Moxifloxacin-Mediated Killing of Mycobacterium tuberculosis Involves Respiratory Downshift, Reductive Stress, and Accumulation of Reactive Oxygen Species.

Moxifloxacin is central to treatment of multidrug-resistant tuberculosis. Effects of moxifloxacin on the Mycobacterium tuberculosis redox state were explored to identify strategies for increasing lethality and reducing the prevalence of extensively resistant tuberculosis. A noninvasive redox biosensor and a reactive oxygen species (ROS)-sensitive dye revealed that moxifloxacin induces oxidative stress correlated with M. tuberculosis death. Moxifloxacin lethality was mitigated by supplementing bacterial cultures with an ROS scavenger (thiourea), an iron chelator (bipyridyl), and, after drug removal, an antioxidant enzyme (catalase). Lethality was also reduced by hypoxia and nutrient starvation. Moxifloxacin increased the expression of genes involved in the oxidative stress response, iron-sulfur cluster biogenesis, and DNA repair. Surprisingly, and in contrast with Escherichia coli studies, moxifloxacin decreased expression of genes involved in respiration, suppressed oxygen consumption, increased the NADH/NAD+ ratio, and increased the labile iron pool in M. tuberculosis. Lowering the NADH/NAD+ ratio in M. tuberculosis revealed that NADH-reductive stress facilitates an iron-mediated ROS surge and moxifloxacin lethality. Treatment with N-acetyl cysteine (NAC) accelerated respiration and ROS production, increased moxifloxacin lethality, and lowered the mutant prevention concentration. Moxifloxacin induced redox stress in M. tuberculosis inside macrophages, and cotreatment with NAC potentiated the antimycobacterial efficacy of moxifloxacin during nutrient starvation, inside macrophages, and in mice, where NAC restricted the emergence of resistance. Thus, NADH-reductive stress contributes to moxifloxacin-mediated killing of M. tuberculosis, and the respiration stimulator (NAC) enhances lethality and suppresses the emergence of drug resistance.

Clinicoepidemiologic Features of Chronic Urticaria in Patients with versus without Subclinical Helicobacter pylori Infection: A Cross-Sectional Study of 150 Patients.

BACKGROUND: The Helicobacter pylori infection is linked to chronic urticaria in nearly 60% of patients. We studied clinicoepidemiologic features in patients with chronic urticaria with and without H. pylori infection. METHODS: Endoscopic antral biopsy for the rapid urease test (RUT) and histopathology, and serum IgG ELISA for H. pylori infection were performed in 150 patients (male:female ratio 1:2.4) of chronic urticaria aged 18-68 years. Clinicoepidemiologic features including age, gender, age of onset and duration, frequency and distribution of wheals, urticaria severity score, and systemic symptoms were analyzed in patients with and without H. pylori. The results of serum IgG ELISA for H. pylori were compared with 106 age- and gender-matched healthy adult controls. RESULTS: The RUT in 84 patients (56%), histopathology in 76 patients (50.6%), and H. pylori IgG ELISA in 94 patients (62.6%) were positive. H. pylori IgG ELISA was positive only in 35 (33%) controls, suggesting that chronic urticaria patients were more likely to have asymptomatic H. pylori infection than normal controls. Although not statistically significant, patients with H. pylori had a higher mean urticaria severity score, number of urticaria/angioedema episodes per year, and involvement of more body sites, particularly the scalp, palms, and soles. The constitutional or gastrointestinal symptoms were statistically higher in patients with H. pylori infection than those without it. CONCLUSION: A subset of chronic urticaria patients appears to have asymptomatic H. pylori infection. However, its implications in chronicity, recurrences, the severity of urticaria, other systemic manifestations, and management remains conjectural in view of 33% of controls also having positive H. pylori ELISA and the endemicity of infection in developing countries.

Human mesenchymal stem cells: New sojourn of bacterial pathogens.

