Induction of macrophagic and granulocytic differentiation of murine bone marrow progenitor cells by 1,25-dihydroxyvitamin D3

Vitamin D Enhances Hematoma Clearance and Neurologic Recovery in Intracerebral Hemorrhage

BACKGROUND

Erythrophagocytosis by reparative monocyte-derived macrophage contributes to hematoma clearance and neurological recovery after intracerebral hemorrhage (ICH). Vitamin D (VitD) is a neuroprotective hormone and regulates the differentiation of monocyte-derived macrophage from monocytes. In this study, we examined the effects of VitD supplementation on monocyte-derived macrophage and hematoma clearance in rodent with ICH.

METHODS

Neurobehavioral functions and hematoma volume were assessed using a collagenase injection model in both young- and middle-aged mice with or without VitD treatment given 2 hours post-ICH induction. We used flow cytometry to analyze CD36 expression and macrophage and undifferentiated monocyte cell numbers during in vivo erythrophagocytosis in collagenase and autologous blood injection models. Western blot analysis and immunofluorescence were used to assess the expression levels of the PPAR-γ (peroxisome proliferator-activated receptor γ)-CD36 axis and CD206. A macrophage differentiation study was conducted on murine bone marrow-derived monocytes.

RESULTS

VitD promoted neurological recovery and facilitated hematoma clearance in both young- and middle-aged mice after ICH. Within the perihematomal region, mature macrophages, rather than undifferentiated monocytes, expressed higher levels of CD36 in driving erythrocyte clearance. VitD increased the macrophage number but decreased the monocyte number and elevated the levels of CD36 and PPAR-γ in the brain. In vitro, VitD accelerated the differentiation of reparative macrophages from bone marrow-derived monocytes.

CONCLUSIONS

VitD promotes reparative macrophage differentiation, facilitates hematoma clearance, and improves neurobehavioral performance in mice with ICH, suggesting that VitD should be further examined as a potentially promising treatment for ICH.

Vitamin D: A Pleiotropic Hormone with Possible Psychotropic Activities

BACKGROUND

After the recognition of the efficacy of cod-liver oil in rickets at the end of the eighteenth century, and the isolation and synthesis of the liposoluble vitamin D in 1931, its mode of actions and functions were deeply explored. Biochemical studies permitted to identify five forms of vitamin D, called D1, D2, D3, D4 and D5, differing in ultrastructural conformation and origin, with vitamin D2 (ergocalciferol) and D3 (cholecalciferol) representing the active forms. In the last decades especially, a constantly increasing bulk of data highlighted how vitamin D could regulate several activities and processes.

AIMS

The aim of the present paper was to review and comment on the literature on vitamin D, with a focus on its possible role in the pathophysiology of neuropsychiatric disorders.

DISCUSSION

Available literature indicates that vitamin D regulates a variety of processes in humans and in the central nervous system. Vitamin D deficiency is associated with an enhanced pro-inflammatory state, and formation of Aβ oligomers that might contribute to the cognitive decline typical of the elderly age and, perhaps, dementia. More in general, vitamin D is supposed to play a crucial role in neuroinflammation processes that are currently hypothesized to be involved in the pathophysiology of different psychiatric disorders, such as major depression, bipolar disorders, obsessive-compulsive disorders and psychosis.

CONCLUSION

It is conceivable that vitamin D supplementation might pave the way towards "natural" treatments of a broad range of neuropsychiatric disorders, or at least be useful to boost response to psychotropic drugs in resistant cases.

Vitamin D in HIV-Infected Patients

Observational studies have noted very high rates of low 25(OH)D (vitamin D) levels in both the general and HIV-infected populations. In HIV-infected patients, low 25(OH)D levels are likely a combination of both traditional risk factors and HIV-specific and antiretroviral therapy-specific contributors. Because of this unique risk profile, HIV-infected persons may be at greater risk for low 25(OH)D levels and frank deficiency and/or may respond to standard repletion regimens differently than HIV-uninfected patients. Currently, the optimal repletion and maintenance dosing regimens for HIV-infected patients remain unknown, as do potential benefits of supplementation that may be unique to the HIV-infected population. This paper reviews data published on HIV infection and vitamin D health in adults over the last year.

