Morphological Lineage Research Articles

Promyelocytic leukemia protein (PML) and stem cells: from cancer to pluripotency

The promyelocytic leukemia protein (PML) is the core organizer of cognate nuclear bodies (PML-NBs). Through physical interaction or modification of diverse protein clients, PML-NBs regulate a multitude of - often antithetical- biological processes such as antiviral and stress response, inhibition of cell proliferation and autophagy, and promotion of apoptosis or senescence. Although PML was originally recognized as a tumor-suppressive factor, more recent studies have revealed a "double-faced" agent role for PML. Indeed, PML displayed tumor cell pro-survival and pro-migratory functions via inhibition of migration suppressing molecules or promotion of transforming growth factor beta (TGF-β) mediated Epithelial-Mesenchymal Transition (EMT) that may promote cancer cell dissemination. In this line, PML was found to correlate with poor patient prognosis in distinct tumor contexts. Furthermore, in the last decade, a number of publications have implicated PML in the physiology of normal or cancer stem cells (CSCs). Promyelocytic leukemia protein activates fatty acid oxidation (FAO), a metabolic mechanism required for the asymmetric divisions and maintenance of hematopoietic stem cells (HSCs). In embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs), PML is required for maintenance of the naïve and acquisition of the induced pluripotency state, respectively. Correspondingly, PML ablation causes significant morphological gene expression and lineage choice changes. In this review, we focus on the mechanisms orchestrated by PML and PML-NBs in cancer and healthy stem cells, from cell physiology to the regulation of chromatin dynamics.

Clinicopathological features of differentiated-type dysplasia of the esophagus

Objective: To investigate the clinicopathological features of differentiated-type (squamous) dysplasia of the esophagus. Methods: A total of 184 cases of esophageal differentiated-type dysplasia were collected retrospectively at People's Liberation Army Joint Logistics Support Force 989 Hospital (formerly 152 Hospital), and Beijing Chaoyang Hospital, Capital Medical University, China from 2016 to 2019. Their histological characteristics and immunophenotypes were analyzed, and related literature was reviewed. Results: The median age of the 184 patients was 65 years (range 39-83 years), while the ratio of men to women was 1.7∶1.0. There were 17 cases in the upper esophagus, 143 in the middle esophagus and 24 in the lower esophagus. The median diameter of the dysplasia was 15 mm (range 2-50 mm). According to the Paris classification, 2 cases were 0-Ⅰ, 25 cases were 0-Ⅱa, 70 cases were 0-Ⅱb, 74 cases were 0-Ⅱb and 0-Ⅱc and 13 cases were 0-Ⅱc. Macroscopically, the lesional mucosa was reddish with rough surface and white moss; capillary abnormality was found on narrow-band imaging. Histologically, dysplastic cells had distinct features of squamous epithelium, with abundant eosinophilic cytoplasm, round to irregular nuclei, coarse chromatin, obvious nucleolus, and conspicuous mitoses. The cellularity was increased, the arrangement of cells was disordered, and the polarity of cells in basal layer was lost. When the dysplasia did not completely spread to the whole layer of squamous epithelium, a clear boundary was often formed between the dysplasia and the normal epithelium above it. The neoplastic epithelial protrusions often grew toward the lamina propria and were accompanied by conspicuous inflammatory cell reaction at its frontal edge. Sometimes, abnormal mature single epithelial cells or cell clusters infiltrated into the lamina propria. There were high-grade dysplasia of the common type and superficial invasive squamous cell carcinoma in 98 cases of differentiated-type dysplasia. Immunohistochemical staining showed that the mutation rate of TP53 was 47.7% (53/111). The median of Ki-67 labeling index was 50.0% (range 10%-80%), while that of basal tumor cells was 12/HPF (range 3-65/HPF). The abnormal distribution pattern of Ki-67 was seen in 111 (100%) cases. According to the initial pathological diagnosis, there were 16 cases of low-grade intraepithelial neoplasia, 37 cases of atypical epithelial cells and 131 cases of high-grade intraepithelial neoplasia and superficial invasive squamous cell carcinoma. Conclusions: The morphology of differentiated-type dysplasia of the esophagus is unique. Characteristics of highly differentiated dysplastic cells suggest that they may represent a differentiated type in the morphological lineage of esophageal squamous (high-grade) dysplasia. When the knowledge of the lesion is insufficient, it is easy to be misdiagnosed or missed in pathologic examination.

Hybridization of Two Species of Japanese Toads, Bufo torrenticola and Bufo japonicus formosus, in the Central Part of Japan.

