Concern about the Effectiveness of mRNA Vaccination Technology and Its Long-Term Safety: Potential Interference on miRNA Machinery.

After the outbreak of the pandemic due to COVID-19 infection, several vaccines were developed on short timelines to counteract the public health crisis. To allow the administration of mRNA vaccines through a faster-paced approval process, the Emergency Use Authorization (EUA) was applied. The Ba.5 (omicron) variant of SARS-CoV-2 is the predominant one at this moment. Its highly mutable single-stranded RNA genome, along with its high transmissivity, generated concern about the effectiveness of vaccination. The interaction between the vaccine and the host cell is finely regulated by miRNA machinery, a complex network that oversees a wide range of biological processes. The dysregulation of miRNA machinery has been associated with the development of clinical complications during COVID-19 infection and, moreover, to several human pathologies, among which is cancer disease. Now that in some areas, four doses of mRNA vaccine have been administered, it is natural to wonder about its effectiveness and long-term safety.

The Dual Role of Necroptosis in Pancreatic Ductal Adenocarcinoma.

Pancreatic cancer (PC) is the seventh leading cause of cancer-related death. PC incidence has continued to increase by about 1% each year in both men and women. Although the 5-year relative survival rate of PC has increased from 3% to 12%, it is still the lowest among cancers. Hence, novel therapeutic strategies are urgently needed. Challenges in PC-targeted therapeutic strategies stem from the high PC heterogeneity and from the poorly understood interplay between cancer cells and the surrounding microenvironment. Signaling pathways that drive PC cell growth have been the subject of intense scrutiny and interest has been attracted by necroptosis, a distinct type of programmed cell death. In this review, we provide a historical background on necroptosis and a detailed analysis of the ongoing debate on the role of necroptosis in PC malignant progression.

Hydroxytyrosol Reduces Foam Cell Formation and Endothelial Inflammation Regulating the PPARγ/LXRα/ABCA1 Pathway.

Cholesterol accumulation in macrophages leads to the formation of foam cells and increases the risk of developing atherosclerosis. We have verified whether hydroxytyrosol (HT), a phenolic compound with anti-inflammatory and antioxidant properties, can reduce the cholesterol build up in THP-1 macrophage-derived foam cells. We have also investigated the potential mechanisms. Oil Red O staining and high-performance liquid chromatography (HPLC) assays were utilized to detect cellular lipid accumulation and cholesterol content, respectively, in THP-1 macrophages foam cells treated with HT. The impact of HT on cholesterol metabolism-related molecules (SR-A1, CD36, LOX-1, ABCA1, ABCG1, PPARγ and LRX-α) in foam cells was assessed using real-time PCR (RT-qPCR) and Western blot analyses. Finally, the effect of HT on the adhesion of THP-1 monocytes to human vascular endothelial cells (HUVEC) was analyzed to study endothelial activation. We found that HT activates the PPARγ/LXRα pathway to upregulate ABCA1 expression, reducing cholesterol accumulation in foam cells. Moreover, HT significantly inhibited monocyte adhesion and reduced the levels of adhesion factors (ICAM-1 and VCAM-1) and pro-inflammatory factors (IL-6 and TNF-α) in LPS-induced endothelial cells. Taken together, our findings suggest that HT, with its ability to interfere with the import and export of cholesterol, could represent a new therapeutic strategy for the treatment of atherosclerotic disease.

Effects of Focused Vibrations on Human Satellite Cells.