Colonic vitamin D metabolism: implications for the pathogenesis of inflammatory bowel disease and colorectal cancer

In epidemiological studies serum levels below 30 nM of 25-OHD(3), the precursor of the active vitamin D metabolite 1,25-(OH)(2)D(3), were consistently associated with incidence of colorectal cancer. The active vitamin D metabolite possesses antimitotic, prodifferentiating and proapoptotic capacity in vivo and in vitro. The intestinal autocrine/paracrine vitamin D system, which is the main source of local 1,25-(OH)(2)D(3) plays a critical role in maintaining both mucosal immunity and normal growth of epithelial cells. It has been hypothesized that the VDR-mediated signaling antagonizing TNF-α and IL-6 receptor-activated pro-inflammatory and proliferative intracellular pathways, may prevent development of IBD and colitis-associated colorectal cancer. Conversely, any situation that impairs the efficiency of the 1,25-(OH)(2)D(3)/VDR signaling system at the level of the gut mucosa, e.g. vitamin D insufficiency, may increase risk for the development of IBD and colorectal cancer. Therefore, not only adequate serum levels of the precursor 25-OHD(3) are essential, but also optimal expression of the 1α-hydroxylating enzyme CYP27B1. The 1,25-(OH)(2)D(3) catabolizing hydroxylase CYP24A1 is increasingly expressed during colon cancer progression, indicating that colonocytes are released from normal growth control by the steroid hormone. Securing adequate levels of calcitriol by inhibition of catabolism and support of 1α-hydroxylation by calcium, phytoestrogens and folate could be a valid approach to control, at least in part, IBD and CRC pathogenesis.

Treatment of secondary hyperparathyroidism in kidney disease: what we know and do not know about use of calcimimetics and vitamin D analogs

There is a growing understanding of the pathophysiology of secondary hyperparathyroidism (SHPT) and a recent emergence of new agents for SHPT treatment in patients with advanced kidney disease. At the same time, appreciation that mineral metabolic derangements promote vascular calcification and contribute to excess mortality, along with recognition of potentially important “non-classical” actions of vitamin D, have prompted the nephrology community to reexamine the use of various SHPT treatments, such as activated vitamin D sterols, phosphate binders, and calcimimetics. In this review, the evidence for treatment of SHPT with calcimimetics and vitamin D analogs is evaluated, with particular consideration given to recent clinical trials that have reported encouraging findings with cinacalcet use. Additionally, several controversies in the pathogenesis and treatment of SHPT are explored. The proposition that calcitriol deficiency is a true pathological state is challenged, the relative importance of the vitamin D receptor and the calcium sensing receptor in parathyroid gland function is summarized, and the potential relevance of non-classical actions of vitamin D for patients with advanced renal disease is examined. Taken collectively, the balance of evidence now supports a treatment paradigm in which calcimimetics are the most appropriate primary treatment for SHPT in the majority of end stage renal disease patients, but which nevertheless acknowledges an important role for modest doses of activated vitamin D sterols.

Natural feline coronavirus infection: differences in cytokine patterns in association with the outcome of infection