Interspecific hybridization between two species of Japanese toads, Bufo torrenticola (Bt) and Bufo japonicus formosus (Bjf), was not thought to have occurred due to the differences in their spawning habitats, although their hybridization was reported by previous research in a limited area. Such hybridization could have pivotal effects, such as genetic admixture, on Bt, which has a limited distribution and habitat. In this study, to clarify the details of hybridization, a total of 192 individuals were collected from multiple parapatric regions and an only Bjf allopatric region and analyzed based on morphology, mtDNA sequences, and nuclear DNA microsatellite loci. Each individual was identified based on morphological type and mtDNA lineage, and two mismatched combinations, Bt or an intermediate morphological type and the Bjf mtDNA lineage, were detected. In particular, the combination of Bt type and Bjf lineage was dominant in parapatric regions, and it was considered that asymmetric hybridization in which Bjf became a matriline had occurred. In addition, a Bayesian clustering method based on the microsatellite loci was conducted to detect a genetic admixture of the two toad species. Individuals representing a combination of the Bt type and Bjf lineage in the parapatric regions were largely assigned to the Bt cluster or equally to both clusters. These results indicate that backcross with Bt has been repeated, and therefore the traits of Bt might be maintained in this study.

Phylogeographical history of the Olive Woodpecker Dendropicos griseocephalus, a species widely distributed across Africa

Few studies have quantified the extent of genetic differentiation within widely distributed polytypic African bird species with disjunct ranges. Current knowledge indicates that high levels of genetic differentiation are found for such lineages but generalization of the pattern requires further comparisons with other co‐distributed taxa. We assessed the extent of phylogeographical structure across the range of the Olive Woodpecker Dendropicos griseocephalus using mitochondrial and nuclear intron data. The Olive Woodpecker occupies the forests of Central (Dendropicos griseocephalus ruwenzori) and Eastern (Dendropicos g. kilimensis) Africa, with a disjunct morphological lineage (Dendropicos g. griseocephalus) occurring in southern Africa. Each of the subspecies lineages can be diagnosed using morphology. Phylogenetic analyses of our sequence data recovered three monophyletic lineages with kilimensis sister to ruwenzori, and griseocephalus as sister to the clade uniting these two taxa. Molecular species delimitation methods and estimates of gene flow under the isolation‐with‐migration model suggest that the clade uniting the central and eastern subspecies may be recognized as distinct at the species level from the nominate subspecies, which is restricted to southern Africa. We conclude that D. griseocephalus (Boddaert, 1783) and D. ruwenzori (Sharpe, 1902) (including subspecies kilimensis) should be considered full species. The biogeographical pattern we uncover for the Olive Woodpecker differs from that of other co‐distributed widespread species both in terms of the order of sequence divergence of lineages occupying different areas of endemism in Africa, and in the timing of divergence, being younger (0.5–0.7 mya BP) than that recovered for the co‐distributed Square‐tailed Drongo Dicrurus ludwigii (0.9–1.6 mya BP).

New Agraeciini species from the Eastern Arc Mountains, East Africa(Orthoptera: Tettigoniidae; Conocephalinae; Agraeciini).

Eleven new Agraeciini species are described. Six species of Afroanthracites are new to science from the North and South Pare, the West and East Usambara, the Udzungwa Mountains of Tanzania, and the Taita Hills of Kenya. The two Afroanthracites Hemp Ingrisch, 2013 species from the Pare Mountains, A. guttatus n. sp. and A. maculatus n. sp., and A. magamba n. sp., from Magamba Forest Reserve in the West Usambara Mountains are morphologically closely related to each other and form a morphological lineage with the already described species from the West Usambara Mountains (A. discolor Hemp, Ingrisch Ünal, 2013 and A. pseudodiscolor Hemp, 2015) and A. pommeri n. sp. from the Taita Hills of Kenya. A. lineatus n. sp. from Lutindi Forest Reserve in the East Usambara Mountains has its morphologically closest relative in A. jagoi Ünal Hemp, 2013 endemic to the Mazumbai Forest Reserve of the West Usambara Mountains while A. montium (Sjöstedt, 1910) from the Kilimanjaro/Meru area, A. inopinatus n. sp. from the South Pare Mountains and A. usambaricus (Sjöstedt, 1913) from the West Usambara Mountains form another morphological lineage. Morphological traits like the shape of the last abdominal tergite in males, the male cerci and the colour pattern suggest at least two lineages reflecting dispersal of the ancestors at a time when forest connected the mountain ranges in the past during climatic fluctuations. In the genus Afroagraecia Ingrisch Hemp, 2013 new species were collected on Zanzibar and in Kazimzumbwi Forest Reserve, the Udzungwa and Nguru Mountains. Distribution patterns and the morphology suggest recent speciation patterns of Afroagraecia in the Eastern Arc Mountains and along the Tanzanian coast. From the Nguru Mountains a third Dendrobia species of the genus, D. plagata n. sp., is described.