Skeletal muscle consists of long plurinucleate and contractile structures, able to regenerate and repair tissue damage by their resident stem cells: satellite cells (SCs). Reduced skeletal muscle regeneration and progressive atrophy are typical features of sarcopenia, which has important health care implications for humans. Sarcopenia treatment is usually based on physical exercise and nutritional plans, possibly associated with rehabilitation programs, such as vibratory stimulation. Vibrations stimulate muscles and can increase postural stability, balance, and walking in aged and sarcopenic patients. However, the possible direct effect of vibration on SCs is still unclear. Here, we show the effects of focused vibrations administered at increasing time intervals on SCs, isolated from young and aged subjects and cultured in vitro. After stimulations, we found in both young and aged subjects a reduced percentage of apoptotic cells, increased cell size and percentage of aligned cells, mitotic events, and activated cells. We also found an increased number of cells only in young samples. Our results highlight for the first time the presence of direct effects of mechanical vibrations on human SCs. These effects seem to be age-dependent, consisting of a proliferative response of cells derived from young subjects vs. a differentiative response of cells from aged subjects.

Human amniotic fluid stem cells are able to form embryoid body-like aggregates which performs specific functions: morphological evidences.

Human second trimester Amniotic Fluid Stem Cells (hAFSCs) harbour the potential to differentiate into cells of each of the three germ layers and to form Embryoid Body (EB)-like aggregates, without inducing teratoma formation and with no ethical concerns. However, in spite of the number of reports on hAFSCs-EBs and their characterization, a thorough evaluation in light and electron microscopy of morphological and morphometric features of hAFSCs-EBs development in vitro has not been reported yet. Apart from a superficial layer of epithelial-like flat cells, displaying rare microvilli on the free surface, hAFSCs-EBs enclose inner material, abundant in vesicles and secretory granules, showing early characteristics of connective extracellular matrix dispersed among different types of inner cells. The observation of a number of microvesicles mainly represented by microparticles and, to a lower extent, by exosomes indicates the presence of a complex cellular communication system within this structure. According to morphological analysis, after 7 days of in vitro culture hAFSCs-EB appears as a well-organized corpuscle, sufficiently young to be a carrier of stemness and at the same time, when appropriately stimulated, able to differentiate. In fact, 7-day hAFSCs-EB represents itself an initial cellular transformation towards a specialized structure both in recording and in providing different stimuli from the surrounding environment, organizing structures and cells towards a differentiation fate.

Biological Factors, Metals, and Biomaterials Regulating Osteogenesis through Autophagy.

Bone loss raises great concern in numerous situations, such as ageing and many diseases and in both orthopedic and dentistry fields of application, with an extensive impact on health care. Therefore, it is crucial to understand the mechanisms and the determinants that can regulate osteogenesis and ensure bone balance. Autophagy is a well conserved lysosomal degradation pathway, which is known to be highly active during differentiation and development. This review provides a revision of the literature on all the exogen factors that can modulate osteogenesis through autophagy regulation. Metal ion exposition, mechanical stimuli, and biological factors, including hormones, nutrients, and metabolic conditions, were taken into consideration for their ability to tune osteogenic differentiation through autophagy. In addition, an exhaustive overview of biomaterials, both for orthopedic and dentistry applications, enhancing osteogenesis by modulation of the autophagic process is provided as well. Already investigated conditions regulating bone regeneration via autophagy need to be better understood for finely tailoring innovative therapeutic treatments and designing novel biomaterials.

Decellularized Extracellular Matrices and Cardiac Differentiation: Study on Human Amniotic Fluid-Stem Cells.

Cell therapy with a variety of stem populations is increasingly being investigated as a promising regenerative strategy for cardiovascular (CV) diseases. Their combination with adequate scaffolds represents an improved therapeutic approach. Recently, several biomaterials were investigated as scaffolds for CV tissue repair, with decellularized extracellular matrices (dECMs) arousing increasing interest for cardiac tissue engineering applications. The aim of this study was to analyze whether dECMs support the cardiac differentiation of CardiopoieticAF stem cells. These perinatal stem cells, which can be easily isolated without ethical or safety limitations, display a high cardiac differentiative potential. Differentiation was previously achieved by culturing them on Matrigel, but this 3D scaffold is not transplantable. The identification of a new transplantable scaffold able to support CardiopoieticAF stem cell cardiac differentiation is pivotal prior to encouraging translation of in vitro studies in animal model preclinical investigations. Our data demonstrated that decellularized extracellular matrices already used in cardiac surgery (the porcine CorTMPATCH and the equine MatrixPatchTM) can efficiently support the proliferation and cardiac differentiation of CardiopoieticAF stem cells and represent a useful cellular scaffold to be transplanted with stem cells in animal hosts.