Tuberculosis (TB), caused by Mycobacterium tuberculosis (M. tuberculosis), is the leading infectious disease which claims one human life every 15-20s globally. The persistence of this deadly disease in human population can be attributed to the ability of the bacterium to stay in latent form. M. tuberculosis possesses a plethora of mechanisms not only to survive latently under harsh conditions inside the host but also modulate the host immune cells in its favour. Various M. tuberculosis gene families have also been described to play a role in this process. Recently, human bone marrow derived mesenchymal stem cells (MSCs) have been reported as a niche for dormant M. tuberculosis. MSCs possess abilities to alter the host immune response. The bacterium finds this self-renewal and immune privileged nature of MSCs very favourable not only to modulate the host immune system, with some help from its own genes, but also to avoid the external drug pressure. We suggest that the MSCs not only provide a resting place for M. tuberculosis but could also, by virtue of their intrinsic ability to disseminate in the body, explain the genesis of extra-pulmonary TB. A similar exploitation of stem cells by other bacterial pathogens is a distinct possibility. It may be likely that other intracellular bacterial pathogens adopt this strategy to 'piggy-back' on to ovarian stem cells to ensure vertical transmission and successful propagation to the next generation.

Gene cooption in mycobacteria and search for virulence attributes: comparative proteomic analyses of Mycobacterium tuberculosis, Mycobacterium indicus pranii and other mycobacteria.

Tuberculosis (TB), caused by Mycobacterium tuberculosis, is a leading infectious disease taking one human life every 15s globally. Mycobacterium undergoes reductive evolution; the ancestors have bigger genome size and rich in metabolic pathways. Mycobacterium indicus pranii (MIP) is placed much above Mycobacterium tuberculosis (M.tb) in evolutionary scale and is a non-pathogenic, saprophytic mycobacterium. Our in silico comparative proteomic analyses of virulence factors of M.tb and their homologs in 12 different Mycobacterial species, including MIP, point toward gene cooption as an important mechanism in evolution of mycobacteria. We propose that adaptive changes in niche factors of non-pathogenic mycobacterium, together with novel gene acquisitions, are key players in the evolution of pathogenicity. Antigenic analyses between M.tb and MIP highlighted the importance of PE/PPE family in host immunomodulation, further supporting the likely potential of MIP as an effective vaccine against TB.

Comparative genomic and proteomic analyses of PE/PPE multigene family of Mycobacterium tuberculosis H37Rv and H37Ra reveal novel and interesting differences with implications in virulence.

Tuberculosis, caused by Mycobacterium tuberculosis, remains a leading infectious disease taking one human life every 15 s globally. The two well-characterized strains H(37)Rv and H(37)Ra, derived from the same parental strain M. tuberculosis H(37), show dramatically different pathogenic phenotypes. PE/PPE gene family, comprising of 176 open reading frames and present exclusively in genus Mycobacterium, accounts for ∼10% of the M. tuberculosis genome. Our comprehensive in silico analyses of PE/PPE family of H(37)Ra and virulent H(37)Rv strains revealed genetic differences between these strains in terms of several single nucleotide variations and InDels and these manifested in changes in physico-chemical properties, phosphorylation sites, and protein: protein interacting domains of the corresponding proteomes. Similar comparisons using the 13 sigma factor genes, 36 members of the mammalian cell entry family, 13 mycobacterial membrane protein large family members and 11 two-component signal transduction systems along with 5 orphaned response regulators and 2 orphaned sensor kinases failed to reveal very significant difference between H(37)Rv and H(37)Ra, reinforcing the importance of PE/PPE genes. Many of these changes between H(37)Rv and H(37)Ra can be correlated to differences in pathogenesis and virulence of the two strains.

Cysteine desulfurase (IscS)-mediated fine-tuning of bioenergetics and SUF expression prevents Mycobacterium tuberculosis hypervirulence.

Iron-sulfur (Fe-S) biogenesis requires multiprotein assembly systems, SUF and ISC, in most prokaryotes. M. tuberculosis (Mtb) encodes a complete SUF system, the depletion of which was bactericidal. The ISC operon is truncated to a single gene iscS (cysteine desulfurase), whose function remains uncertain. Here, we show that MtbΔiscS is bioenergetically deficient and hypersensitive to oxidative stress, antibiotics, and hypoxia. MtbΔiscS resisted killing by nitric oxide (NO). RNA sequencing indicates that IscS is important for expressing regulons of DosR and Fe-S-containing transcription factors, WhiB3 and SufR. Unlike wild-type Mtb, MtbΔiscS could not enter a stable persistent state, continued replicating in mice, and showed hypervirulence. The suf operon was overexpressed in MtbΔiscS during infection in a NO-dependent manner. Suppressing suf expression in MtbΔiscS either by CRISPR interference or upon infection in inducible NO-deficient mice arrests hypervirulence. Together, Mtb redesigned the ISC system to "fine-tune" the expression of SUF machinery for establishing persistence without causing detrimental disease in the host.