Pollen transfer efficiency of <i>Apocynum cannabinum</i> (Apocynaceae): a comparative perspective

Pollen transfer efficiency (PTE), the percentage of removed pollen delivered to conspecific stigmas, has been implicated in the morphological evolution, population dynamics, and lineage diversification of flowering plants. Pollinia, the aggregated contents of pollen sacs, present in Apocynaceae subfamilies Asclepiadoideae (milkweeds), Secamonoideae, and Periplocoideae and orchids (Orchidaceae), are the pre-eminent example of a plant trait that elevates PTE (to ca. 25%). However comparison of species with pollinia to “average” flowers (PTE ca. 1%) may over-estimate the gains from pollinia. We hypothesize that elevated PTE evolved in Apocynaceae prior to pollinia. We measured PTE and pollen to ovule ratio, a possible correlate of PTE, in Apocynum cannabinum, a milkweed relative with pollen tetrads (instead of pollinia) and simple bands of style head adhesive (instead of complex pollinium-carrying translators), comparing them to reports of other species collated from the literature. PTE of A. cannabinum is 7.9%, in the 24th percentile of reports for 35 milkweed species, but more than twice the highest PTE reported for a species with monads (3.4%). The bands of style head adhesive are functionally equivalent to the translators of milkweeds. The pollen to ovule ratio of A. cannabinum, at 19.8, is in the 94th percentile of ratios reported for milkweeds (mean 9.6). Our results are consistent with the hypothesis that floral novelties of Apocynaceae that evolved prior to pollinia also promote aggregated pollen transport and elevated PTE.

Paratesticular desmoplastic small round cell tumour: an unusual tumour with an unusual fusion; cytogenetic and molecular genetic analysis combining RT-PCR and COBRA-FISH

Desmoplastic small round cell tumour is a rare malignant tumour with a male to female ratio of 4:1. It manifests mostly at serosal sites. Here we present a case of a 28-year-old male patient, who presented with a fast growing paratesticular mass. On biopsy nests and cords of small round cells, without a clear morphological lineage of differentiation were seen. Occasionally desmoplatic small round cell tumour shows different lines of differentiation. An unequivocal histological diagnosis might be difficult in such cases. Here we demonstrate by a combination of methods the characteristic immunohistochemical profile and - albeit unusual - molecular background and discuss the eventual link with Ewing sarcoma.Immunohistochemical studies showed a membranous staining of Keratine AE1/3 and a dot-like staining of Desmine, confirming its diagnosis. Using COBRA-FISH following a metaphase approach we demonstrated a balanced translocation, t(11;22)(p13;q12) and in RT-PCR formation of the EWSR1-WT1 fusion product, a specific translocation of desmoplastic round cell tumour. The fusion involves exon 9 of EWSR1 to exon 8 of WT1, an unusual fusion product, though earlier described in a case of a desmoplastic small round cell tumour of the hand. The EWSR1-WT1 chimera seems to function as an oncogenic transcription factor. Here the zinc finger domain of the WT1 acts with affinity with certain promoter domains influencing the expression of various downstream proteins such as: PDGFA, PAX2, insulin-like growth factor 1 receptor, epidermal growth factor receptor, IL2 receptor beta, BAIAP3, MLF1, TALLA-1, LRRC15 and ENT. We discuss their potential oncogenic roles and potential therapeutic consequences.