Spare Parts from Discarded Materials: Fetal Annexes in Regenerative Medicine.

One of the main aims in regenerative medicine is to find stem cells that are easy to obtain and are safe and efficient in either an autologous or allogenic host when transplanted. This review provides an overview of the potential use of the fetal annexes in regenerative medicine: we described the formation of the annexes, their immunological features, the new advances in the phenotypical characterization of fetal annexes-derived stem cells, the progressions obtained in the analysis of both their differentiative potential and their secretoma, and finally, the potential use of decellularized fetal membranes. Normally discarded as medical waste, the umbilical cord and perinatal tissue not only represent a rich source of stem cells but can also be used as a scaffold for regenerative medicine, providing a suitable environment for the growth and differentiation of stem cells.

Cell-protection mechanism through autophagy in HGFs/S. mitis co-culture treated with Chitlac-nAg.

Silver-based products have been proven to be effective in retarding and preventing bacterial growth since ancient times. In the field of restorative dentistry, the use of silver ions/nanoparticles has been explored to counteract bacterial infections, as silver can destroy bacterial cell walls by reacting with membrane proteins. However, it is also cytotoxic towards eukaryotic cells, which are capable of internalizing nanoparticles. In this work, we investigated the biological effects of Chitlac-nAg, a colloidal system based on a modified chitosan (Chitlac), administered for 24-48 h to a co-culture of primary human gingival fibroblasts and Streptococcus mitis in the presence of saliva, developed to mimic the microenvironment of the oral cavity. We sought to determine its efficiency to combat oral hygiene-related diseases without affecting eukaryotic cells. Cytotoxicity, reactive oxygen species production, apoptosis induction, nanoparticles uptake, and lysosome and autophagosome metabolism were evaluated. In vitro results show that Chitlac-nAg does not exert cytotoxic effects on human gingival fibroblasts, which seem to survive through a homoeostasis mechanism involving autophagy. That suggests that the novel biomaterial Chitlac-nAg could be a promising tool in the field of dentistry.

Adhesion of human gingival fibroblasts/Streptococcus mitis co-culture on the nanocomposite system Chitlac-nAg.

Composite materials are increasingly used as dental restoration. In the field of biomaterials, infections remain the main reason of dental devices failure. Silver, in the form of nanoparticles (AgNPs), ions and salt, well known for its antimicrobial properties, is used in several medical applications in order to avoid bacterial infection. To reduce both bacterial adhesion to dental devices and cytotoxicity against eukaryotic cells, we coated BisGMA/TEGDMA methacrylic thermosets with a new material, Chitlac-nAg, formed by stabilized AgNPs with a polyelectrolyte solution containing Chitlac. Here we analyzed the proliferative and adhesive ability of human gingival fibroblasts (HGFs) on BisGMA/TEGDMA thermosets uncoated and coated with AgNPs in a coculture model system with Streptococcus mitis. After 48 h, HGFs well adhered onto both surfaces, while S. mitis cytotoxic response was higher in the presence of AgNPs coated thermosets. After 24 h thermosets coated with Chitlac as well as those coated with Chitlac-nAg exerted a minimal cytotoxic effect on HGFs, while after 48 h LDH release raised up to 20 %. Moreover the presence of S. mitis reduced this release mainly when HGFs adhered to Chitlac-nAg coated thermosets. The reduced secretion of collagen type I was significant in the presence of both surfaces with the co-culture system even more when saliva is added. Integrin ß1 localized closely to cell membranes onto Chitlac-nAg thermosets and PKCα translocated into nuclei. These data confirm that Chitlac-nAg have a promising utilization in the field of restorative dentistry exerting their antimicrobial activity due to AgNPs without cytotoxicity for eukaryotic cells.

