An Expandable Mechanopharmaceutical Device (1): Measuring the Cargo Capacity of Macrophages in a Living Organism

PURPOSE

Clofazimine (CFZ) is an FDA-approved, poorly soluble small molecule drug that precipitates as crystal-like drug inclusions (CLDIs) which accumulate in acidic cytoplasmic organelles of macrophages. In this study, we considered CLDIs as an expandable mechanopharmaceutical device, to study how macrophages respond to an increasingly massive load of endophagolysosomal cargo.

METHODS

First, we experimentally tested how the accumulation of CFZ in CLDIs impacted different immune cell subpopulations of different organs. Second, to further investigate the mechanism of CLDI formation, we asked whether specific accumulation of CFZ hydrochloride crystals in lysosomes could be explained as a passive, thermodynamic equilibrium phenomenon. A cellular pharmacokinetic model was constructed, simulating CFZ accumulation driven by pH-dependent ion trapping of the protonated drug in the acidic lysosomes, followed by the precipitation of CFZ hydrochloride salt via a common ion effect caused by high chloride concentrations.

RESULTS

While lower loads of CFZ were mostly accommodated in lung macrophages, increased CFZ loading was accompanied by organ-specific changes in macrophage numbers, size and intracellular membrane architecture, maximizing the cargo storage capabilities. With increasing loads, the total cargo mass and concentrations of CFZ in different organs diverged, while that of individual macrophages converged. The simulation results support the notion that the proton and chloride ion concentrations of macrophage lysosomes are sufficient to drive the massive, cell type-selective accumulation and growth of CFZ hydrochloride biocrystals.

CONCLUSION

CLDIs effectively function as an expandable mechanopharmaceutical device, revealing the coordinated response of the macrophage population to an increasingly massive, whole-organism endophagolysosomal cargo load.

An Expandable Mechanopharmaceutical Device (2): Drug Induced Granulomas Maximize the Cargo Sequestering Capacity of Macrophages in the Liver

PURPOSE

Drug-induced liver injuries (DILI) comprise a significant proportion of adverse drug reactions leading to hospitalizations and death. One frequent DILI is granulomatous inflammation from exposure to harmful metabolites that activate inflammatory pathways of immune cells of the liver, which may act as a barrier to isolate the irritating stimulus and limit tissue damage.

METHODS

Paralleling the accumulation of CFZ precipitates in the liver, granulomatous inflammation was studied to gain insight into its effect on liver structure and function. A structural analog that does not precipitate within macrophages was also studied using micro-analytical approaches. Depleting macrophages was used to inhibit granuloma formation and assess its effect on drug bioaccumulation and toxicity.

RESULTS

Granuloma-associated macrophages showed a distinct phenotype, differentiating them from non-granuloma macrophages. Granulomas were induced by insoluble CFZ cargo, but not by the more soluble analog, pointing to precipitation being a factor driving granulomatous inflammation. Granuloma-associated macrophages showed increased activation of lysosomal master-regulator transcription factor EB (TFEB). Inhibiting granuloma formation increased hepatic necrosis and systemic toxicity in CFZ-treated animals.

CONCLUSIONS

Granuloma-associated macrophages are a specialized cell population equipped to actively sequester and stabilize cytotoxic chemotherapeutic agents. Thus, drug-induced granulomas may function as drug sequestering "organoids" -an induced, specialized sub-compartment- to limit tissue damage.

Detecting ordered small molecule drug aggregates in live macrophages: a multi-parameter microscope image data acquisition and analysis strategy

Following prolonged administration, certain orally bioavailable but poorly soluble small molecule drugs are prone to precipitate out and form crystal-like drug inclusions (CLDIs) within the cells of living organisms. In this research, we present a quantitative multi-parameter imaging platform for measuring the fluorescence and polarization diattenuation signals of cells harboring intracellular CLDIs. To validate the imaging system, the FDA-approved drug clofazimine (CFZ) was used as a model compound. Our results demonstrated that a quantitative multi-parameter microscopy image analysis platform can be used to study drug sequestering macrophages, and to detect the formation of ordered molecular aggregates formed by poorly soluble small molecule drugs in animals.