Substantial tumor regression in prostate cancer patient with extensive skeletal metastases upon Immunotherapy (APCEDEN): A case report.

RATIONALE: Prostate cancer along with colorectal and lung cancers accounts for 42% of cancer cases in men globally. It is the first cancer indication for which the use of active immunotherapy, Sipuleucel-T (Provenge) was granted by the FDA in 2010. This study presents a case of prostate carcinoma and the tumour remission observed after administration of a personalised Dendritic cell vaccine (APCEDEN). PATIENT CONCERNS: A 58 years old Caucasian male diagnosed with prostate carcinoma with GLEASON score 8. The patient had previously been diagnosed with Renal Cell Carcinoma (RCC) in 1996 and had undergone nephrectomy of the right kidney. PET CT scan revealed multiple intensely PSMA avid lesions noted in both lobes of the prostate gland with SUVmax -28.3 and the prostate gland measuring 3.2 × 3.2 cm displaying maximum dimensions. DIAGNOSIS: FNAC followed by PETCT confirmed CA Prostate and further supported by increased serum PSA level. INTERVENTIONS: The patient underwent personalised Dendritic Cell Immunotherapy APCEDEN regimen of six doses biweekly, in a time frame of 3 months were given both via intravenous and intradermal route. Six months post completion of APCEDEN, the patient was administered 6 booster shots for 6 months. OUTCOMES: Progressive remission of carcinoma was observed along with reduction in PSA and Testosterone levels. PET CT showed decline in PSMA avidity by 50% with SUVmax -14.0 and normal size and shape of prostate gland. LESSONS: Prostate carcinoma is the second most common cancer in men with majority of them exhibiting locally advanced disease. Apparently 20% to 30% of them are categorized as relapsed cases after various therapeutic interventions. Modulating immune system is an emerging therapy termed as Immunotherapy and potentiates the killing cancer cells via immune activation. Interestingly, prostate cancer is slow growing and it provides the scope and time to mount an anti-tumor response which makes it an attractive target for immunotherapy. This case study demonstrates the efficacy of APCEDEN Immunotherapy regimen resulting in a significant disease remission benefiting the patient.

Substantial remission of prostate adenocarcinoma with dendritic cell therapy APCEDEN® in combination with chemotherapy.

Of the most prevalent solid tumors with advanced disease, prostate and ovarian cancer and non-small cell lung carcinoma have the fewest therapeutic options. Herein, we report the case of a 63-year-old male with metastatic prostate adenocarcinoma showing substantial remission post-administration of personalized dendritic cell-based vaccine APCEDEN® in combination with chemotherapeutic drug Mitoxantrone. Therapeutic response displayed an interesting clinical correlation validated by PET scan images showing decreased fluorodeoxyglucose (FDG) avidity in the prostate gland, reduced skeletal metastases further established by the drop in serum Prostate Specific Antigen (PSA) levels and expression of immune assessment markers (IFN-γ, Tregs, neutrophil lymphocyte ratio and platelet lymphocyte ratio). This case demonstrates the potential efficacy of dendritic cell immunotherapy, showing a potent antitumor activity by enhancing the host immune responses, and improving quality of life.

Targeting redox heterogeneity to counteract drug tolerance in replicating Mycobacterium tuberculosis.