Natural and experimental feline coronavirus (FCoV) infection leads to systemic viral spread via monocyte-associated viraemia and induces systemic proliferation of monocytes/macrophages. In the majority of naturally infected animals, FCoV infection remains subclinical and is associated with generalised B and T cell hyperplasia, but no other pathological findings. A minority of cats, however, develop feline infectious peritonitis (FIP), a fatal systemic granulomatous disease. This is generally accompanied by B and T cell depletion. The obvious functional differences of lymphatic tissues in FCoV-infected cats with and without FIP suggest that they contribute to the outcome of FCoV infection. This study attempted to evaluate the functional changes in haemolymphatic tissues after natural FCoV infection, with special emphasis on the magnitude, phenotype and function of the monocyte/macrophage population. The spleen, mesenteric lymph nodes and bone marrow from naturally FCoV-infected cats with and without FIP and specific pathogen-free (SPF) control cats were examined for the quantity and activation state of monocytes/macrophages both by immunohistology and by quantitative real time PCR for the transcription of interleukin (IL)-1β, IL-6, IL-10, IL-12 p40, tumour necrosis factor (TNF), granulocyte colony stimulating factor (G-CSF), macrophage-CSF (M-CSF) and GM-CSF. Compared to cats with FIP, FCoV-infected cats without FIP exhibited significantly higher IL-10 levels in the spleen and significantly lower levels of IL-6, G- and M-CSF in mesenteric lymph nodes. In cats with FIP, however, IL-12 p40 levels were significantly lower in lymphatic tissues in comparison to both SPF cats and FCoV-infected cats without FIP. In comparison to SPF cats, FIP cats had significantly higher IL-1β levels and lower TNF levels in mesenteric lymph nodes and lower M-CSF levels in the spleen. Findings indicate that FCoV-infected cats which do not develop FIP are able to mount an effective FCoV-specific immune response and can avoid excessive macrophage activation and FIP, possibly by upregulation of IL-10 production. Development of FIP, however, might be due to a lack of IL-12 which inhibits an effective cellular immune response and allows for monocyte/macrophage activation and the development of FIP.

Vitamin D and calcium deficits predispose for multiple chronic diseases

There is evidence from both observational studies and clinical trials that calcium malnutrition and hypovitaminosis D are predisposing conditions for various common chronic diseases. In addition to skeletal disorders, calcium and vitamin D deficits increase the risk of malignancies, particularly of colon, breast and prostate gland, of chronic inflammatory and autoimmune diseases (e.g. insulin-dependent diabetes mellitus, inflammatory bowel disease, multiple sclerosis), as well as of metabolic disorders (metabolic syndrome, hypertension). The aim of the present review was to provide improved understanding of the molecular and cellular processes by which deficits in calcium and vitamin D cause specific changes in cell and organ functions and thereby increase the risk for chronic diseases of different aetiology. 1,25-Dihydroxyvitamin D(3) and extracellular Ca(++) are both key regulators of proliferation, differentiation and function at the cellular level. However, the efficiency of vitamin D receptor-mediated intracellular signalling is limited by the negative effects of hypovitaminosis D on extrarenal 25-hydroxyvitamin D-1alpha-hydroxylase activity and thus on the production of 1,25-dihydroxyvitamin D(3). Calcium malnutrition eventually causes a decrease in calcium concentration in extracellular fluid compartments, resulting in organ-specific modulation of calcium-sensing receptor activity. Hence, attenuation of signal transduction from the ligand-activated vitamin D receptor and calcium-sensing receptor seems to be the prime mechanism by which calcium and vitamin D insufficiencies cause perturbation of cellular functions in bone, kidney, intestine, mammary and prostate glands, endocrine pancreas, vascular endothelium, and, importantly, in the immune system. The wide range of diseases associated with deficits in calcium and vitamin D in combination with the high prevalence of these conditions represents a special challenge for preventive medicine.

NaF induces early differentiation of murine bone marrow cells along the granulocytic pathway but not the monocytic or preosteoclastic pathway in vitro

The stimulatory effects of sodium fluoride (NaF) on bone formation have been explained solely by its activation of osteoblasts. However, whether and how NaF acts on the osteoclast lineage is poorly understood. We previously found that NaF differentiates HL-60 cells to granulocytic cells. To further test this action, we have employed here primary cultures of progenitor cells derived from murine bone marrow. NaF at subtoxic concentrations (<0.5 mM) significantly up-regulated activities of several intracellular enzymes (lactate dehydrogenase, beta-glucuronidase, acid phosphatase), cellular reduction of nitroblue tetrazolium, and nitric oxide (NO) production; which are all accepted as general differentiation markers. NaF (<0.5 mM) also up-regulated granulocyte-specific markers (chloroacetate esterase, cell surface antigens [Mac-1, Gr-1]) but not any of the monocyte-specific markers (nonspecific esterase, cell surface antigens [F4/80, MOMA-2]). Although other general differentiation markers (phagocytosis, adhesion, appearance, nuclear:cytoplasmic ratio) were not appreciably influenced by NaF, essentially in support of our previous data from HL-60 cells, the present findings suggest that NaF induces early differentiation of bone marrow hemopoietic progenitor cells along the granulocytic pathway but not the monocytic pathway that is linked to osteoclast formation. Therefore, in addition to its potent stimulatory effects on osteoblastic bone formation, NaF applied to patients with osteoporosis could be expected to indirectly reduce osteoclastic bone resorption.