Cytotoxicity and apoptosis induction by e-cigarette fluids in human gingival fibroblasts.

OBJECTIVES: Electronic cigarettes (e-cigarettes) are generally acknowledged as a safer alternative to the use of combusted tobacco products. Nevertheless, there are increasing conflicting claims concerning the effect of these novel industrial products on the health of e-cigarettes users. The aim of this work was to investigate the effects of the liquids of e-cigarettes on human gingival fibroblasts (HGFs) and to compare the effects of nicotine-containing fluid to the fluid itself. MATERIALS AND METHODS: HGFs were treated with different concentrations (0-5 mg/mL) of fluids of e-cigarettes for different times (0-72 h) and cytotoxicity was analyzed by MTT assay. Fluids were administered also after being vaped (e.g., warmed into the cartomizer). Apoptosis occurrence and Bax expression were evaluated by flow cytometry; ROS production was analyzed by fluorescence optical microscopy. RESULTS: Both nicotine-containing and nicotine-free fluids induced an increased ROS production after 24 h, along with an increased Bax expression, followed by apoptosis occurrence after 48 h of exposure. CONCLUSIONS: The cytotoxicity exerted on HGFs by e-cigarettes fluids is not entirely ascribable to nicotine. Since the e-cigarettes are advertised as a safer alternative to traditional ones, especially for the possibility of "smoking" nicotine-free fluids, further studies are necessary to clarify the mechanism involved in the occurrence of cytotoxicity exerted by such compounds. CLINICAL RELEVANCE: Our results suggest a role for e-cigarette fluids in the pathogenesis of oral diseases, such as periodontitis.

2-Substituted-4,7-dihydro-4-ethylpyrazolo[1,5-a]pyrimidin-7-ones alleviate LPS-induced inflammation by modulating cell metabolism via CD73 upon macrophage polarization.

Macrophage polarization towards the M1 phenotype under bacterial product-related exposure (LPS) requires a rapid change in gene expression patterns and cytokine production along with a metabolic rewiring. Metabolic pathways and redox reactions are such tightly connected, giving rise to an area of research referred to as immunometabolism. A role in this context has been paid to the master redox-sensitive regulator Nuclear factor erythroid 2-related factor 2 (Nrf2) and to the 5'-ectonucleotidase CD73, a marker related to macrophage metabolism rearrangement under pro-inflammatory conditions. In this light, a cell model of LPS-stimulated macrophages has been established and nine 4,7-dihydro-4-ethylpyrazolo[l,5-a]pyrimidin-7-ones with a potential anti-inflammatory effect have been administered. Our data highlight that two selected compounds (namely, 5 and 8) inhibit the LPS-induced Nrf2 nuclear translocation and ameliorate the activity rate of the antioxidant enzyme catalase. Additionally, the pyridine-containing compound (8) promotes the shift from the pro-inflammatory immunophenotype M1 to the pro-resolving M2 one, by downregulating CD80 and iNOS and by enhancing CD163 and TGFß1 expression. Most importantly, CD73 is modulated by these compounds as well as the lactate production. Our data demonstrate that pyrazolo[l,5-a]pyrimidine derivatives are effective as anti-inflammatory compounds. Furthermore, these pyrazolo[l,5-a]pyrimidines exert their action via CD73-related signaling and modulation of cell metabolism of activated macrophages.

The effect of a silver nanoparticle polysaccharide system on streptococcal and saliva-derived biofilms.