A far-red fluorescent probe for flow cytometry and image-based functional studies of xenobiotic sequestering macrophages

Clofazimine (CFZ) is an optically active, red-colored chemotherapeutic agent that is FDA approved for the treatment of leprosy and is on the World Health Organization's list of essential medications. Interestingly, CFZ massively accumulates in macrophages where it forms crystal-like drug inclusions (CLDIs) after oral administration of the drug in animals and humans. The analysis of the fluorescence spectra of CLDIs formed by resident tissue macrophages revealed that CFZ, when accumulated as CLDIs, undergoes a red shift in fluorescence excitation (from Ex: 540-570 to 560-600 nm) and emission (Em: 560-580 to 640-700 nm) signal relative to the soluble and free-base crystal forms of CFZ. Using epifluorescence microscopy, CLDI(+) cells could be identified, relative to CLDI(-) cells, based on a >3-fold increment in mean fluorescence signal at excitation 640 nm and emission at 670 nm. Similarly, CLDI(+) cells could be identified by flow cytometry, based on a >100-fold increment in mean fluorescence signal using excitation lasers at 640 nm and emission detectors >600 nm. CLDI's fluorescence excitation and emission was orthogonal to that of cell viability dyes such as propidium iodide and 4,6-diamidino-2-phenylindole dihydrochloride (DAPI), cellular staining dyes such as Hoechst 33342 (nucleus) and FM 1-43 (plasma membrane), as well as many other fluorescently tagged antibodies used for immunophenotyping analyses. In vivo, >85% of CLDI(+) cells in the peritoneal exudate were F4/80(+) macrophages and >97% of CLDI(+) cells in the alveolar exudate were CD11c(+). Most importantly, the viability of cells was minimally affected by the presence of CLDIs. Accordingly, these results establish that CFZ fluorescence in CLDIs is suitable for quantitative flow cytometric phenotyping analysis and functional studies of xenobiotic sequestering macrophages.

Interferon regulatory factor-1 in flagellin-induced reprogramming: potential protective role of CXCL10 in cornea innate defense against Pseudomonas aeruginosa infection

PURPOSE

We previously showed that pre-exposure of the cornea to Toll-like receptor (TLR)5 ligand flagellin induces strong protective innate defense against microbial pathogens and hypothesized that flagellin modulates gene expression at the transcriptional levels. Thus, we sought to determine the role of one transcription factor, interferon regulatory factor (IRF1), and its target gene CXCL10 therein.

METHODS

Superarray was used to identify transcription factors differentially expressed in Pseudomonas aeruginosa-challenged human corneal epithelial cells (CECs) with or without flagellin pretreatment. The expression of CXCL10, IRF1, LI-8(CXCL2), and IFNγ was determined by PCR, immunohistochemistry, Western/dot blotting, and/or ELISA. IRF1 knockout mice, CXCL10 and IFNγ neutralization, and NK cell depletion were used to define in vivo regulation and function of CXCL10. The severity of P. aeruginosa was assessed using clinical scoring, slit-lamp microscopy, bacterial counting, polymorphonuclear leukocytes (PMN) infiltration, and macrophage inflammatory protein 2/Chemokine (C-X-C motif) ligand 2 (MIP-2/CXCL2) expression.

RESULTS

Flagellin pretreatment drastically affected P. aeruginosa-induced IRF1 expression in human CECs. However, flagellin pretreatment augmented the P. aeruginosa-induced expression of Irf1 and its target gene Cxcl10 in B6 mouse corneas. Irf1 deficiency reduced infection-triggered CXCL10 expression, increased keratitis severity, and attenuated flagellin-elicited protection compared to values in wild-type (WT) controls. CXCL10 neutralization in the cornea of WT mice displayed pathogenesis similar to that of IRF1⁻/⁻ mice. IFNγ receptor neutralization and NK cell depletion prevented flagellin-augmented IRF1 and CXCL10 expression and increased the susceptibility to P. aeruginosa infection in mouse corneas.

