LLLT) has been revealed as a potential means to improve wound healing. So far, most studies are being performed with irradiation in the red to near-infrared spectra. Recently, we showed that blue light (470 nm) can significantly influence biological systems such as nitric oxide (NO) metabolism and is able to release NO from nitrosyl-hemoglobin or mitochondrial protein complexes. Therefore, the aim of this study was to evaluate and compare the therapeutic value of blue or red light emitting diodes (LEDs) on wound healing in an ischemia disturbed rodent flap model. STUDY DESIGN/MATERIALS AND METHODS: An abdominal flap was rendered ischemic by ligation of one epigastric bundle and subjected to LED illumination with a wavelength of 470 nm (blue, n = 8) or 629 nm (red, n = 8) each at 50 mW/cm(2) and compared to a non-treated control group (n = 8). Illumination was performed for 10 minutes on five consecutive days. RESULTS: LED therapy with both wavelengths significantly increased angiogenesis in the sub-epidermal layer and intramuscularly (panniculus carnosus muscle) which was associated with significantly improved tissue perfusion 7 days after the ischemic insult. Accordingly, tissue necrosis was significantly reduced and shrinkage significantly less pronounced in the LED-treated groups of both wavelengths. CONCLUSIONS: LED treatment of ischemia challenged tissue improved early wound healing by enhancing angiogenesis irrespective of the wavelength thus delineating this noninvasive means as a potential, cost effective tool in complicated wounds.