In this work, we studied the antimicrobial properties of a nanocomposite system based on a lactose-substituted chitosan and silver nanoparticles: Chitlac-nAg. Twofold serial dilutions of the colloidal Chitlac-nAg solution were both tested on Streptococcus mitis, Streptococcus mutans, and Streptococcus oralis planktonic phase and biofilm growth mode as well as on saliva samples. The minimum inhibitory and bactericidal concentrations of Chitlac-nAg were evaluated together with its effect on sessile cell viability, as well as both on biofilm formation and on preformed biofilm. In respect to the planktonic bacteria, Chitlac-nAg showed an inhibitory/bactericidal effect against all streptococcal strains at 0.1% (v/v), except for S. mitis ATCC 6249 that was inhibited at one step less. On preformed biofilm, Chitlac-nAg at a value of 0.2%, was able to inhibit the bacterial growth on the supernatant phase as well as on the mature biofilm. For S. mitis ATCC 6249, the biofilm inhibitory concentration of Chitlac-nAg was 0.1%. At sub-inhibitory concentrations, the Streptococcal strains adhesion capability on a polystyrene surface showed a general reduction following a concentration-dependent-way; a similar effect was obtained for the metabolic biofilm activity. From these results, Chitlac-nAg seems to be a promising antibacterial and antibiofilm agent able to hinder plaque formation.

PKC-δ signalling pathway is involved in H9c2 cells differentiation.

H9c2 are rat heart embryonic myoblasts, with skeletal muscle properties, which terminally differentiate by fusing and forming multinucleated myotubes. Here we investigated the possible involvement of Protein Kinases C (PKCs) in H9c2 cell differentiation and explored the interplay of these enzymes both with reactive oxygen species (ROS), upstream physiological mediators of cell differentiation, and with nitric oxide (NO), downstream target of PKC activation, known for being involved in apoptosis induction in differentiated myoblasts. Cells were induced to differentiate (6 days) under low serum culture conditions and assayed for the expression of cell cycle (cyclin A) and differentiation markers (morphology and myogenin). Both ROS and in vivo production of NO were found increased after 6 days of differentiation, when the activation of PKC-δ isoform was 14-fold increased compared with the undifferentiated control cells. The parallel analysis of apoptotic features demonstrated a small increase in Annexin-V+ cells and a concomitant increase in PARP cleavage and Bax expression. Interestingly, a reduced percentage of differentiated cells was obtained both in the presence of Rottlerin, a highly selective PKC-δ pharmacologic inhibitor, and, moreover, with the use of PKC-δ siRNA technology, further supporting the involvement of PKC-δ in switching on the events related to skeletal muscle myoblast differentiation.

Curcuma longa Hepatotoxicity: A Baseless Accusation. Cases Assessed for Causality Using RUCAM Method.

Curcuma longa is a perennial herb that belongs to the Zingiberaceae family. To date, literature includes more than 11.000 scientific articles describing all its beneficial properties. In the last 3 decades various surveys by the U.S. Food and Drug Administration (FDA) concluded that curcumin, the most active ingredient of the drug, is a "generally safe" compound with strong anti-oxidant effects. Curcuma longa was introduced in the daily diet by ayurvedic teachers due to its beneficial effects on health. Nonetheless, recently several reports, from the various global surveillance systems on the safety of plant products, pointed out cases of hepatotoxicity linked to consumption of food supplements containing powdered extract and preparations of Curcuma longa. The latest trend is the use of Curcuma longa as a weight-loss product in combination with piperine, which is used to increase its very low systemic bioavailability. Indeed, only 20 mg piperine, one of the alkaloids found in black pepper (Piper nigrum), assumed at the same time with 2 g curcumin increased 20-fold serum curcumin bioavailability. This combination of natural products is now present in several weight loss supplements containing Curcuma longa. The enhanced drug bioavailability caused by piperine is due to its potent inhibition of drug metabolism, being able to inhibit human P-glycoprotein and CYP3A4, while it interferes with UDP-glucose dehydrogenase and glucuronidation activities in liver. While only few cases of hepatotoxicity, assessed using Roussel Uclaf Causality Assessment Method (RUCAM) method, from prolonged intake of piperine and curcumin have been reported, it would be reasonable to speculate that the suspected toxicity of Curcuma longa could be due to the concomitant presence of piperine itself. Hence, not only there is the need of more basic research to understand the etiopathology of curcumin-related hepatotoxicity and of the combination curcumin-piperine, but human trials will be necessary to settle this dispute.