CONCLUSIONS

IRF1 plays a role in the corneal innate immune response by regulating CXCL10 expression. IFNγ-producing NK cells augment the epithelial expression of IRF1 and CXCL10 and thus contribute to the innate defense of the cornea against P. aeruginosa infection.

Dendritic cell-epithelium interplay is a determinant factor for corneal epithelial wound repair

The functions of intraepithelial dendritic cells (DCs) are critical for mucosal innate and adaptive immunity, but little is known about the role of tissue-specific DCs in epithelial homeostasis and tissue repair. By using the epithelial debridement wound model and CD11c-diphtheria toxin receptor mice that express a CD11c promoter-driven diphtheria toxin receptor, we showed that DCs migrate along with the epithelial sheet to cover the wound and that local depletion of DCs resulted in a significant delay in epithelial wound closure. In response to wounding, migratory epithelia produce CXCL10, thymic stromal lymphopoietin, and IL-1β and its antagonist soluble IL-1 receptor antagonist (sIL-1Ra); depletion of corneal DCs reversed their elevated expressions to a different extent, suggesting a DC-mediated positive feedback loop in epithelial gene expression. Furthermore, both CXCL10 and thymic stromal lymphopoietin were localized in migratory epithelia, suggesting that epithelial cells play a key role in DC infiltration and activation in injured corneas. On the other hand, DC depletion resulted in suppressed epithelial AKT activation, increased cell apoptosis, and decreased polymorphonuclear leukocyte infiltration in the healing cornea. These results indicate that DCs and epithelium form a functional entity at mucosal surfaces for maintaining corneal homeostasis and for tissue repair.

Parenchymal and nonparenchymal cellular responses in human hepatic regeneration

To characterize cellular responses during hepatic regeneration, we examined 13 explant livers and 5 liver allografts by immunohistochemistry for cytokeratin 7, HepPar1, CD68, alpha-smooth muscle actin (alpha-SMA) and proliferating cell nuclear antigen as well as reticulin and Masson-trichrome staining. Within a week after liver damage, elongated CD68-positive cells were detected along the border of necrotic area. The number of alpha-SMA-positive cells was slightly increased along the sinusoids. Ductular proliferation or fibrosis was negligible. After one or two weeks, the size and number of CD68-positive cells were markedly increased. alpha-SMA-positive cells increased in number within lobules and portal tracts. Ductular proliferation occurred predominantly at the limiting plate or along the border of necrotic areas. After one month, necrotic parenchyma was replaced by many ductules, CD68-positive cells, alpha-SMA-positive cells. Nodules of regenerating hepatocytes and irregular fibrosis were diffusely present. Other nonparenchymal cells were not significantly changed. These observations indicate that chronological interaction between nonparenchymal and parenchymal cells occur during the course of human hepatic regeneration and suggest extensive porto-periportal fibrosis more than a few months after the onset of fulminant hepatitis is a major indicator of chronic functional impairment necessitating liver transplantation.

Overexpression of promyelocytic leukemia protein and alteration of PML nuclear bodies in early stage of hepatocarcinogenesis

Promyelocytic leukemia protein (PML) is a major component of PML nuclear bodies (PML NBs). Fusion of promyelocytic leukemia alpha gene (PML) with retinoic acid receptor gene with the t (15;17) translocation causes disassembly of PML NBs, leading to development of acute promyelocytic leukemia. In contrast, PML overexpression as well as different morphological changes of PML NBs were described in a few solid tumors. In this study, the expression of PML through the multistep hepatocarcinogenesis was analyzed in 95 cases of human hepatocellular carcinomas (HCCs) for comparison along with dysplastic nodules (DNs) and background liver cirrhosis (LC) or chronic hepatitis by immunohistochemistry and immunoblot. In addition, cases of HCCs were further evaluated according to their histologic grade and etiology. The amount of PML as well as the number and size of PML NBs increased gradually through the progression from LC, DNs to HCCs. The overexpression of PML in HCCs was much more closely associated with HBV infection than HCV infection or alcoholic liver disease. The PML expression, however, was not correlated with histologic grade of HCCs. These results suggest that PML is involved in the early stage of multistep hepatocarcinogenesis, and HBV infection may be associated with the overexpression of PML and the morphological alteration of PML NBs.