Antibody against surface-bound C5a peptidase is opsonic and initiates macrophage killing of group B streptococci

The capsular polysaccharides of group B streptococci (GBS) are a primary focus of vaccine development. Immunogenicity and long-lasting protection are best achieved by conjugating polysaccharides to a T-cell-dependent protein antigen. Streptococcal C5a peptidase (SCPB) is a conserved surface protein that is expressed by all streptococcal serotypes tested to date, and it is a possible carrier protein that could itself induce a protective immune response. Clearance of GBS from lungs, mucosal surfaces, or blood probably depends on the opsonophagocytic response of tissue-specific macrophages and polymorphonuclear leukocytes (PMNs). In this study, we examined the potential of antibody directed against SCPB from a serotype II strain to enhance the capacity of mouse bone marrow macrophages (from primary cultures) and human PMNs in whole blood to kill GBS in vitro. Our experiments demonstrated that Streptococcus serotypes Ia, Ib, II, III, and V, preopsonized with anti-SCPB antibody, were killed more rapidly by cultured macrophages and PMNs in whole blood than were nonopsonized GBS. The increased rate of killing was accompanied by an increased macrophage oxidative burst. Furthermore, opsonization was serotype transparent. Immunization with SCPB conjugated to capsular polysaccharide type III produced polysaccharide-specific antibodies. It is interesting that this antiserum promoted serotype-independent killing of streptococci. These data support the use of SCPB in a GBS polysaccharide conjugate vaccine. SCPB not only enhanced the immunogenicity of polysaccharide components of the vaccine, but it might also induce additional serotype-independent protective antibodies.

Characteristics of NaF-induced differentiation of HL-60 cells

Sodium fluoride (NaF) is known to stimulate osteoblastic bone formation, but little attention has been given to the possibility that NaF also affects bone resorption and the differentiation of osteoclastic progenitor cells. When human promyelocytic HL-60 cells were treated with NaF (0.5 mM, 0-4 days), cell proliferation was inhibited, and the addition of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) (10nM, 0-4 days) augmented this antiproliferative effect. NaF increased cellular reduction of nitroblue tetrazolium (NBT), and this effect was strongly augmented by 1,25(OH)2D3. In addition, NaF produced marked changes in cellular morphology, increased cellular adhesion to plastic, reduced the nuclear/cytoplasmic ratio, and increased cellular expression of chloroacetate esterase, but failed to alter cellular nonspecific esterase activity. Furthermore, NaF increased expression of CD11b and CD66b, and this stimulation was enhanced by adding 1,25(OH)2D3. The sum of these changes in classical promyelocytic cellular indices suggest: (1) that NaF stimulates the early stages of HL-60 differentiation toward a granulocyte-like cell and (2) that 1,25(OH)2D3 promotes these actions of NaF. Additional experiments aimed at further understanding the NaF-induced conversion of HL-60 cells identified further changes. NaF also increased cellular production of prostaglandin E2 (PGE2) and nitric oxide (NO) and induced expression of inducible nitric oxide synthase (iNOS); 1,25(OH)2D3 once again augmented these NaF-induced effects. Similarly, NaF stimulated the production of interleukin 1 alpha (IL-1 alpha), IL-6, and tumor necrosis factor-alpha, and 1,25(OH)2D3 again strongly enhanced these effects. Indomethacin completely blocked stimulation of NBT reduction, NO production, and iNOS expression induced by NaF plus 1,25(OH)2D3; adding exogenous PGE2 (0.1-10 ng/ml) to these indomethacin-blocked cultures dose-dependently restored NO production. These additional findings together with the observed slow onset (24-48 h) of NaF and 1,25(OH)2D3 interaction strongly suggest that 1,25(OH)2D3 acts as a cofactor with NaF primarily through interaction with an endogenous NaF-induced cyclo-oxygenase product(s), quite possibly PGE2 itself. Such a mechanism for NaF and 1,25(OH)2D3 interaction would be strongly analogous to the interaction we have recently demonstrated between 1,25(OH)2D3 and PGE1 on the differentiation of HL-60 cells.