Curcuma longa aqueous extract: A potential solution for the prevention of corneal scarring as a result of pterygium surgical excision (Review).

Curcumin has been used since ancient times as a treatment for a wide range of pathologies. For centuries, it has been considered to be an effective aid for common human diseases. Curcuma longa has been reported to possess various beneficial properties and actions, including anti­inflammatory, proapoptotic, antiangiogenic and cortisone­like actions. Pterygium is a degenerative disorder of the conjunctiva indicative of a strong inflammatory condition that requires surgical treatment, which often results in disfiguring sclerocorneal scars. The delay in the healing of superficial corneal wounds caused by topical administration of light­cortisone results in improved restoration of corneal functions and anatomy compared with physiological healing processes. The present review is focused on the medicinal properties of curcumin, the main component of Curcuma longa extract, in particular its strong cortisone­like effect, and its potential use for the prevention and treatment of sclerocorneal scars resulting from pterygium surgical excision.

Redox Control of IL-6-Mediated Dental Pulp Stem-Cell Differentiation on Alginate/Hydroxyapatite Biocomposites for Bone Ingrowth.

Composites and porous scaffolds produced with biodegradable natural polymers are very promising constructs which show high biocompatibility and suitable mechanical properties, with the possibility to be functionalized with growth factors involved in bone formation. For this purpose, alginate/hydroxyapatite (Alg/HAp) composite scaffolds using a novel production design were successfully developed and tested for their biocompatibility and osteoconductive properties in vitro. Redox homeostasis is crucial for dental pulp stem cell (DPSC) differentiation and mineralized matrix deposition, and interleukin-6 (IL-6) was found to be involved not only in immunomodulation but also in cell proliferation and differentiation. In the present study, we evaluated molecular pathways underlying the intracellular balance between redox homeostasis and extracellular matrix mineralization of DPSCs in the presence of composite scaffolds made of alginate and nano-hydroxyapatite (Alg/HAp). Prostaglandin-2 (PGE2) and IL-6 secretion was monitored by ELISA assays, and protein expression levels were quantified by Western blotting. This work aims to demonstrate a relationship between DPSC capacity to secrete a mineralized matrix in the presence of Alg/HAp scaffolds and their immunomodulatory properties. The variation of the molecular axis Nrf2 (nuclear factor erythroid 2-related factor 2)/PGE2/IL-6 suggests a tight intracellular balance between oxidative stress responses and DPSC differentiation in the presence of Alg/HAp scaffolds.

Chitlac-coated Thermosets Enhance Osteogenesis and Angiogenesis in a Co-culture of Dental Pulp Stem Cells and Endothelial Cells.

Dental pulp stem cells (DPSCs) represent a population of stem cells which could be useful in oral and maxillofacial reconstruction. They are part of the periendothelial niche, where their crosstalk with endothelial cells is crucial in the cellular response to biomaterials used for dental restorations. DPSCs and the endothelial cell line EA.hy926 were co-cultured in the presence of Chitlac-coated thermosets in culture conditions inducing, in turn, osteogenic or angiogenic differentiation. Cell proliferation was evaluated by 3-[4,5-dimethyl-thiazol-2-yl-]-2,5-diphenyl tetrazolium bromide (MTT) assay. DPSC differentiation was assessed by measuring Alkaline Phosphtase (ALP) activity and Alizarin Red S staining, while the formation of new vessels was monitored by optical microscopy. The IL-6 and PGE2 production was evaluated as well. When cultured together, the proliferation is increased, as is the DPSC osteogenic differentiation and EA.hy926 vessel formation. The presence of thermosets appears either not to disturb the system balance or even to improve the osteogenic and angiogenic differentiation. Chitlac-coated thermosets confirm their biocompatibility in the present co-culture model, being capable of improving the differentiation of both cell types. Furthermore, the assessed co-culture appears to be a useful tool to investigate cell response toward newly synthesized or commercially available biomaterials, as well as to evaluate their engraftment potential in restorative dentistry.