Primary synovial sarcoma of the kidney

The authors present two cases of primary synovial sarcoma of the kidney. Both patients had a mass in the upper part of the right kidney without any primary extrarenal neoplastic lesions. Grossly, the tumors were soft to rubbery masses measuring 5.5 cm and 5 cm in diameter, respectively. Histologically, both tumors were poorly differentiated synovial sarcoma. The lesions exhibited a hypercellular solid or lobular growth of round, oval, or short spindle cells in variably solid sheets, in intersecting fascicles, or in a haphazard fashion. Areas of solid aggregation or fascicles of the tumor cells alternating with hypocellular myxoid tissues, together with areas displaying a prominent hemangiopericytoma-like pattern, were found. Immunohistochemically, vimentin was diffusely positive and a few tumor cells were positive for cytokeratin, epithelial membrane antigen, and neurofilament. The tumor cells were negative for S- 100 protein, CD34, smooth muscle actin, and desmin, whereas CD56 and CD99 were positive. In both cases, reverse transcription-polymerase chain reaction using ribonucleic acid extracted from formalin-fixed, paraffin-embedded tissues detected SYT-SSX2 fusion gene transcripts, which are characteristic molecular findings of synovial sarcoma. One patient died 10 months after diagnosis. These tumors are unique cases of primary synovial sarcoma of the kidney confirmed by molecular study.

Inhibition of mast cell-mediated anaphylaxis by sochungryong-tang

According to traditional Asian philosophy, sochungryong-tang (S-Tang) is a prescription for treating exterior syndrome. In this study, we investigated the effect of S-Tang on mast cell-mediated anaphylaxis. S-Tang completely inhibited compound 48/80-induced systemic anaphylactic shock at a dose of 100 mg/kg. When S-Tang was given as pretreatment at concentrations ranging from 1 to 1000 mg/kg, the serum histamine levels induced by compound 48/80 were reduced in a dose-dependent manner. S-Tang inhibited the local anaphylaxis activated by anti-dinitrophenyl (DNP) IgE antibody, and also inhibited the histamine release from the rat peritoneal mast cells by compound 48/80 or anti-DNP IgE. These results indicate that S-Tang may contain substances with actions that inhibit mast cell degranulation.

Evidence that the 5'-end cap structure is essential for encapsidation of hepatitis B virus pregenomic RNA

Hepatitis B virus (HBV) replicates by reverse transcription of an RNA intermediate, the pregenomic RNA. The first step of HBV genome replication is the encapsidation of the pregenomic RNA encoding the encapsidation signal, termed epsilon, into the core particles, which is preceded by recognition and binding of HBV DNA polymerase to epsilon. The pregenomic RNA contains two identical epsilon elements due to its terminal redundancy: one near the 5' end and another near the 3' end. Despite the fact that both epsilon elements have an identical sequence, only the 5' epsilon, but not the 3' epsilon, is functional for encapsidation. To understand the molecular nature of this position effect, we made a series of lacZ RNA expression plasmids which contain the epsilon element at various positions from the 5' end of the transcripts. Following transfection, the lacZ RNAs in cytoplasmic core particles were measured by RNase protection assay for encapsidation. The results indicated that the lacZ RNAs with epsilon positioned up to 65 nucleotides from the 5' end were encapsidated, whereas the lacZ RNAs with epsilon positioned further downstream were not. Interestingly, the cap-free lacZ RNA transcribed by T7 RNA polymerase was not encapsidated, implying that the 5' cap structure is required for encapsidation of the pregenomic RNA. We hypothesized that HBV DNA polymerase must somehow recognize the cap structure and/or its associated factors, as well as the 5' epsilon, for encapsidation to occur.