1,25-Dihydroxyvitamin D3 promotes prostaglandin E1-induced differentiation of HL-60 cells

Human promyelocytic HL-60 cells can be induced by biochemical agents to differentiate in vitro towards divergent types of myelomonocytic cells. It has been reported that prostaglandin E1 (PGE1) can induce granulocytic differentiation and that 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) can induce monocytic differentiation. We have now examined the effects of these compounds, both alone and in combination, on HL-60 cell differentiation. PGE1 (1 microgram/ml) or 1,25(OH)2D3 (10 nM) each inhibited cell proliferation over 48-96 hours of treatment, but combined treatment with both agents was necessary to produce a strong inhibition. The percentage of HL-60 cells that can reduce nitroblue tetrazolium (NBT) (a characteristic index of early monocytic or granulocytic differentiation) increased 13-fold within 72 hours of PGE1 treatment, and 1,25(OH)2D3 produced a five-fold stimulation. However, combined treatment (PGE1 plus 1,25(OH)2D3) produced a dramatic 35-fold increase. HL-60 cells did not produce significant levels of nitric oxide (NO) before 48 hours in culture, and treatment with PGE1 or 1,25(OH)2D3 did not significantly increase cellular NO elaboration over control levels. However, combined treatment produced a striking 12-fold increase over control levels. Similarly, combined treatment was necessary to obtain the maximal time-dependent stimulation of cellular lactate dehydrogenase (LDH) activity (a marker of granulocytic differentiation) as well as acid phosphatase (ACP) activity. During this same period of time, PGE1, but not 1,25(OH)2D3, markedly stimulated cellular elaboration of interleukin (IL)-1 alpha, IL-6, and tumor necrosis factor (TNF)-alpha, and 1,25(OH)2D3 cotreatment strongly augmented these effects. Thus, combined treatment with 1,25(OH)2D3 plus PGE1 generally augmented the apparent conversion of these cells, producing synergistic (multiplicative) or additive effects. Furthermore, PGE1 induced within 48 hours the more general phenotypic changes classically associated with the differentiation of these cells: increased expression of chloroacetate esterase (ChAE) (a granulocytic marker), decreases in the nuclear/cytoplasmic ratio (characteristic of development beyond the promyelocyte/myelocyte stage), and major alterations in morphology from floating spherical cells to loosely adherent, elliptical polygons. 1,25(OH)2D3 had little effect itself on most of these parameters, but augmented the morphological changes induced by PGE1 treatment. Within 48 hours, the ability of these cells to reduce the tetrazolium salt WST-1, a general measure of cellular metabolic activity, was increased by PGE1, but not by 1,25(OH)2D3; however, the combination of 1,25(OH)2D3 and PGE1 again produced the strongest stimulation. Similarly, only PGE1 significantly reduced intracellular ATP levels, but combined treatments produced a more pronounced decrease. In summary, our findings suggest that PGE1, not 1,25(OH)2D3, is sufficient to promote rapid in vitro differentiation of HL-60 cells along the granulocyte pathway; however, the PGE1-induced conversion of these cells is markedly augmented by cotreatment with 1,25(OH)2D3. In addition, these converted HL-60 cells preferentially utilize the glycolytic pathway, rather than the citric acid cycle, for production of ATP, a metabolic characteristic that resembles that described for mature granulocytes.