PI3-K/Akt-dependent activation of cAMP-response element-binding (CREB) protein in Jurkat T leukemia cells treated with TRAIL.

We recently demonstrated the activation of phosphatidylinositol 3-kinase (PI3-K/Akt) survival pathway in Jurkat T leukemia cells known for their sensitivity to the tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL)/Apo2L cytotoxic action. The present investigation was done to elucidate the role of cAMP-response element-binding (CREB) protein in this system. Jurkat T cells were treated with 100-1,000 ng/ml TRAIL for time intervals up to 24 h in the presence or absence of selective pharmacologic inhibitors of PI3-K/Akt (LY294002) or p38 MAPK (SB253580) pathways. Upon TRAIL treatment, a dose-dependent increase in the percentage of apoptotic cells as well as in caspase-3 activity was observed. A further enhancement of apoptotic cell death was obtained with the use of CREB1 siRNA technology, as demonstrated by flow cytometry. Western blot analysis showed a high constitutive level of CREB phosphorylation at Ser(133) in Jurkat T cells under normal serum culture conditions. Under low serum culture conditions, an early (within 1 h) and transient increase in CREB phosphorylation was detected in response to both TRAIL doses and reduced upon pre-treatment with LY294002 or SB253580, demonstrating the PI3-K/Akt- and p38 MAPK-dependency of this effect. The parallel analysis in immune fluorescence demonstrated the nuclear translocation of the phosphorylated form upon treatment with 100 ng/ml TRAIL, whereas the immune labeling was mainly detectable in the cytoplasm compartment upon the higher more cytotoxic dose. These results let us hypothesize that CREB activation can be an important player in the complex cross-talk among pro- and anti-apoptotic pathways in this peculiar cell model.

Alginate/Hydroxyapatite-Based Nanocomposite Scaffolds for Bone Tissue Engineering Improve Dental Pulp Biomineralization and Differentiation.

Tissue engineering is widely recognized as a promising approach for bone repair and reconstruction. Several attempts have been made to achieve materials that must be compatible, osteoconductive, and osteointegrative and have mechanical strength to provide a structural support. Composite scaffolds consisting in biodegradable natural polymers are very promising constructs. Hydroxyapatite (HAp) can support alginate as inorganic reinforcement and osteoconductive component of alginate/HAp composite scaffolds. Therefore, HAp-strengthened polymer biocomposites offer a solid system to engineer synthetic bone substitutes. In the present work, HAp was incorporated into an alginate solution and internal gelling was induced by addition of slowly acid-hydrolyzing D-gluconic acid delta-lactone for the direct release of calcium ions from HAp. It has been previously demonstrated that alginate-based composites efficiently support adhesion of cancer bone cell lines. Human dental pulp stem cells (DPSCs) identified in human dental pulp are clonogenic cells capable of differentiating in multiple lineage. Thus, this study is aimed at verifying the mineralization and differentiation potential of human DPSCs seeded onto scaffolds based on alginate and nano-hydroxyapatite. For this purpose, gene expression profile of early and late mineralization-related markers, extracellular matrix components, viability parameters, and oxidative stress occurrence were evaluated and analyzed. In summary, our data show that DPSCs express osteogenic differentiation-related markers and promote calcium deposition and biomineralization when growing onto Alg/HAp scaffolds. These findings confirm the use of Alg/HAp scaffolds as feasible composite materials in tissue engineering, being capable of promoting a specific and successful tissue regeneration as well as mineralized matrix deposition and sustaining natural bone regeneration.