Nuclear matrix of calreticulin in hepatocellular carcinoma

Nuclear matrix protein profiles of malignant cells vary from their normal counterparts. By two-dimensional gel electrophoresis, we analyzed nuclear matrix proteins in 11 hepatocellular carcinomas and compared them with corresponding non-neoplastic liver tissue. Although the compositions were mostly similar, several peptides were noted predominantly in the former. The most prominent one was an acidic protein of apparent Mr 62,000, which was identified to be calreticulin upon NH2-terminal amino acid sequencing. By immunoblotting, calreticulin was confirmed to be present abundantly in the nuclear matrix fraction of carcinomas but not in that of the nonmalignant liver tissue. Interestingly, the total content of calreticulin was similar between them. By immunofluorescence microscopy, evident nuclear immunostaining was detected in carcinomas. Calreticulin was also found to be in the nuclear matrices of various carcinoma cell lines. We conclude that calreticulin is a component of the nuclear matrix. The formation and/or expansion of the calreticulin-nuclear matrix may be related to the activated cell growth.

Fibrosing cholestatic hepatitis: a report of three cases

Fibrosing cholestatic hepatitis is an aggressive and usually fatal form of viral hepatitis in immunosuppressed patients. We report three cases of fibrosing cholestatic hepatitis in various clinical situations. Case 1 was a 50-year-old man who underwent a liver transplant for hepatitis B virus (HBV)-associated liver cirrhosis. Two and a half years after the transplant, he complained of fever and jaundice, and liver enzymes were slightly elevated. Serum HBsAg was positive. Case 2 was a 30-year-old man in an immunosuppressed state after chemotherapy for acute lymphoblastic leukemia. He was a HBV carrier. Liver enzymes and total bilirubin were markedly elevated. Case 3 was a 50-year-old man who underwent renal transplantation as a known HBV carrier. One year after the transplant, jaundice developed abruptly, but liver enzymes were not significantly elevated. Microscopically lobules were markedly disarrayed, showing ballooning degeneration of hepatocytes, prominent pericellular fibrosis, and marked canalicular or intracytoplasmic cholestasis. Portal inflammation was mild, but interphase activity was definite and cholangiolar proliferation was prominent. Hepatocytes were diffusely positive for HBsAg and HBcAg in various patterns. Patients died of liver failure within 1 to 3 months after liver biopsy in spite of anti-viral treatment.

Clinicopathologic characteristics of replication error-positive gastric carcinoma

Microsatellite instability (MI), an expansion or contraction of microsatellites, is a manifestation of replication errors (RERs) that is recognized as performing an important role in carcinogenesis in a proportion of gastric carcinomas. We analyzed 96 cases of sporadic gastric carcinomas for the occurrence of MI in BAT-26 and other six microsatellite loci. Gastric carcinomas with BAT-26 alteration demonstrated a higher proportion of unstable loci in other examined microsatellites than did gastric carcinomas without BAT-26 alteration. We classified gastric carcinomas with BAT-26 alteration as RER+ and compared the RER status with their clinicopathologic features. Ten (10.4%) of 96 gastric carcinomas showed RERs: 2 (7.7%) of 26 early gastric carcinomas and 8 (11.4%) of 70 advanced gastric carcinomas were RER+. RER+ gastric carcinomas were significantly associated with older age, elevated gross type (Borrmann Type 2 or EGC IIa), expanding growth pattern (Ming's classification), and minimal desmoplasia. Although statistically not significant, RER+ gastric carcinomas showed more frequent intestinal type (Lauren's classification), more antral involvement, and lower lymph node metastasis than did RER- gastric carcinomas. There was no association between RER status and intratumoral lymphocyte infiltration or histologic differentiation. In conclusion, RER+ gastric carcinomas demonstrated distinct clinicopathologic features, and BAT-26 was a useful marker for assessing the RER status of gastric carcinomas.