Control of cell fate decisions

It is well established that stem cell maintenance and differentiation are governed by unique local cues found in microenvironments. The future efficacy of stem cells in regenerative medicine relies upon maintaining their properties ex vivo prior to placing them into a foreign tissue environment. This editorial preface highlights key elements controlling cell fate decisions. The subject of cell fate, also referred to as the ultimate differentiated state to which a cell has become committed, is governed by the unique local microenvironment (or niche) (Fuchs et al. 2004; Watt and Hogan 2000). The successful use of stem cells in regenerative medicine relies upon the better identification of the specific cues in these microenvironments, so that when removed from their natural habitat, expanded ex vivo and then transplanted into foreign tissues, they will retain their ability to regenerate tissue. Whilst normally quiescent in the bone marrow, human mesenchymal stem cells (hMSC) cultured ex vivo spontaneously differentiate, apparently due to the abrupt change in their microenvironment. Until recently, a combination of appropriate soluble factors and extracellular matrix molecules was thought to hold the key to ex vivo manipulation. However, a recent report published in Cell (Engler et al. 2006) has proposed that naive mesenchymal stem cells specify lineage commitment to phenotypes based on tissue-level elasticity, such that soft (brain-like) matrices confer neurogenic phenotypes, whilst stiffer (muscle-like) matrices give rise to myogenic cells, and comparatively rigid (bone-like) matrices direct to osteogenic fates. Interestingly, early on during the lineagecommitment phase, reprogramming of these lineages is possible using soluble factors; however, after several weeks in culture, cell fate decisions are specified by matrix elasticity. Thus the physical nature of a stem cell’s microenvironment appears to be equally important for determining morphological change and lineage specification. As such, more attention is now being paid to the role of actin structures and focal adhesions, as matrix sensing requires a direct pathway of force transmission from the elastic matrix into the interior of the cell (Beningo et al. 2001; Tamada et al. 2004). Indeed complex membranespanning heparan sulfate proteoglycans (HSPGs) are also known to transfer spatial information pertaining to the cellular niche to bring about cell-based adhesion or migration, behaviors crucial to cell fate decisions. Moreover, ECM proteins (via the HS side-chains on HSPGs) and cytoskeletal proteins (via cytoplasmic domains of HSPGs) interact with cell-surface receptors (such as integrins) to induce cell spreading and the formation of focal adhesions (Couchman et al. 2001) (for review see Bishop et al. 2007). Ultimately, cell fate decisions thus depend on the integration of signals mediated through HSPG-binding and integrin-based adhesive mechanisms (Bishop et al. 2007). Many excellent reviews have been written on the role HSPGs play during embryological development and their importance in mammalian physiology (Bishop et al. 2007; Bulow and Hobert 2006; Hacker et al. 2005; Haltiwanger and Lowe 2004). HS side-chains bound to core protein are known to bind not only growth factors, cytokines and chemokines, but also morphogens (such as Wnt and Sonic S. M. Cool (&) Laboratory of Stem Cells and Tissue Repair, Institute of Molecular and Cell Biology, 61 Biopolis Drive, Singapore 138673 e-mail: scool@imcb.a-star.edu.sg

Mitochondrial DNA variation in honey bee (Apis mellifera L.) populations from Turkey

SummaryWe have studied mitochondrial (mt) DNA variation in 334 honey bee colonies from 7 different geographic regions of Turkey. We have evaluated Dra I restriction profiles of the CO-I CO-II intergenic region, Hinf-I and Taq-I restriction profiles of the CO-I gene and EcoR-I restriction profiles of the whole mtDNA. We obtained three different mtDNA patterns by EcoR-I digestion. The pattern typical for A. m. carnica/A. m. ligustica predominated throughout Turkey (327 colonies, 97.9%). We observed the pattern common in African subspecies only in Hatay province (6 colonies, 1.8%) and a previously unreported pattern in one colony from Balıkesir province (0.3%). Dra-I restriction analysis of the CO-I CO-II intergenic region yielded seven haplotypes. Haplotype 1 (TrDra-1) was the most common one found in Turkey, whereas haplotype 2 (TrDra-2) was widely distributed in Eastern Anatolia. Based on mitochondrial ND2 sequences taken from two samples collected in each region, bees from Hatay clustered with A. m. lamarckii and A. m. meda (morphological A and O lineages), while bees from central Anatolia clustered within the C morphological lineage group.

A chitinozoan morphological lineage and its importance in Lower Silurian stratigraphy

Margachitina margaritana is a distinctive, chain‐forming chitinozoan taxon of the uppermost Telychian Stage (Llandovery Series) to lower Homerian Stage (Wenlock Series). M. margaritana is shown to be the end member of a morphological lineage that developed from Calpichitina densa via the intermediate Margachitina banwyensis sp. nov. A local M. banwyensis Biozone, which correlates with the upper lapworthi graptolite Biozone, is proposed for the Banwy River section. The morphological lineage described provides a tool for the enhanced subdivision of the uppermost Llandovery Series, which may prove global in extent. This research suggests also that the base of the Wenlock Series may correlate with a level below the centrifugus graptolite Biozone and it also brings into question the systematic status of Calpichitina and Margachitina, although both genera are retained herein.

Application of morphological lineages in Australian palynostratigraphy

In terms of biostratigraphic subdivision dorected towards chronostratigraphic correlation, the lineage zone is of major significance. With the application of palynostratigraphy to time correlation however, morphological lineages are little used. This perhaps reflects the consideration of dispersed sporomorphs as a minor part of the total organism, studied in isolation from the total organism (often unknown), and thus with little known of their ecological associations. Additionally, trends of morphological change in dispersed spores are difficult to unravel and define. This is the result of a combination of factors including the artificial nature of morphological classifications adopted, that one morphotype can be a product of several, very different distantly related parent plants and that plant speciation is often a product of hybridization and polyploidy. Several types of morphological series have been defined from Australian Palaeozoic and Mesozoic microfloral succession. Some of these have proved to be valuable in assisting time correlation of the stratigraphic sequence while others are inherently unreliable for such correlation studies. These differences can be accounted for in terms of biological controls on small scale morphological variations. Consequently it is essential that the biological significance of a morphological lineage be assessed before accepting its value in chronostratigraphic correlation.