The capacity of Mycobacterium tuberculosis (Mtb) to tolerate multiple antibiotics represents a major problem in tuberculosis (TB) management. Heterogeneity in Mtb populations is one of the factors that drives antibiotic tolerance during infection. However, the mechanisms underpinning this variation in bacterial population remain poorly understood. Here, we show that phagosomal acidification alters the redox physiology of Mtb to generate a population of replicating bacteria that display drug tolerance during infection. RNA sequencing of this redox-altered population revealed the involvement of iron-sulfur (Fe-S) cluster biogenesis, hydrogen sulfide (H2S) gas, and drug efflux pumps in antibiotic tolerance. The fraction of the pH- and redox-dependent tolerant population increased when Mtb infected macrophages with actively replicating HIV-1, suggesting that redox heterogeneity could contribute to high rates of TB therapy failure during HIV-TB coinfection. Pharmacological inhibition of phagosomal acidification by the antimalarial drug chloroquine (CQ) eradicated drug-tolerant Mtb, ameliorated lung pathology, and reduced postchemotherapeutic relapse in in vivo models. The pharmacological profile of CQ (C max and AUClast) exhibited no major drug-drug interaction when coadministered with first line anti-TB drugs in mice. Our data establish a link between phagosomal pH, redox metabolism, and drug tolerance in replicating Mtb and suggest repositioning of CQ to shorten TB therapy and achieve a relapse-free cure.

The PGRS Domain of Mycobacterium tuberculosis PE_PGRS Protein Rv0297 Is Involved in Endoplasmic Reticulum Stress-Mediated Apoptosis through Toll-Like Receptor 4.

The genome of Mycobacterium tuberculosis, the causal organism of tuberculosis (TB), encodes a unique protein family known as the PE/PPE/PGRS family, present exclusively in the genus Mycobacterium and nowhere else in the living kingdom, with largely unexplored functions. We describe the functional significance of the PGRS domain of Rv0297, a member of this family. In silico analyses revealed the presence of intrinsically disordered stretches and putative endoplasmic reticulum (ER) localization signals in the PGRS domain of Rv0297 (Rv0297PGRS). The PGRS domain aids in ER localization, which was shown by infecting macrophage cells with M. tuberculosis and by overexpressing the protein by transfection in macrophage cells followed by activation of the unfolded protein response, as evident from increased expression of GRP78/GRP94 and CHOP/ATF4, leading to disruption of intracellular Ca2+ homeostasis and increased nitric oxide (NO) and reactive oxygen species (ROS) production. The consequent activation of the effector caspase-8 resulted in apoptosis of macrophages, which was Toll-like receptor 4 (TLR4) dependent. Administration of recombinant Rv0297PGRS (rRv0297PGRS) also exhibited similar effects. These results implicate a hitherto-unknown role of the PGRS domain of the PE_PGRS protein family in ER stress-mediated cell death through TLR4. Since this protein is already known to be present at later stages of infection in human granulomas it points to the possibility of it being employed by M. tuberculosis for its dissemination via an apoptotic mechanism.IMPORTANCE Apoptosis is generally thought to be a defense mechanism in protecting the host against Mycobacterium tuberculosis in early stages of infection. However, apoptosis during later stages in lung granulomas may favor the bacterium in disseminating the disease. ER stress has been found to induce apoptosis in TB granulomas, in zones where apoptotic macrophages accumulate in mice and humans. In this study, we report ER stress-mediated apoptosis of host cells by the Rv0297-encoded PE_PGRS5 protein of M. tuberculosis exceptionally present in the pathogenic Mycobacterium genus. The PGRS domain of Rv0297 aids the protein in localizing to the ER and induces the unfolded protein response followed by apoptosis of macrophages. The effect of the Rv0297PGRS domain was found to be TLR4 dependent. This study presents novel insights on the strategies employed by M. tuberculosis to disseminate the disease.

Complete remission of rare adenocarcinoma of the oropharynx with APCEDEN® (dendritic cell-based vaccine): a case report.

APCEDEN ® is an autologous monocyte-derived dendritic cell-based immunotherapy. A 58-year-old man with adenocarcinoma of oropharynx shows complete remission after receiving APCEDEN ® in conjunction with Geftinib validated by reduction in size, whereas Gefitinib alone lead to disease progression.

Immune modulation by dendritic-cell-based cancer vaccines.

The interplay between host immunity and tumour cells has opened the possibility of targeting tumour cells by modulation of the human immune system. Cancer immunotherapy involves the treatment of a tumour by utilizing the recombinant human immune system components to target the pro-tumour microenvironment or by revitalizing the immune system with the ability to kill tumour cells by priming the immune cells with tumour antigens. In this review, current immunotherapy approaches to cancer with special focus on dendritic cell (DC)-based cancer vaccines are discussed. Some of the DC-based vaccines under clinical trials for various cancer types are highlighted. Establishing tumour immunity involves a plethora of immune components and pathways; hence, combining chemotherapy, radiation therapy and various arms of immunotherapy, after analysing the benefits of individual therapeutic agents, might be beneficial to the patient.