Primary myxoid leiomyoma of the liver

We describe a case of hepatic leiomyoma in a 41-year-old woman who complained of abdominal discomfort due to a right upper quadrant abdominal mass. A computed tomographic scan revealed a large hepatic mass with unusual cystic change. Light and electron microscopic findings and an immunohistochemical study demonstrated diffuse and scattered proliferation of smooth muscle cells in a myxoid matrix. In contrast to previously reported cases of primary leiomyoma of the liver, the present tumor developed in a patient without an immunosuppressive condition. To the best of our knowledge, this is the first reported case of primary "myxoid" leiomyoma of the liver.

Fine needle aspiration diagnosis of malignant mixed tumor (carcinosarcoma) arising in pleomorphic adenoma of the salivary gland. A case report

BACKGROUND

True malignant mixed tumor (carcinosarcoma), composed of carcinoma and sarcoma components, is rare in salivary gland neoplasms. Even rarer is a true malignant mixed tumor arising in the pleomorphic adenoma of the salivary gland.

CASE

A 64-year-old male was admitted with left pharyngeal pain. Head and neck magnetic resonance imaging revealed a left parapharyngeal mass; fine needle aspiration (FNA) cytology through the oral cavity was performed.

CONCLUSION

The aspirate presented a mixture of large, pleomorphic, vacuolated, single or multinucleated cells in a mucoid matrix and clusters of adenocarcinoma cells. Additionally, occasional benign glandular cells were noted. A cytologic diagnosis of malignant mixed tumor arising in the pleomorphic adenoma of the deep lobe of the parotid gland was made and confirmed by the surgically resected specimen.

Diagnostic pitfalls of Merkel cell carcinoma and dramatic response to chemotherapy

Merkel cell carcinoma (MCC) is an unusual malignant tumor that arises from neuroendocrine cells with features of epithelial differentiation. We describe a MCC patient with unusual clinical, histopathological, and immunohistochemical features. Although the microscopic, immunohistochemical, and ultrastructural characteristics of MCC have been well defined, diagnostic difficulties remain, particularly in distinguishing it from lymphoma involving the skin, as suggested by our case. This is an unusual case in which dense lymphoid infiltration masked the true tumor. All the immunohistochemical markers of MCC except neuron-specific enolase (NSE) were negative. The dramatic response to primary chemotherapy was also very noteworthy.

Primary pulmonary sarcoma with morphologic features of biphasic synovial sarcoma: a case report

We report an unusual primary case of pulmonary sarcoma that developed in the lung of a 36-year-old woman. The tumor had histologic, immunologic and ultrastructural features identical to those of biphasic synovial sarcoma of the soft tissue. It consisted of an intimate admixture of cytokeratin and epithelial membrane antigen(EMA)-positive neoplastic epithelial cells and vimentin-positive fibroblast-like spindle cells with areas of hyalinization. The patient had a lobectomy and showed no evidence of recurrence or tumor at other sites 15 months after surgery. This case is an useful addition to the small number of published reports on pulmonary synovial sarcoma. The distinctive features of this neoplasm allow it to be different from other types of primary and metastatic malignancies in the lung.

Assessment of reducibility of ileocolic intussusception in children: usefulness of color Doppler sonography

PURPOSE

To assess the diagnostic usefulness of ultrasonography (US) in intussusception in children and determine whether color Doppler sonography (CDS) can indicate bowel viability and help in prediction of reducibility.

MATERIALS AND METHODS

US was used to examine 176 children in whom the presence of intussusception was clinically suspected. CDS was performed in 64 patients with 65 cases of intussusception proved with US.

RESULTS

The positive US findings were confirmed with air enema; the negative findings, with air enema in 46 patients and clinical follow-up in 66 patients (100% specificity and sensitivity). CDS indicated blood flow in 62 of 65 cases of intussusception; pneumatic reduction was achieved in 58 (94%) of these 62 cases. Four patients (6%) underwent manual reduction of viable bowel; three patients (5%) who had no color Doppler signal underwent segmental resection. The difference in reduction rates based on blood flow was statistically significant (P = .0008).

CONCLUSION

US is sensitive and specific in the diagnosis of intussusception, and CDS is a promising predictor of bowel viability.