A retrospective analysis comparing APCEDEN® dendritic cell immunotherapy with best supportive care in refractory cancer.

AIM: A retrospective survival benefit analysis of APCEDEN®, APAC BIOTECH Pvt Ltd 69, Jacranda Marg, DLF PHASE II, Gurugram, Haryana, India, an autologous dendritic cell-based product for management of refractory solid malignancies, was performed in comparison with a control group. METHODS: Subjects (retrospective data) whose survival data, geographical region, age, gender, ECOG performance status and stage of disease that could be matched with the treatment group were considered for analysis. RESULTS: The analysis suggests a significant survival benefit of 199 days for the APCEDEN therapy treatment group when compared with the control group (356 vs 157 days). The event-free survival time of APCEDEN therapy was 439 days in patients who demonstrated an objective response at first evaluation as per immune-related response criteria. CONCLUSION: APCEDEN demonstrated highly convincing survival benefits when compared with the control group.

Comparative analyses of nonpathogenic, opportunistic, and totally pathogenic mycobacteria reveal genomic and biochemical variabilities and highlight the survival attributes of Mycobacterium tuberculosis.

UNLABELLED: Mycobacterial evolution involves various processes, such as genome reduction, gene cooption, and critical gene acquisition. Our comparative genome size analysis of 44 mycobacterial genomes revealed that the nonpathogenic (NP) genomes were bigger than those of opportunistic (OP) or totally pathogenic (TP) mycobacteria, with the TP genomes being smaller yet variable in size--their genomic plasticity reflected their ability to evolve and survive under various environmental conditions. From the 44 mycobacterial species, 13 species, representing TP, OP, and NP, were selected for genomic-relatedness analyses. Analysis of homologous protein-coding genes shared between Mycobacterium indicus pranii (NP), Mycobacterium intracellulare ATCC 13950 (OP), and Mycobacterium tuberculosis H37Rv (TP) revealed that 4,995 (i.e., ~95%) M. indicaus pranii proteins have homology with M. intracellulare, whereas the homologies among M. indicus pranii, M. intracellulare ATCC 13950, and M. tuberculosis H37Rv were significantly lower. A total of 4,153 (~79%) M. indicus pranii proteins and 4,093 (~79%) M. intracellulare ATCC 13950 proteins exhibited homology with the M. tuberculosis H37Rv proteome, while 3,301 (~82%) and 3,295 (~82%) M. tuberculosis H37Rv proteins showed homology with M. indicus pranii and M. intracellulare ATCC 13950 proteomes, respectively. Comparative metabolic pathway analyses of TP/OP/NP mycobacteria showed enzymatic plasticity between M. indicus pranii (NP) and M. intracellulare ATCC 13950 (OP), Mycobacterium avium 104 (OP), and M. tuberculosis H37Rv (TP). Mycobacterium tuberculosis seems to have acquired novel alternate pathways with possible roles in metabolism, host-pathogen interactions, virulence, and intracellular survival, and by implication some of these could be potential drug targets. IMPORTANCE: The complete sequence analysis of Mycobacterium indicus pranii, a novel species of Mycobacterium shown earlier to have strong immunomodulatory properties and currently in use for the treatment of leprosy, places it evolutionarily at the point of transition to pathogenicity. With the purpose of establishing the importance of M. indicus pranii in providing insight into the virulence mechanism of tuberculous and nontuberculous mycobacteria, we carried out comparative genomic and proteomic analyses of 44 mycobacterial species representing nonpathogenic (NP), opportunistic (OP), and totally pathogenic (TP) mycobacteria. Our results clearly placed M. indicus pranii as an ancestor of the M. avium complex. Analyses of comparative metabolic pathways between M. indicus pranii (NP), M. tuberculosis (TP), and M. intracellulare (OP) pointed to the presence of novel alternative pathways in M. tuberculosis with implications for pathogenesis and survival in the human host and identification of new drug targets.